Field of the Invention
[0001] The present invention relates to a composition comprising a biologically pure isolate
of the micro-organism
Duddingtonia flagrans (D. flagrans) having all of the identifying characteristics of the strain deposited under Accession
No. V16/019156 at National Measurement Institute, 1/153 Bertie Street, Port Melbourne,
Victoria 3207, Australia referred to herein as "IAH 1297", the production thereof
by fermentation on a solid substrate that is a moistened grain, legume or oilseed,
and the use thereof in a method of controlling the spread of a parasitic nematode
in a grazing animal.
Background of the Invention
[0002] Parasitic nematodes (intestinal worms) remain a major threat to the health and welfare
of grazing animals (with a digestive system that is highly adapted to a grass diet)
all over the world. In particular, grazing animals are exposed to parasites at very
high frequency. Grazing animals become re-infected after treatment because they pick
up nematodes by grazing on pasture which is infected with worm larvae. These larvae
originate from the manure piles containing large numbers of nematode eggs deposited
by wormy animals.
[0003] More particularly, as shown in Figure 1, the basic lifecycle of gastrointestinal
nematodes (GIN) involve adult worms in the predilection site in the host's gastrointestinal
tract producing large numbers of eggs that are passed from the host i.e., shed in
the faeces. In the faecal pats or on the pasture the eggs typically undergo further
development through two feeding stages (this development period varies between the
different parasite species and is dependent on environmental conditions). The first
stage larvae (L1) molt into second stage larvae (L2) and then into non-feeding infective
third stage larvae (L3). The L1 and L2 larvae feed on organic matter in the faeces
whereas the L3 larvae are unable to feed due to the retention of the cuticle from
the L2 stage. The cuticle serves as a protective sheath from extreme environmental
conditions and can extend the survival of the larvae until optimal conditions are
present for further development (
Pugh, D.G. et al., Comp Cont Educ Pract Vet 20 (1998): S112). The infective L3 subsequently migrate from the faeces onto surrounding pasture,
where they are ingested by other grazing animals, thereby propagating the parasitic
infection. Once inside the host, the L3 ex-sheath in response to changes in CO
2 concentration, temperature and pH before they reach their site of infection. They
undergo two further molts (L4 and L5) and complete their development to adults at
their preferred site in 15 - 21 days for most common species (
Vlassoff, A. et al., (2001) New Zealand Veterinary Journal 49: p213-221).
[0004] During migration and establishment of the larvae/adults direct damage may be caused
to the digestive tract. Damage may also be caused by inflammation at the site of infection
as the host responds to the invading parasite. Several worldwide reports have suggested
that such parasitic diseases inflict severe economic losses on the livestock industry
and adversely affect the health of animals. Diarrhoea, anaemia, weight loss, decreased
reproduction, decreased production (e.g. wool quality, milk production, etc.), and
increased morbidity and mortality are just some of the devastating losses that gastrointestinal
nematodes (GIN) can create. In the domestic small ruminant industry alone worldwide,
there is an estimated production loss extending into the millions of dollars each
year. Exact values are difficult to obtain due to the many factors that affect loss
which include management, nutrition, environmental factors, stress, genetics and concurrent
disease (
Vlassoff, A. et al., (2001) New Zealand Veterinary Journal 49: p213-221). The estimated losses in sheep and cattle in Australia alone is $A1 billion and
worldwide it extends to tens of billions of dollars (
Roeber et al., (2013) Parasite & Vectors 6: p153). In another study published by Meat & Livestock Australia Limited (
Lane et al., (2015) Report B.AHE.0010 ISBN 9781741918946) estimates of the total losses per annum in Australia due to internal parasites were:
Cattle $A93.6 million ($US70m/$EU66m) with production losses ranging from $0.44 -
$3.59 per animal
Sheep $A436 million ($US327m/$EU305m) with production losses ranging from $1.29 -
$28.29 per animal
Goats $A2.54 million ($US1.9m/$EU1.8m) with production losses ranging from $0 - $5.34
per animal.
[0005] Exotic or nondomestic ruminant species such as giraffe, antelope, deer, oryx, sable,
blackbuck, bongo, okapi, and wildebeest are a few of the many species of artiodactylids
that also exhibit GIN infections. GIN infections are not as severe and numerous in
wild artiodactylids in their natural habitats as they are in captive artiodactylids
in zoological facilities. Reasons for increased numbers of GIN and severity of infection
in captive artiodactylids are due to stress, the lack of browse in enclosures, increased
stocking rates, irrigation and the inability to close exhibits. Stressful conditions
caused by captivity can decrease the function of the immune system and increase the
body's exposure to parasites and diseases (
Fagiolini, M. (2010) et al., Journal of Zoo and Wildlife Medicine, 41(4): p662-670). In zoological facilities, guests must be able to view animals in their enclosures.
For that reason, there is a decreased availability of browse, which allows animals
that are natural browsers in the wild, such as giraffe, to graze instead. However,
it is difficult to predict the extent of infection in such forced "grazers" compared
to domestic grazing animals, as it would depend upon the extent of actual grazing
compared to browsing provided in such conditions.
[0006] Globally, among the most important gastrointestinal nematode (GIN) parasites of livestock
include those which belong to the genera
Haemonchus, Ostertagia, Teladorsagia, Trichostrongylus, Ascaris, Nematodirus, Strongyloides,
Trichuris, Chabertia, Oesophagostomum, Cooperia and
Bunostomum (
Yong, W. K. 1992. In: Yong, W. K (Ed.) Animal Parasite Control Utilizing Biotechnology.
pp. 115-134. CRC Press, Florida, USA). For ruminants, the major species are
Haemonchus spp.,
Teladorsagia (
Ostertagia) spp.,
Cooperia spp., and
Trichostrongylus spp. while for horses the major species are cyathostomes,
Strongylus spp.,
Strongyloides westeri, Parascarus equorum, Trichostrongylus axei and
Dictyocaulis arnfeldi. The adult nematode will preferentially inhabit a particular segment of the host gastrointestinal
tract (see Table 1).
Table 1 The important nematodes of grazing animals in Australia, their common names
and the anatomical site in which they are located
| Anatomical site |
Scientific name |
Common name |
| Abomasum (ruminants) |
Haemonchus contortus |
barbers pole worm |
| H. placei |
barbers pole worm |
| Teladorsagia (Ostertagia) spp. Trichostrongylus axei |
small brown stomach worm stomach hair worm |
| Small intestine |
Cooperia spp. |
intestinal worm |
| Nematodirus spp. |
thin necked intestinal worm |
| Trichostrongylus spp. |
black scour worm |
| Bunostomum trigonocephalum |
hook worm |
| Strongyloides papillosis |
thread worm |
| Strongyloides westeri |
thread worm |
| Parascarus equorum |
round worms |
| Large intestine |
Chabertia ovina |
large mouthed bowel worm |
| Oesophagostomum columbianum |
nodule worm |
| Oe. Vendosum |
- |
| Trichuris ovis |
whipworm |
| Cyathostomins |
small strongyles |
| Strongylus spp. |
large strongyles |
| Oxyuris equi |
pin worms |
[0007] Of these parasitic species,
H. contortus, a parasite of the abomasum of ruminants, is very significant with respect to global
economic impact and clinical disease because it is a blood feeding parasite that can
cause severe anaemia in animals and is prevalent around the world where there is a
mean monthly temperature of 18°C and rainfall of 50mm. This particular parasite, for
example, is endemic to the South-eastern United States, Europe and Australasia as
well as other areas that have climates of high temperature and humidity. https://www.researchgate.net/publication/6904034_Haemonchus_contortus_parasite_proble
m_No_1_from_tropics_-_Polar_Circle_Problems_and_prospects_for_control_based_on_epidemiology.
[0008] Presently, the conventional approach to management of intestinal parasites in grazing
animals is chemotherapy i.e. administration of chemical agents intended to kill the
parasitic nematodes which cause disease. These chemicals are known as anthelmintics.
This approach has been used with great success around the world but has led to over-reliance
on these drugs which, in turn, has led to the evolution of drug-resistance which is
undermining the treatment paradigm.
[0009] The 1960s and 1970s, when the regime of chemotherapy was established, was a period
in which the general availability of drugs and the emergence of new drugs flourished.
However, the pipeline has dried-up and the outlook for further innovations in drug
therapy is bleak (
Ihler, C. F., (2010) Acta Veterinaria Scandinavica, 52 (Suppl 1):S24). Generally, resistance to a new chemical becomes evident after just 5-10 years of
use, as shown in the in Figure 2. There have been recent cases of resistance developing
at a faster pace. For example, in 2013 it was reported that monepantel (a new anthelmintic
drug) had become completely ineffective against
Teladorsagia circumcincta and
Trichostrongylus colubriformis after just two years use on a goat farm in New Zealand (
Scott, I. et al, (2013) Veterinary Parasitology 198 (1-2) 166-171. Due to varying compliance of orally administered medications, estimated body weights,
as well as unknown pharmacokinetic data, has led to the use of sub-therapeutic doses.
This, along with overuse and poor pasture management has contributed to the current
anthelmintic resistance problem worldwide.
[0010] Administration of the chemicals also gives rise to chemical residues in the meat
and milk products obtained from the recipient animals. It also causes unintended contamination
of the environment through spillages and excretion in urine and faeces. Although resistance
in parasites is increasing, commercial farming continues to rely on the use of anthelmintics.
[0011] In view of the above problems with anthelmintic use, there remains an urgent need
for other control methods in commercial settings e.g., on farms and/or zoos. Biological
control methods provide a means for chemical-free control of parasitic nematodes by
utilising the capabilities of microbial agents which have biological properties adapted
for this purpose. Nematophagous fungi have emerged in recent years as promising biological
control agents of parasitic nematodes of livestock (
Larsen et al., (1997) Veterinary Parasitology 72: p479-85;
Waller and Faedo, (1996) International Journal for Parasitology 26: p915-925). Many studies have shown
Duddingtonia flagrans (D. flagrans) to have potential as a control agent. D.
flagrans is a nematophagous fungus that is adapted to trapping and digesting the infective
larvae of nematode (worm) species, which are parasitic to grazing animals. The spores
of the fungus are particularly thick-walled and so when fed to grazing animals, can
pass through their digestive tracts intact and are deposited in their manure. In particular,
D. flagrans produces large chlamydospores (approx. 20 µm), which survive gut passage. As discussed
above, the animals also shed the eggs of their parasites into their manure. In the
manure pats, the fungus proliferates, traps and consumes the infective larvae that
hatch from the worm eggs, as illustrated in Figure 3. This interrupts the worms' life
cycle and thus,
D. flagrans was considered to be potentially useful as a biological control for parasitic worms
of grazing animals.
[0012] Despite the vast research that has been conducted on the use of
D. flagrans in the biological control of parasitic worms in the last 20 years (
Buzatti et al., (2015) Experimental Parasitology 159: p1-4;
Khan et al., (2015) Animal Nutrition and Feed Technology 15(3): p447-456;
Waller et al. (2001) Veterinary Parasitology 102(4): p321-330;
Burke et al. (2005) Veterinary Parasitology 134(1-2): p141-146;
US 5643568 A;
WO 2014/125154 A1;
CN 105343879 A;
Anonymous: "Biological Control of Nematode Parasites of Small Ruminants in Asia -
Final Proceedings of FAO Technical Co-operations Project in Malaysia TCP/MAL/0065
(T) 2002", Food and Agriculture Organization of the United Nations, (2002-09-16),
pages 1-11.), the outcomes in this area have proved disappointing, so much so that no commercial
products have emerged. In particular, a plethora of feeding studies using a variety
of dosages of
D. flagrans highlight numerous problems associated with the development of a commercial product
comprising
D. flagrans suitable for use in grazing animals. A study conducted in 2005 highlights the inconsistencies
in results obtained from field trials, describing a high variability in efficacy obtained
with voluntary ingestion, which may accentuate differences in efficacy between doses
and which is a major pitfall with environmental use despite efficacy observed in only
some groups (
Paraud etal., Vet. Res. (2005) 36: p157-166).
Waller et al. Acta. Vet. Scand. (2006) 47: p23-32) describe trials conducted on three commercial sheep farms in Sweden to evaluate
the administration of
D. flagrans under a range of commercial farming operations and whether or not commercial application
of a biological product comprising
D. flagrans would be feasible. These trials showed that there was no significant benefit in performance
of lambs in the fungal treatment for all three farms used in this study.
[0013] It has further been reported by
Terrill et al. (Veterinary Parasitology 186 (2012): p28-37) that work with nematode trapping fungi was discontinued by the Southern Consortium
for Small Ruminant Parasite (SCSRPC) after an encouraging start because of a lack
of commercial source of the spores. Moreover, whether the use of
D. flagrans is feasible under grazing conditions with consistent reproducible efficacy, along
with long-term use to reduce the gastrointestinal nematode larval numbers on pasture
(thereby reducing infection rates and improving animal performance), remains to be
seen. Indeed a further review published by
Kumar et al., (J. Parasit. Dis. (2013) 37(2): p151-157) indicates there is an urgent need to design a sustainable parasite control strategy.
Moreover, whilst recent experimental studies describe
D. flagrans as being the "most promising" biological control agent for nematode parasites in
grazing animals, researchers have begun to study combinations of
D. flagrans with other nematophagous fungi (e.g., see
Da Silva et al. Biomed Res. Intl. (2015) Article ID 474879). However, such combinations have yet to be tested in commercial farm settings and/or
zoos and are likely to present even greater problems of reproducibility and efficacy
under the varying field conditions compared with the use of one biological agent alone.
[0014] As discussed above, the use
D. flagrans to control infective larvae on the pasture showing consistent reproducible efficacy
has met with much difficulty due to high variance between results obtained under experimental
conditions, those obtained in field trials and under commercial farm settings, as
well as the difficulties associated with fermentation and scale up to produce commercial
quantities of a usable product i.e., the spores. Accordingly, despite the existence
of numerous studies describing the potential to use of
D. flagrans as a biological control agent none of the strains used have successfully led to a
commercially available product. No specific information about strain IAH 1297 are
available (e.g., how to derive the strain or what are the characterizing properties)
(
Anonymous: "BioWorma (Application Summary for Application No 106347)", Australian
Pesticides & Veterinary Medicines Authority, (2016-07-20), pages 1-40,
Anonymous: "Livamol with BioWorma (Application Summary for Application No 106348)"
Australian Pesticides & Veterinary Medicines Authority, 20 July 2016 (2016-07-20),
pages 1-12,
Anonymous: "BioWorma and Livamol with BioWorma", EPA NZ Decision APP202832, 3 August
2016 (2016-08-03), pages 1-19). There remains a need for a composition comprising
D. flagrans that provides reproducible control of the spread and infectivity of livestock and
pasture by parasitic nematodes and that is suitable for commercialisation and/or applicable
for use in a sustainable commercial parasite control strategy.
[0015] Any discussion of the prior art throughout the specification should in no way be
considered as an admission that such prior art is widely known or forms part of common
general knowledge in the field.
[0016] It is an objective of the present invention to overcome or ameliorate at least one
of the disadvantages of the prior art treatments, or to provide a useful alternative.
Summary of the Invention
[0017] Despite the lack of success in the art with attempts to produce a biological control
product comprising
D. flagrans, in work leading up to the present invention, the inventors sought to identify an
isolate of a
D. flagrans strain for use in a biological control composition suitable for commercial application.
The inventors have surprisingly found an isolated
D. flagrans strain, referred to in the present application as "IAH 1297", that has characteristics
suitable for commercial application. The
D. flagrans strain of the present application provides numerous advantages over known strains
as discussed below.
[0018] The present invention is directed to the embodiments as defined in the claims. The
present invention provides a composition comprising a biologically pure isolate of
the microorganism
Duddingtonia flagrans (D. flagrans) having all of the identifying characteristics of the strain deposited under Accession
No. V16/019156 at National Measurement Institute, 1/153 Bertie Street, Port Melbourne,
Victoria 3207, Australia on 2 August 2016 (referred to herein as "strain IAH 1297").
The present invention further relates to a composition for use in a method of controlling
the spread of a parasitic nematode in a grazing animal comprising a biologically pure
isolate of the micro-organism
Duddingtonia flagrans (D. flagrans) having all of the identifying characteristics of the strain deposited under Accession
No. V16/019156 at National Measurement Institute, 1/153 Bertie Street, Port Melbourne,
Victoria 3207, Australia referred to herein as "IAH 1297".
In addition, the present invention relates to a method of producing a biologically
pure isolate of the micro-organism
Duddingtonia flagrans (D. flagrans) by fermentation the method comprising fermenting an isolate of
D. flagrans having all of the identifying characteristics of the strain deposited under Accession
No. V16/019156 at National Measurement Institute, 1/153 Bertie Street, Port Melbourne,
Victoria 3207, Australia referred to herein as "IAH 1297" on a solid substrate, wherein
the solid substrate is a moistened grain, legume or oilseed.
[0019] It will be apparent to a person skilled in the art that the term "biologically pure
isolate" as used herein means that the isolate is separated from an environment of
one or more constituents with which it may be associated if found in nature or otherwise.
The terms "biologically pure" or "isolate" as used herein does not indicate the extent
to which the microorganism has been purified. In one embodiment, strain IAH 1297 is
the only D.
flagrans strain present in the isolate and in another embodiment, the strain IAH 1297 is the
only microorganism present in the isolate.
[0020] It will be clear to the skilled addressee that the present invention relates to a
composition comprising the strain IAH 1297 in any of its life forms (see discussion
above regarding the various life-cycle stages of
D. flagrans). Preferably, strain IAH 1297 is in the form of a spore and more preferably it is
in the form of a chlamydospore.
[0021] The composition according to the invention may comprise any functional part of the
D. flagrans microorganism strain IAH 1297, as described herein, including a spore. Preferably,
the composition comprises a spore of said strain IAH 1297 and, more preferably, the
spore is in the form of a chlamydospore.
[0022] The present invention provides a composition comprising an isolated
D. flagrans strain IAH 1297 and/or a spore of said isolated
D. flagrans strain (preferably a chlamydospore of said isolated
D. flagrans strain), wherein said composition interrupts the life-cycle of a parasitic nematode
in a grazing animal, controls the spread of the nematode in a grazing animal and is
suitable for commercial application.
[0023] The compositions of the present invention are useful as biological control compositions
to interrupt the life-cycle of a parasitic nematode that infects a grazing animal.
The biological control compositions control the spread of the nematode and are suitable
for commercial application.
[0024] Without being bound to any particular theory, it is thought that when a composition
of the present invention is fed to a grazing animal, the thick-walled spore of
D. flagrans (preferably the chlamydospore) remains inert, resists digestion and passes through
the digestive tract and is eventually shed into manure. The
D. flagrans spores of the composition germinate in the manure and form trapping organs trapping
the larvae of the parasitic nematode and killing them thereby interrupting the life-cycle
of the parasitic nematode in a grazing animal. This controls the spread of the nematode
from the manure onto the pasture by reducing the number of larvae emerging from manure.
By controlling the emergence of larvae from the manure, the composition of the invention
controls the spread of parasitic nematodes of grazing animals thereby reducing infectivity
of the parasitic nematode. The larvae include e.g., L1, L2 and/or L3 larvae. Preferably,
the composition reduces L3 larvae emerging from manure and/or on the pasture. Accordingly,
it will be apparent to the skilled artisan that the term "controls the spread of the
nematode" includes controlling the spread of parasitic nematodes of grazing animals.
It will also be understood that controlling the spread of a parasite in a grazing
animal means reducing the infectivity by the parasitic nematode whereby the population
of the pathogen is below a threshold level where clinical problems and/or economic
losses of livestock (the grazing animals) are reduced.
[0025] For example, the composition according to the invention interrupts the life-cycle
of a parasitic nematode in a grazing animal and controls the spread of the nematode
when the reduction of larvae in manure and/or onto pasture is reduced in the range
of 30% to 100%, or 35% to 100%, or 40% to 100%, or 45% to 100%, or 50% to 100%, or
55% to 100%, or 60% to 100%, or 65% to 100%, or 70% to 100%, or 75% to 100%, or 80%
to 100%, or 85% to 100%, or 90% to 100%, or 95% to 100%, or about 100%. Preferably,
the composition according to the invention interrupts the life-cycle of a parasitic
nematode in a grazing animal and controls the spread of the nematode when the reduction
of larvae in manure and/or onto pasture is reduced in the range of 50% to 100%, more
preferably in the range of 70 to 100%, even more preferably in the range of 80 to
100%. In one example, the composition according to the invention interrupts the life-cycle
of a parasitic nematode in a grazing animal and controls the spread of the nematode
when the reduction of larvae in manure and/or onto pasture is reduced in the range
of about 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%, or 95%,
or 100%.
[0026] The composition of the invention is also one that is suitable for commercial application
i.e., application to animals held on a farm including large commercial farms, and/or
animals held in an enclosure and/or zoo setting. Accordingly, it will be understood
that the composition of the invention is suitable for commercial application and may
be fed directly to the grazing animal and/or by mixing into feed and/or provided with
a feed supplement, or the composition of the invention may be formulated further and
provided as a feed, feed supplement, bolus or veterinary medicinal composition. The
feed or feed supplement may be in any form suitable for feeding grazing animals including,
but not limited to; a loose mix, a liquid feed/supplement, pellet or lick block.
[0027] It is preferable that the composition of the invention is a commercial product having
at least one or more of the following characteristics:
Characteristic 1: Able to be produced in sufficiently large quantities to allow deployment into commercial
grazing systems
Characteristic 2: Efficacy after large-scale production and performance on-farm and/or animals held
in an enclosure and/or zoo setting in accordance with the label claims.
Characteristic 3: Safety for recipient animals and their human handlers.
Characteristic 4: Stability and shelf life. Preferably, the biological control product has a shelf
life of at least 12 months, or at least 18 months or longer at room temperature (up
to 30°C).
Characteristic 5: Suitable physical form. The physical form of the product should be suited to its
intended end use i.e. free flowing and easy to blend with animal feed.
Characteristic 6: Palatability - Since the products are intended for routine oral administration in-feed,
a taste and texture which is acceptable to the recipient animals.
Characteristic 7: Packaging / pack sizes - it is desirable to have robust packaging, easy to handle
on farm and pack sizes appropriate for the end-use.
Characteristic 8: Purity - the microbial agents should be produced in a form sufficiently pure for
safe administration to animals.
Characteristic 9: Suitability for use in either individual feeding or group feeding situations. Sometimes,
grazing animals will be fed on an individual basis. More generally, grazing animals
are fed in a group feeding situation such as a shared trough. This can lead to situations
where feed intake of timid animals is inhibited and more aggressive animals can consume
more than their share.
[0028] Despite significant research with
D. flagrans, until the present invention, a commercial product has not been provided that has
at least the characteristics 1 and 2 above. In one embodiment, the composition comprises
at least two, or at least three, or at least four, or at least five, or at least six,
or at least seven, or at least eight or at least nine of the above characteristics
1 to 9.
[0029] Preferably, the composition comprises each of the above characteristics 1, 2, 3,
6 and 7. Even more preferably, the composition comprises each of the above characteristics
1 to 9.
[0030] Efficacy after large scale production and performance on farm and/or animals held
in an enclosure and/or zoo in accordance with the label claims in-part relates to
the amount of viable spores of
D.
flagrans in the composition. As such, the composition according to the invention may comprise
a viable count of
D.
flagrans spores of at least about 1 × 10
2 viable spores per gram of composition.
[0031] In one embodiment, the composition according to the invention may comprise a viable
count of
D. flagrans spores in the range of 1 × 10
2 to 1 × 10
10 viable spores per gram of composition. For example, the composition according to
the invention may comprise a viable count of
D.
flagrans spores of:
1 × 102 to 1 × 103 viable spores per gram of composition, or
1 × 103 to 1 × 104 viable spores per gram of composition, or
1 × 104 to 1 × 105 viable spores per gram of composition, or
1 × 105 to 1 × 106 viable spores per gram of composition, or
1 × 106 to 1 × 107 viable spores per gram of composition, or
1 × 107 to 1 × 108 viable spores per gram of composition, or
1 × 108 to 1 × 109 viable spores per gram of composition, or
1 × 109 to 1 × 1010 viable spores per gram of composition.
[0032] Preferably, the composition according to the invention may comprise a viable count
of
D. flagrans spores in the range of 1 × 10
2 to 1 × 10
8 viable spores per gram of composition.
[0033] In another embodiment, the composition according to the invention may comprise a
viable count of
D. flagrans spores of
- (a)
1 × 102 to 5 × 106 viable spores per gram of composition, or
1 × 102 to 1 × 106 viable spores per gram of composition, or
1 × 103 to 1 × 106 viable spores per gram of composition, or
1 × 103 to 5 × 105 viable spores per gram of composition, or
1 × 104 to 5 × 105 viable spores per gram of composition, or
1 × 104 to 1 × 105 viable spores per gram of composition, or
- (b)
1 × 104 to 1 × 108 viable spores per gram of composition, or
1 × 104 to 5 × 107 viable spores per gram of composition, or
1 × 104 to 1 × 107 viable spores per gram of composition, or
1 × 105 to 5 × 106 viable spores per gram of composition, or
1 × 105 to 1 × 106 viable spores per gram of composition, or
- (c)
1 × 105 to 1 × 108 viable spores per gram of composition, or
1 × 105 to 1 × 107 viable spores per gram of composition, or
1 × 106 to 1 × 107 viable spores per gram of composition.
[0034] In another example, the composition according to the invention may comprise a viable
count of
D. flagrans spores of
- (a) about 1 × 102, or about 1.5 × 102, or about 2 × 102, or about 2.5 × 102, or about 3 × 102, or about 3.5 × 102, or about 4 × 102, or about 4.5 × 102, or about 5 × 102, or about 5.5 × 102, or about 6 × 102, or about 6.5 × 102, or about 7 × 102, or about 7.5 × 102, or about 8 × 102, or about 8.5 × 102, or about 9 × 102, or about 9.5 × 102; or;
- (b) about 1 × 103, or about 1.5 × 103, or about 2 × 103, or about 2.5 × 103, or about 3 × 103, or about 3.5 × 103, or about 4 × 103, or about 4.5 × 103, or about 5 × 103, or about 5.5 × 103, or about 6 × 103, or about 6.5 × 103, or about 7 × 103, or about 7.5 × 103, or about 8 × 103, or about 8.5 × 103, or about 9 × 103, or about 9.5 × 103; or;
- (c) about 1 × 104, or about 1.5 × 104, or about 2 × 104, or about 2.5 × 104, or about 3 × 104, or about 3.5 × 104, or about 4 × 104, or about 4.5 × 104, or about 5 × 104, or about 5.5 × 104, or about 6 × 104, or about 6.5 × 104, or about 7 × 104, or about 7.5 × 104, or about 8 × 104, or about 8.5 × 104, or about 9 × 104, or about 9.5 × 104; or
- (d) about 1 × 105, or about 1.5 × 105, or about 2 × 105, or about 2.5 × 105, or about 3 × 105, or about 3.5 × 105, or about 4 × 105, or about 4.5 × 105, or about 5 × 105, or about 5.5 × 105, or about 6 × 105, or about 6.5 × 105, or about 7 × 105, or about 7.5 × 105, or about 8 × 105, or about 8.5 × 105, or about 9 × 105, or about 9.5 × 105; or
- (e) about 1 × 106, or about 1.5 × 106, or about 2 × 106, or about 2.5 × 106, or about 3 × 106, or about 3.5 × 106, or about 4 × 106, or about 4.5 × 106, or about 5 × 106, or about 5.5 × 106, or about 6 × 106, or about 6.5 × 106, or about 7 × 106, or about 7.5 × 106, or about 8 × 106, or about 8.5 × 106, or about 9 × 106, or about 9.5 × 106, or
- (f) about 1 × 107, or about 1.5 × 107, or about 2 × 107, or about 2.5 × 107, or about 3 × 107, or about 3.5 × 107, or about 4 × 107, or about 4.5 × 107, or about 5 × 107, or about 5.5 × 107, or about 6 × 107, or about 6.5 × 107, or about 7 × 107, or about 7.5 × 107, or about 8 × 107, or about 8.5 × 107, or about 9 × 107, or about 9.5 × 107, or
- (g) about 1 × 108, or about 1.5 × 108, or about 2 × 108, or about 2.5 × 108, or about 3 × 108, or about 3.5 × 108, or about 4 × 108, or about 4.5 × 108, or about 5 × 108, or about 5.5 × 108, or about 6 × 108, or about 6.5 × 108, or about 7 × 108, or about 7.5 × 108, or about 8 × 108, or about 8.5 × 108, or about 9 × 108, or about 9.5 × 108, or
- (h) about 1 × 109, or about 1.5 × 109, or about 2 × 109, or about 2.5 × 109, or about 3 × 109, or about 3.5 × 109, or about 4 × 109, or about 4.5 × 109, or about 5 × 109, or about 5.5 × 109, or about 6 × 109, or about 6.5 × 109, or about 7 × 109, or about 7.5 × 109, or about 8 × 109, or about 8.5 × 109, or about 9 × 109, or about 9.5 × 109, or about 1 × 1010
viable spores per gram of composition.
[0035] More preferably, the composition according to the invention may comprise a viable
count of
D. flagrans spores of
- (a) about 1 × 104, about 3 × 104, or about 1 × 105 viable spores per gram of composition; or
- (b) about 1 × 105, about 5 × 105 or about 1 × 106 viable spores per gram of composition; or
- (c) about 1 × 106, about 3 × 106 or about 1 × 107 viable spores per gram of composition; or
- (d) about 3 × 106, about 1 × 107 or about 1 × 108 viable spores per gram of composition.
[0036] The composition is prepared according to any method suitable to produce the
D. flagrans strain IAH 1297 and/or spore of said isolated
D. flagrans strain. In addition, the present invention provides a method of producing a biologically
pure isolate of the micro-organism
Duddingtonia flagrans (D. flagrans) by fermentation the method comprising fermenting an isolate of
D. flagrans having all of the identifying characteristics of the strain deposited under Accession
No. V16/019156 at National Measurement Institute, 1/153 Bertie Street, Port Melbourne,
Victoria 3207, Australia referred to herein as "IAH 1297" on a solid substrate, wherein
the solid substrate is a moistened grain, legume or oilseed. Preferably the spore
is a chlamydospore. Preferably, the method is a fermentation method that provides
the
D. flagrans viable spores per gram of composition according to the invention. In one example,
the
D. flagrans strain and/or spore of said isolated
D. flagrans strain is produced by a solid substrate fermentation method, wherein the solid substrate
is a moistened wholegrain, legume or oilseed. The wholegrain used may be any suitable
wholegrain useful for such a purpose including, but not limited to, barley, rye, millet,
rice, wheat, sorghum, triticale, oat, buckwheat, amaranth, corn, quinoa, teff or lupin.
The solid substrate may also include moistened legume including, but not limited to,
chickpea, faba/broadbean, field pea, lentil,lupin or mungbean; or the substrate may
be oilseed including, but not limited to soybean, canola, safflower, sunflower and
sesame seed. For example, the method may be the method described in Examples 2 and
3.
[0037] It will also be understood that the composition may be in any form such that the
composition is suitable for commercial application as described herein. For example,
the composition may be in the form of a spore concentrate including mycelium of the
D. flagrans and/or spores of the
D. flagrans, wherein preferably the spores are chlamydospores. For example, when solid substrate
fermentation is used, the wholegrain may be dried and ground to produce the composition
of the invention, wherein the wholegrain includes mycelium of the
D. flagrans and/or spores of the
D. flagrans, wherein preferably the spores are chlamydospores.
[0038] It is also contemplated that the composition according to the invention, including
the spore concentrate described herein, may be mixed with or prepared as a feed, feed
supplement, bolus or veterinary medicinal composition. The feed or feed supplement
may be in any form suitable for feeding grazing animals including, but not limited
to; a loose mix, a liquid feed/supplement, pellet or lick block.
[0039] In another aspect, the present invention provides use of the composition according
to the invention in the manufacture of a feed in any form, feed supplement, bolus
or veterinary medicinal composition for controlling the spread of a parasitic nematode
in a grazing animal.
[0040] In another aspect, the present invention provides use of the composition according
to the invention in controlling the spread of a parasitic nematode in a grazing animal.
[0041] The composition according to the invention may also be formulated for administration
to easily provide an amount of viable
D. flagrans spores per Kg bodyweight of the grazing animal per day. In one embodiment the composition
may be formulated for administration to provide at least about 1 × 10
3 viable
D. flagrans spores per Kg bodyweight of the grazing animal per day. In another embodiment, the
composition may be formulated for administration to provide
1 × 103 to 5 × 108 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 108 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 108 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 107 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 107 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 107 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 106 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 106 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 106 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 105 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 105 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 105 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 9 × 103 viable D. flagrans spores per Kg bodyweight of the grazing animal per day.
Preferably the composition may be formulated for administration to provide 1 × 10
4 to 1 × 10
5 viable
D. flagrans spores per Kg bodyweight of the grazing animal per day.
[0042] For example, the composition may be formulated for administration to provide:
about 1 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 1.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 2 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 2.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 3 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 3.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 4 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 4.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 5.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 6 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 6.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 7 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 7.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 8 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day,
or
about 8.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 9 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day.
or
about 1 × 105 viable D. flagrans spores per Kg bodyweight of the grazing animal per day.
[0043] More preferably, the composition may be formulated for administration to provide
about 1 × 10
4, about 3 × 10
4 or about 1 × 10
5 viable
D. flagrans spores per Kg bodyweight of the grazing animal per day. Most preferably, the composition
or biological control product may be formulated for administration to provide an amount
of viable
D. flagrans spores of about 3 × 10
4 viable spores per Kg bodyweight of the grazing animal per day. It will also be understood
that the composition of the invention may be formulated for administration to provide
a standard amount, as desired, of composition wherein the above amounts of viable
spores are provided per day.
[0044] It is also contemplated that "additional components" may be added to the composition
of the invention which also control the spread of a parasite in a grazing animal e.g.,
components that provide a "double-strike" effect. Such additional components include,
but are not limited to, anthelmintics (such as abamectin, ivermectin, pyrantel pamoate,
pelletierine sulphate) which are effective against nematodes; or such as benzimidazoles
(BZ), which are also ovicidal (with activity against eggs being passed by intestinal
nematodes and tapeworms), macrocyclic lactones (ML), imidazothiazoles and tetrahydropyrimidines
(LV), salicylanilides, nitazoxanide, praziquantel, octadesipeptides (eg. emodepside),
derquantel (spiroindole) and aminoacetonitrile derivatives (AAD) which are effective
against other worms, other nematophagous fungi (such as
Purpureocillium lilacinum, Stopharia rugosoannulata or
Coprinus comatus), tannins, minerals, diatomaceous earth, herbs, agricultural by-products, vaccines
or copper oxide wire particles (COWP) or combinations thereof. The invention provides
a composition that may further comprise one or more of the components from the following
group: one or more anthelmintics, one or more other nematophagous fungi, copper oxide
wire particles (COWP), a tannin, a mineral, diatomaceous earth, a herb, an agricultural
by-product, one or more bacteria or a vaccine. Suitable dosages of these additional
components will be clear to the skilled addressee based on the available scientific
and commercial (product-specific) literature as well as the skilled addressee's own
common general knowledge. In one embodiment, the composition further comprises COWP.
For example, the COWP may be present in the composition of the invention in an amount
suitable for administration to an animal at a dose of about 10g per 100 Kg bodyweight
of the animal to be treated.
[0045] In another aspect, the present invention provides a composition for use in a method
of controlling the spread of a parasitic nematode in a grazing animal comprising administering
the composition of the invention in an amount and for a time sufficient to reduce
the parasitic nematode (worm) burden on pasture by at least about 30%. For example,
the composition may be administered in an amount and for a time sufficient to reduce
the parasitic nematode (worm) burden on pasture in the range of 30% to 100%, or 35%
to 100%, 40% to 100%, or 45% to 100%, or 50% to 100%, or 55% to 100%, or 60% to 100%,
65% to 100%, or 70% to 100%, or 75% to 100%, or 80% to 100%, or 85% to 100%, or 90%
to 100%, 95% to 100%, or about 100%. Preferably, the composition may be administered
in an amount and for a time sufficient to reduce the parasitic nematode (worm) burden
on pasture in the range of 50% to 100%, more preferably in the range of 60 to 100%.
[0046] It will be apparent to the skilled artisan that the time sufficient to reduce parasitic
nematode (worm) burden on pasture may vary according to the type of grazing animal,
the animal's health condition and/or weight, and/or conditions of pasture, time of
year, temperature and/or climate and will be determined by the user or their technical
advisors.
[0047] Due to the development of resistance and multi-resistance to chemical anthelmintics,
scientists worldwide recommend using faecal egg counts (FEC) to indicate which grazing
animals need worming and when. It is also recommended that a faecal egg-count reduction
test (FECRT) be performed from time to time to check whether the anthelmintics being
used are effective and/or for identifying worm species by using faecal larval cultures
(FLC). http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0037327.
[0048] For example, the time sufficient to reduce parasitic nematode (worm) burden on pasture
may be at least one week, or at least 2 weeks, or at least 3 weeks, or at least 4
weeks, or at least 5 weeks, or at least 6 weeks, or at least 7 weeks, or at least
8 weeks, or at least 9 weeks, or at least 10 weeks, or in the range of 1 to 26 weeks,
or 1 to 15 weeks, or 1 to 10 weeks, or 1 to 8 weeks, or 1 to 6 weeks, or 1 to 5 weeks,
or 1 to 4 weeks, or 1 to 3 weeks, or 2 to 15 weeks, or 2 to 10 weeks, or 2 to 8 weeks,
or 2 to 6 weeks, or 2 to 5 weeks, or 2 to 4 weeks, or 2 to 3 weeks. Preferably, the
time sufficient to reduce parasitic nematode (worm) burden on pasture may be in the
range of 2 to 26 weeks. In one embodiment of the invention, the time may be in the
range 12 to 20 weeks, and in particular 12 to 16 weeks.
[0049] It is contemplated that the composition of the invention may be administered for
any length of time, even after the parasitic nematode (worm) burden on pasture is
reduced. For example, the composition may be administered for at least one week, or
can be continued indefinitely.
[0050] It will also be apparent to the skilled artisan that an amount sufficient to reduce
parasitic nematode (worm) burden on pasture according to the composition for use of
the invention may be an amount of viable
D. flagrans spores contained in the composition that is administered to the grazing animal and
will vary according to the animal's weight, and will be determined by the user or
their technical advisors.
[0051] In one embodiment, according to the composition for use of the invention, the amount
administered may comprise viable
D. flagrans spores of at least about 1 × 10
3 viable spores per Kg bodyweight of the grazing animal per day. In another embodiment,
according to the composition for use of the invention, the amount administered may
comprise viable
D. flagrans spores in the range of
1 × 103 to 5 × 108 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 108 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 108 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 107 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 107 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 107 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 106 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 106 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 106 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 105 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 105 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 105 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 5 × 104 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 2.5 × 104 viable spores per Kg bodyweight of the grazing animal per day, or
1 × 103 to 1 × 104 viable spores per Kg bodyweight of the grazing animal per day.
[0052] For example, according to the composition for use of the invention, the amount administered
may comprise viable
D. flagrans spores of
about 1 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 1.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 2 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 2.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 3 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 3.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 4 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 4.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 5.5 × 104 viable D. flagrans pores per Kg bodyweight of the grazing animal per day, or
about 6 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 6.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 7 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 7.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 8 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 8.5 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 9 × 104 viable D. flagrans spores per Kg bodyweight of the grazing animal per day, or
about 1 × 105 viable D. flagrans spores per Kg bodyweight of the grazing animal per day.
[0053] Preferably, according to the composition for use of the invention, the amount administered
may comprise about 1 × 10
4 to 1 × 10
5 viable
D. flagrans spores per Kg bodyweight of the grazing animal per day. More preferably, the amount
administered may comprise about 1 × 10
4, about 3 × 10
4 or about 1 × 10
5 viable
D. flagrans spores per Kg bodyweight of the grazing animal per day. Most preferably, the amount
administered may comprise about 3 × 10
4 viable
D. flagrans spores per Kg bodyweight of the grazing animal per day. I
[0054] In another aspect, the present invention provides the composition for use of the
invention administered as part of an integrated parasite management program (IPM)
for controlling the spread of a parasitic nematode of grazing animals, wherein the
IPM program comprising the following:
- a) Treating the grazing animal with an anthelmintic effective against the parasitic
nematode;
- b) Transferring the grazing animal to a clean pasture, if possible, which is minimally
infected by or free of larvae of the parasitic nematode; and
- c) Administering the composition of the invention to the grazing animal.
[0055] It will be clear to the skilled addressee that any anthelmintic useful in treating
the parasitic nematode may be used in treating the grazing animal. In particular,
for example, abamectin, ivermectin, pyrantel pamoate and pelletierine sulphate are
useful anthelmintics in the present invention. Following the introduction of phenothiazines
in the 1950's, the control of gastrointestinal parasites has been achieved using chemical
anthelmintics and predominantly relies on the treatment with broad-spectrum parasiticides
belonging to three main chemical classes: the benzimidazoles (BZ), the macrocyclic
lactones (ML) and the imidazothiazoles/tetrahydropyrimidines (LV). Although some anthelmintics,
including derquantel (spiroindole) and monepantel (an amino-acetonitrile derivative,
AAD) have been developed, success in the discovery of novel anthelmintics has been
limited over the last two decades. The above anthelmintics may be administered as
a combination of one or more thereof. Suitable dosages of the anthelmintic will be
clear to the skilled addressee and will depend on the usual parameters such as the
nature of the anthelmintic, the animal species, the animal's bodyweight, the animal
or group's chemical resistance status and climatic conditions etc.
[0056] It will be apparent to the skilled artisan that a clean pasture at b) of the previous
aspect may be prepared according to any method. Preferably, if possible, the clean
pasture at b) is prepared by not grazing the pasture with the same species for a period
of about 6 weeks or more.
[0057] It will be understood by the skilled addressee that "biological control" means the
control of a pest by the introduction of a natural enemy or predator.
[0058] In the context of the present invention, the term "biological control composition"
includes, but is not limited to, agricultural biopesticides, veterinary biochemicals,
feed additives, and products useful for agricultural pest control.
[0059] Consistent with the examples and text of the present application, the skilled addressee
will understand that in the context of the present invention when reference is made
to the singular form of a noun eg. a spore, the plural is also contemplated. Specifically,
for example, a composition comprising a spore includes a composition comprising many
spores. As a further example, reference to treatment of an animal includes treatment
of a herd or flock of animals or any other collective group.
[0060] The term "grazing animal" according to any aspect, example, or embodiment herein
includes any exotic (nondomestic) or domestic grazing animal and includes but is not
limited to both exotic (nondomestic) and domestic ruminants. For example, the domestic
grazing animal is selected from the group consisting of, but not limited to, horse,
goat, sheep, cattle, deer and camelids (such as alpacas and llamas). In another example,
the nondomestic or exotic animal is selected from species of artiodactylids including
but not limited to giraffe, antelope, deer, oryx, sable antelope, blackbuck, bongo,
okapi and wildebeest. Preferably, the exotic animal according to the invention is
one that is held in captivity within an enclosure, e.g., in a zoological facility.
In another example the grazing animal is selected from animals including, but not
limited to, monograstric, ruminant, camelid and pseudo-ruminant animals (domestic
or non-domestic or exotic). In another example, the grazing animal is selected from
domestic or wild animals.
[0061] It will also be understood that the term "parasitic nematode" according to any aspect,
example, or embodiment herein includes any parasitic nematode that is known, or subsequently
discovered to infect a grazing animal. For example the parasitic nematode is any one
or more of a nematode of the
Stronglyus spp., Cyathostomum spp., Triodontophorous spp., Trichonema spp., Oesophagodontus
spp., Gyalocephalus spp., Cylicocylus spp., Cylicodonotophorus spp., Cylicostephanus
spp., Gongylonema spp., Habronema spp., Mecistocirrus spp., Oxyuris spp., Parascaris
spp., Skrjabinema spp., Strongyloides spp., Toxocara spp., Dictyocaulis spp., Muellerius
spp., Protostrongylus spp., Onchocerca spp., Parafilaria spp., Setaria spp., Stephanofilaria
spp., Thelazia spp., Trichostrongylus spp., Cooperia spp., Bunostomum spp., Teladosagia
spp., Oesophagostomum spp., Nematodirus spp., Haemonchus spp., Chabertia spp., Trichuris
spp., and/or
Ostertagia spp.
[0062] Preferably, the parasitic nematode according to any aspect, example, or embodiment
herein is one or more of Barber's Pole Worm or Wire Worm (
Haemonchus spp.), Hairworm or Stomach Hairworm
(Trichostrongylus spp), Intestinal Worm or Small Intestinal Worm (
Cooperia spp.) and Hookworm (
Bunostomum spp.), Black Scour Worm
(Trichostrongylus spp.), Small and Medium Brown Stomach Worm (
Teladosagia (Ostertagia) spp.), Nodule Worm (
Oesophagostomum spp.), Stomach Hair Worm (
Trichostrongylus spp.), Thread Worm (
Strongyloides spp.), Large Mouthed Bowel Worm (
Chabertia spp.), Whipworm (
Trichuris spp.), Thin Necked Intestinal Worm or Thread Necked Worm (
Nematodirus spp.), Redworms or Large Strongyles (including
Strongylus spp.,
Triodontophorus spp.and
Oesophagodontus spp.) and/or Cyathostomes / Small Strongyles (including
Cyathostomum spp.,
Trichonema spp.,
Gyalocephalus spp.,
Cylicocyclus spp.,
Cylicodontophorus spp. and
Cylicostephanus spp.), Ascarids (
Parascaris spp.) and Pinworms (
Oxyuris spp.).
[0063] In one or more embodiments, the composition and use thereof of the present invention
provides the following advantages:
- D. flagrans IAH 1297, is not absorbed by the host animal.
- D. flagrans IAH 1297, survives passage through the gut and into the manure.
- D. flagrans IAH 1297, remains in the spore form as a chlamydospore until environmental conditions
are suitable coinciding with the nematodes becoming active, then germinating in the
manure where the worm larvae are trapped, paralysed and consumed.
- D. flagrans IAH 1297, contains low or no undesirable metabolites. It has very low levels of flagranone
A, undetectable levels of flagranone B and undetectable levels of flagranone C. Hence
the organism falls below the current European safety thresholds for such substances.
- Used according to the present invention, D. flagrans IAH 1297, effectively breaks the worm life cycle.
- D. flagrans IAH 1297, used according to the present invention is effective against anthelmintic-resistant
and multi-resistant worms.
[0064] Unless the context clearly requires otherwise, throughout the description and the
claims, the words 'comprise', 'comprising', and the like are to be construed in an
inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in
the sense of "including, but not limited to".
[0065] Throughout this specification, unless specifically stated otherwise or the context
requires otherwise, reference to a single step, composition of matter, group of steps
or group of compositions of matter shall be taken to encompass one and a plurality
(i.e. one or more) of those steps, compositions of matter, groups of steps or group
of compositions of matter.
[0066] Each aspect, embodiment and/or example of the invention described herein is to be
applied
mutatis mutandis to each and every aspect, embodiment and/or example unless specifically stated otherwise.
[0067] Those skilled in the art will appreciate that the invention includes all of the steps,
features, compositions and compounds referred to or indicated in this specification,
individually or collectively, and any and all combinations or any two or more of said
steps or features.
[0068] The present invention is not to be limited in scope by the specific embodiments described
herein, which are intended for the purpose of exemplification only. Functionally-equivalent
products, compositions and methods are clearly within the scope of the invention,
as described herein.
List of Abbreviations:
[0069]
GIN - Gastrointestinal nematodes
EP - End User product
MP - Mill Product
TGAI - Technical Grade Active Ingredient
LOQ - Limit of quantitation
LOD - Limit of detection
HPLC - high performance liquid chromatography
UV - ultraviolet
IPM - Integrated Pest Management
FEC - Faecal Egg Count
FECRT - Faecal Egg Count Reduction Test
FLC - Faecal Larval Cultures
Brief Description of the Drawings
[0070]
Figure 1: Schematic diagram showing the basic lifecycle of gastrointestinal nematodes
in grazing animals.
Figure 2: Schematic diagram showing the development of chemical resistance. The diagram
indicates the year of introduction of various chemicals and R denotes the year of
first recorded resistance Waller, P.J., Acta Tropica 56(1994)233-243. Antimicrobials: SULHPA; sulphonamides, PEN, penicillin; STREP, streptomycin. Insecticides:
DDT, dicophane; CYCLO, cyclodienes; OP, organophosphates; SP, synthetic pyrethroids.
Fungicides: AH, aromatic hydrocarbons; DOD, dodine; BZ, benzimidazoles; DCB, dicarboxamides.
Anthelmintics: BZ, benzimidazoles; LEV, levamisole; AVM, avermectins.
Figure 3: Schematic diagram showing a nematode larva captured by D. flagrans. The larva is captured in a sticky net consisting of a number of strong arcs. At the
contact part, the parasite body is penetrated whereby the fungal hyphae extend out
to grow and fill the body of the nematode to effectively kill the nematode. Inner
organs are eventually dissolved and absorbed. The dotted lines show the fungal mycelium
inside the parasite.
Figure 4a: Method for measuring faecal egg count (FEC).
Figure 4b: Method for faecal egg count reduction test (FECRT)
Figure 5: Product information for Livamol®
Figure 6: Graphical representation of cattle field trial results (Cattle Trial 1)
using the composition of the invention as described in Example 7 and Table 3.
Figure 7: Graphical representation of cattle field trial results (Cattle Trial 2)
using the composition of the invention as described in Example 7 and Table 3.
Figure 8: Graphical representation of goat field trial results (Goat Trial 1) using
the composition of the invention as described in Example 7 and Table 3.
Figure 9: Graphical representation of goat field trial results (Goat Trial 2) using
the composition of the invention as described in Example 7 and Table 3.
Figure 10: Graphical representation of goat field trial results (Goat Trial 3) using
the composition of the invention as described in Example 7 and Table 3.
Figure 11: Graphical representation of horse field trial results (Horse Trial 1) using
the composition of the invention as described in Example 7 and Table 3.
Figure 12: Graphical representation of horse field trial results (Horse Trial 2) using
the composition of the invention as described in Example 7 and Table 3.
Figure 13: Graphical representation of horse field trial results (Horse Trial 3) using
the composition of the invention as described in Example 7 and Table 4.
Figure 14: Graphical representation of sheep field trial results (Sheep Trial 1) using
the composition of the invention as described in Example 7 and Table 4.
Figure 15: Graphical representation of sheep field trial results (Sheep Trial 2) using
the composition of the invention as described in Example 7 and Table 4.
Figure 16: Graphical representation of sheep field trial results (Sheep Trial 3) using
the composition of the invention as described in Example 7 and Table 4.
Figure 17: Graphical representation of sheep field trial results (Sheep Trial 4) using
the composition of the invention as described in Example 7 and Table 4.
Detailed Description of Preferred Embodiments
[0071] The present invention will now be described in more detail with reference to specific
but non-limiting examples describing specific compositions and methods of use. It
is to be understood, however, that the detailed description of specific procedures,
compositions and methods is included solely for the purpose of exemplifying the present
invention. It should not be understood in any way as a restriction on the broad description
of the inventive concept as set out above.
EXAMPLE 1
Isolation, culturing and characterisation of D. flagrans
[0072] The inventors sought to identify a
D. flagrans isolate that would be useful for further work in development of a composition or
biological control product. Without being bound to any particular theory, it is desirable
that a suitable isolate exhibits relatively rapid and abundant growth, produces large
quantities of chlamydospores for ease of scale-up, has a high predatory ability for
maximum effectiveness on release, ease of monitoring on release as a biological control
agent, has no negative effects on non-target organisms.
[0073] Twenty-five isolates were examined and
D. flagrans IAH 1297 was found to have good growth rate, and chlyamydospore production, a high
trapping efficiency and good growth on a grain substrate compared to the others. Based
on these characteristics, the
D. flagrans IAH 1297 isolate was deposited at National Measurement Institute, 1/153 Bertie Street,
Port Melbourne, Victoria 3207, Australia on 2 August 2016 in accordance with the Budapest
Treaty requirements.
[0074] By way of non-limiting example only, the following assays were used to determine
these parameters.
Fungal Isolates
[0075] Fungal isolates were obtained from original cultures derived from a field survey
to detect the presence of nematophagous fungi in faecal, compost and soil samples
according to procedures as described in
Larsen et al., 1994 (Veterinary Parasitology 53:275-281) and subsequent additions to the CSIRO culture collection. Subcultures were taken
from parent stock and maintained on Potato Dextrose Agar (PDA) for purity and viability
using the procedure outlined below.
Culturing Procedure
[0076] Long-term cultures were maintained in 100% PDA McCartney bottle slopes. These were
prepared using commercially available PDA Difco
™ according to the manufacturer's instructions. 10 mL of PDA mixture was then dispensed
into McCartney bottles. Lids were loosely placed on bottles and autoclaved at 121°C
for 21 min. While still hot, lids were tightened and bottles placed on a 45° angle
and then allowed to cool and solidify. Spore inoculum was then transferred from parent
cultures to the McCartney bottle agar surface using a sterile bacterial loop. The
McCartney bottles were labelled in accordance with media type, fungal culture ID and
date of inoculation, and stored in a refrigerator at 4°C for future use.
[0077] Short-term cultures derived from the long-term cultures, were maintained on PDA plates
(6 cm diameter). Potato dextrose agar was prepared as above and autoclaved in the
1 L pyrex bottle at 121°C for 21 minutes. While still hot, 2 mL of antibacterial agent
ENGEMYCINO (which contains 100 mg/mL of oxytetracycline hydrochloride) was added to
the agar and mixed by inverting. Plates were then poured in a Laminar flow cabinet
ensuring complete coverage of petri dish to a depth of approximately 6 mm. These were
then allowed to cool and solidify before storage at 4°C until use. Using a sterile
surgical blade, 3 mm × 3 mm sections of agar containing the fungal culture were cut
and placed in the centre of a new PDA plate. Plates were then sealed with Parafilm
® to prevent desiccation and were incubated at 27°C for 7 - 10 days. Plates were labelled
with fungal ID and dated.
Temperature
[0078] D. flagrans isolates were evaluated. Five constant temperature regimes were tested: 12°C, 17°C,
22°C, 27°C and 32°C. Three replicate 1% Potato-Dextrose Agar (PDA) plates for each
treatment (6 cm diameter) were inoculated with 2 mm × 2 mm agar plugs cut with a sterile
scalpel blade from the colony margin of 1-2 week old fungal cultures grown on 1% PDA
and placed in the centre of the test agar plates. Each treatment was incubated for
14 days (or days otherwise indicated herein below) in a Gallenkamp controlled temperature
incubator that had been calibrated to the desired temperature. Throughout the experiments
the temperature within each cabinet varied by +/- 2°C. Radial growth measurements
and chlamydospore enumeration was calculated daily.
Radial Growth
[0079] Radial growth was measured daily under a stereo dissecting microscope at 10 X magnification.
Radial growth was calculated by measuring the distance (mm) from the edge of the agar
plug to the edge of the mycelial growth twice in opposite directions. One of these
directions was chosen randomly. Growth rate was calculated over the number of days
it took for the mycelia to reach the outer perimeter of the plate.
Chlamydospore Enumeration
[0080] Chlamydospore numbers were determined daily by placing a 6 cm
2 grid divided into 2 mm
2 squares beneath the agar plate under a stereo dissecting microscope at 10 X magnification.
The grid contained five randomly marked 2 mm
2 squares that were approximately 12-14 mm from the centre plug and the chlamydospore
numbers in these five areas were counted and the number of chlamydospores per cm
2 was calculated.
Statistical Analysis
[0081] Analysis of variance with Tukey's post hoc testing using Statgraphic software (Statgraphics
Centurion XV, 2006) was performed at each temperature to assess the differences between
the number of days taken to reach the perimeter of the petri dish and also to determine
differences between the rate of growth between the isolates. The same process was
used to determine the differences between the rate of spore production between the
isolates, in addition to the number of days taken to the first spore production.
Trapping Efficiency
Fungal inoculum for measurement of trapping efficiency
[0082] Fungal isolates of
D. flagrans were obtained from original cultures derived from a field survey (
Larsen et al., 1994 Veterinary Parasitology 53:275-281), and subsequent additions to the CSIRO. Subcultures were taken from parent stock
and maintained on Potato Dextrose Agar (PDA) using the procedure outlined above. The
spore material used was grown on barley substrate as outlined below in Example 2 and
added to faecal cultures at a concentration of 1 × 10
6 chlamydospores/g of faeces.
Faecal cultures
[0083] Faecal material was collected from worm-free and
Trichostrongylus colubriformis infected sheep kept in the CSIRO animal house at F.D. McMaster Laboratory-Chiswick,
Armidale, NSW, for the purpose of maintaining helminth stocks. Faeces were collected
in a bag attached to the rear end of the sheep by a faecal collection harness and
left overnight. Sheep were fed 800 g/day feed pellets with a composition of (g/kg):
lucerne 500, wheat 100, pollard 200, bran 175, salt 20 and ammonium chloride 5. Worm
infected sheep were infected with a single oral dose of 20,000 third stage
7. colubriformis larvae. Infected sheep were dosed weekly with 0.25-0.5 mg per 10 kg of the corticosteroid
"Ilium Trimedexil
©, Troy Laboratories Pty Ltd" by intramuscular injection, to partially suppress the
immune system to help maintain worm infection.
[0085] Twenty-five grams of faeces was mixed in Styrofoam cups with approx 7-10 g vermiculite
(depending on initial faecal consistency) to create a moist crumbly texture and this
sheep faecal mix was then transferred to 500 g culture jars (M.R. Knox
pers. comm.)
. For each isolate, five replicate culture jars were used and chlamydospores of the
isolate were added to each of the replicate culture jars containing the sheep faecal
mix. After thorough mixing, the faecal mix was then lightly compressed to create an
even consistency. Approximately 10 mL of distilled water was then added to each jar
to maintain humidity. Five replicate control cultures were similarly prepared without
the addition of spore material. The culture jars were then incubated at 20°C for 10
days.
[0086] After incubation, culture jars were filled with distilled water and a 20 cm diameter
petri dish was placed on the top of the jar. Jars were then inverted, the petri dish
half filled with distilled water and left at room temp for 48 hrs. All third stage
larvae (L3) were then collected by decanting the water from the Petri dishes into
50 mL collection tubes and made up to a volume of 50 mL. Formalin was added at final
concentration of 1-2 % and then the 50 mL larval solution was heated at 55- 57°C for
approximately 1 min to kill the larvae (
Van Wyk et al. 2004 Veterinary Parasitology 119:277-306). Larvae were enumerated by taking 5 replicate 100 µL aliquots of each sample on
a microscope slide and counting under 100x magnification. If the larvae counted was
less than 10 per 100 µL aliquot, then the larvae were left to settle for a minimum
of 3 hrs before siphoning off excess liquid, concentrating to a volume of 5 mL, before
enumeration was repeated as described.
EXAMPLE 2
Solid substrate fermentation method/analysis
[0087] By way of non-limiting example only,
D. flagrans may be produced using the following solid substrate fermentation method.
Preparation of liquid inoculum for grain substrates
[0088] Liquid broth was made using 1 % yeast extract, 0.5 % KH
2PO
4, 0.1 % NaNO
3, 0.05 % MgSO
4.7H
2O and 2 % soluble starch. The pH was adjusted to 6.5 using 0.1M HCl and sterilised
in an autoclave under standard liquid conditions. The broth was then left to cool
to approximately 25°C. Once cool, 250 mL of broth contained in a 1.5 L conical flask,
was inoculated with 8 equal pieces of a ¼ (10 cm diameter) plate of a 7 day PDA culture
of D.
flagrans and incubated on an orbital shaker at 200 rpm for 7 days at 28°C.
Solid substrate preparation and fermentation
[0089] For each substrate, triplicate 50 g grain samples were weighed into 250 mL Erlenmeyer
flasks. The samples were then moistened with water at a rate of 1/3 of the total volume
required to achieve substrate moisture of 40 % (See Figures 3.1, 3.2 and 3.3) and
mixed thoroughly. Samples were left standing at room temperature overnight (16 hrs).
After 16 hrs, the flasks were plugged with cotton wool and covered with foil. The
flasks were then autoclaved under standard liquid conditions. The flasks were then
transferred to a laminar flow cabinet and cooled to room temperature. Once cool, the
flasks were inoculated with the final volume of liquid inoculum to achieve 40 % substrate
moisture using sterilised measuring cylinders. In the case of millet, this was 24
mL of liquid inoculum; for lupins it was 24 mL of liquid inoculum plus 1 mL of sterile
H
2O; and for barley it was 24 mL of liquid inoculum plus 4 mL of sterile H
2O. The addition of sterile H
2O to the inoculum for lupins and barley was to ensure each flask had an equal amount
of fungal inoculum added while maintaining the substrate moisture at 40 %. Inoculated
cultures were allowed to stand before being gently mixed after 24 hrs to ensure that
all free moisture had been absorbed by the grains. After one week's incubation, substrates
were broken up by vigorously shaking flasks. They were further incubated for 25 days
at 20°C.
Drying Procedure
[0090] After incubation, fermented grains were broken up by thorough shaking in the flask.
In the laminar flow cabinet, the fermented grains were then transferred to small,
shallow Styrofoam trays, combining the replicate cultures once it was determined that
there was no contamination. Remaining substrate clumps were aseptically broken up.
Cultures were dried for 10 days in a room with controlled temperature set at 22°C
to achieve a moisture content of <10 % (as determined by oven moisture analyses of
a 5 g sub-sample after drying for 2 hrs at 130°C). Periodic, gentle agitation of the
trays during this drying period ensured rapid and even drying. The dried samples were
stored in tightly capped 250 mL screw cap containers at 20°C for subsequent analysis.
Chlamydospore Enumeration
[0091] After drying, the samples were ground using a pre-cleaned coffee grinder. Triplicate
0.1 g samples of dried and ground cultures were weighed into 50 mL digestion tubes.
Samples were digested for 72 hrs with constant shaking in an iso-tonic saline solution
containing 1 % pepsin (1:2500 Pepsin A; Sigma chemicals, Sydney) and 1.7 % hydrochloric
acid (AR grade). Chlamydospores were counted using a Spencer Brightline
™ haemocytometer and the spore yield calculated as chlamydospores per gram of dried
and ground culture material.
Viability assessment - MTT staining procedure
[0092] From the above samples, 5 g of ground spore material was suspended in 50 mL of sterile
10 mM potassium phosphate buffer (pH 6.9). This suspension was used for plate analysis.
Triplicate 1.0 mL aliquots of the diluted spore suspension were dispensed into 5 mL
vials. To each vial 1.0 mL of filter sterilized 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT) (2 mg/ mL) and 2 µL 2.5 mM of cobalt chloride solution was added. Vials
were tightly capped and incubated at 27°C for 24 - 36 hrs. After incubation the viable
spores were counted using a haemocytometer. Viable spores stain red or blue through
blue/black and non-viable spores do not stain. Only spores showing complete cytoplasmic
staining were counted as viable (
Meier and Charvat, 1993 American Journal of Botany 80:1007-1015).
Statistical analysis
[0093] The differences in viable spores/g were estimated using ANOVA and Tukey's post hoc
testing (Statgraphics Centurion XV., 2006).
EXAMPLE 3
Production scale-up for commercial application
[0094] By way of non-limiting example only, the
D. flagrans of the composition according to any aspect, embodiment or example herein may be scaled-up
for commercial application as follows. Below, in the context of the present non-limiting
examples, the following terms are used:
Technical Grade Active Ingredient (TGAI): this refers to the dried raw material comprising
chlamydospores of D. flagrans strain IAH 1297, which is the product of the method described in the present example,
Example 3. Typically, this product would contain 1 × 106 or more viable spores per gram.
End-user Product (EP): this refers to a product comprising TGAI blended with feed
ingredients including, but not limited to, protein meals, oils, fats, carbohydrates,
antioxidants, preservatives, vitamins, minerals and colourants. EP is intended for
use by farmers as an animal feed supplement or for mixing into animal feed.
Mill Product (MP): this refers to a product comprising TGAI blended with feed ingredients
including, but not limited to, protein meals, oils, fats, carbohydrates, antioxidants,
preservatives, vitamins, minerals and colourants. MP is intended for sale to third-party
manufacturers, such as but not limited to, feed mills, veterinarians or others that
may use it as an ingredient in their own branded products including animal feed supplements
and feeds. In the context of the present non-limiting example, MP comprises about
15x more TGAI than EP.
Purified TGAI: this refers to a product derived from TGAI in which the density of
D. flagrans chlamydospores is increased relative to the TGAI from which it is derived.
[0095] A dried spore concentrate was produced. As indicated above, the dried spore concentrate
was called the Technical Grade Active Ingredient (TGAI). The TGAI was produced as
follows:
- a. The D. flagrans was grown using a standard solid substrate fermentation method as in Example 2. The
D. flagrans was grown on a moistened wholegrain; additional growth media was added, containing
an energy source, a nitrogen source, as well as nutrients;
- b. The production process is a 2-step process comprising sterilizing the moistened
grain by heat or gamma irradiation, inoculating the moistened grain with liquid broth
containing the fungus and possibly including some or all of the constituents listed
at (a). Inoculation is performed under sterile conditions and fermentation is allowed
to take place over several weeks, typically about 4 weeks. The fermentation step is
carried out at a controlled temperature of 20-28 degrees Centigrade and the moisture
content varies from as low as 20% to about 40 to 60% moisture. During the fermentation
step, spores develop naturally, specific initiation methods for inducing spore formation
are not being used at this stage.
- c. There are currently two types of fermentation processes used. In one process, stainless
steel trays are used to contain the growth substrate and air or oxygen is circulated
in the headspace during fermentation. In the other process, the growth substrate is
contained in pillow packs that comprise a plastic pouch with a breathing strip, and
the fermentation process is allowed to take place on a shelf, thus no forced circulation
of air or oxygen is used. The fermentation process is designed to exclude the introduction
of foreign organisms and to allow the escape of carbon dioxide and ingress of air.
- d. The second step comprises drying the fermented grain by exposure to air. This is
done as rapidly as possible at low temperature to a moisture content of less than
10%. The spores of D. flagrans are not separated from the grain because the D. flagrans produces spores that are an integral part of the grain. Once dried, the grain including
the spores produce the raw material of spore concentrate. The spore concentrate contains
dried mycelium including spores. The viable count of viable spores per gram obtained
ranges between 1 × 105 to 1 × 1010 spores/g.
- e. On completion of drying the product (TGAI) is packed into sealed bags, packaged
and shipped for further manufacture.
EXAMPLE 4
End-user Product (EP) and Mill Product (MP)
[0096] By way of non-limiting example only, the TGAI was prepared as described in Example
3 and formulated to provide a composition according to the invention. Two products
were prepared, an End-user Product (EP) and a Mill Product (MP) as described above.
[0097] As indicated above, to produce the EP and MP, the TGAI was blended with feed ingredients
including, but not limited to, ingredients comprising protein meals, oils, fats, carbohydrates,
antioxidants, preservatives, vitamins, minerals and colourants. In the present, non-limiting
example, MP comprises about 15x or more TGAI than the EP. After blending, the mixture
was milled to break-down the spore granules to ensure homogeneity. The finished products
were packaged in bags or bulk containers. Typically, the products (both EP and MP)
provide a minimum of 3 × 10
4 viable spores per Kg bodyweight per day when in use (as measured for example in the
viability method in Example 5).
EXAMPLE 5
Faecal egg count test (FEC) test
[0098] Methods for faecal egg counting (FEC) are well known in the art. Examples of techniques
are widely available. An example of instructions for FEC is provided in Figure 4a.
The skilled addressee will be aware of many other sources of methodologies.
EXAMPLE 6
Faecal egg count reduction test (FECRT)
[0099] Methods for faecal egg count reduction test (FECRT) are well known in the art. Examples
of techniques are widely available. An example of instructions for FECRT is provided
in Figure 4b. The skilled addressee will be aware of many other sources of methodologies.
EXAMPLE 7
[0100] By way of non-limiting example only, efficacy trials were conducted with the composition
of the invention. The composition of the invention was prepared for example, according
to Example 3 and further formulated to produce EP according to Example 4.
[0101] A series of placebo-controlled trials in cattle, sheep, goats and horses were conducted
according to VICH (International Cooperation on Harmonisation of Technical Requirements
for Registration of Veterinary Medicinal Products) Good Clinical Practice (GCP) in
different Australian regional locations and seasons to evaluate the ability of the
EP to reduce larval development and migration from faeces onto pasture.
[0102] Briefly, for the short-term trials with cattle, goats and horses, faeces were collected
from the trial animals prior to treatment and placed on a pasture site (Control faeces).
The same animals were then treated with the EP and faeces again collected after about
1 week (Treated faeces). These faeces were then also placed onto pasture sites. At
2 weekly intervals (from 2 through 8 weeks post treatment) samples from the pasture
around randomly-selected faecal pats (Treated and Control) faecal samples were collected
and examined for nematode larvae. The larvae found were then distinguished to species
(as parasitic larvae for the host species involved) and the total parasite larval
numbers for each sample were calculated. The treatment effect was measured by comparing
the pasture larval counts of the two groups (Treated vs. Control).
[0103] For the long-term grazing studies in sheep, two groups of worm-infested sheep were
grazed on separate paddocks, one group receiving EP and the other a placebo. The effect
of treatment on the larval infectivity on the pasture was measured by co-grazing with
groups of worm-free tracer lambs and the treatment effect was measured by comparing
total worm counts of the two groups of tracers.
[0104] Worm species encountered in these studies included those shown in Table 2 below.
Table 2. Worm species encountered in EP (containing chlamydospores of D.
flagrans strain IAH 1297) efficacy trials
| Worm type |
Cattle |
Sheep |
Goats |
Horses |
| Cooperia spp. |
X |
X |
|
|
| Cyathostomes |
|
|
|
X |
| Haemonchus spp. |
X |
X |
X |
|
| Nematodirus spp. |
|
X |
X |
|
| Oesophagostomum spp. |
X |
|
X |
|
| Ostertagia spp. |
X |
|
|
|
| Strongylus spp. |
|
|
|
X |
| Teladorsagia spp. |
|
X |
X |
|
| Trichostrongylus spp. |
X |
X |
X |
X |
[0105] Statistically-significant reductions (P<0.05) in total worm count in the tracer lambs
were obtained in each of the sheep trials. For the cattle, goat and horse studies,
the pooled data for each animal species were analysed, showing that the treatment
effect was significant at P≤0.01 in each case, as shown below.
[0106] The studies with EP summarised below were conducted according to VICH GL9 GCP (June
2000) and World Association for the Advancement of Veterinary Parasitology (WAAVP)
Guidelines for evaluating the efficacy of anthelmintics in ruminants.
Short term efficacy studies with feed supplement (EP) (cattle, horses and goats)
[0107] A series of placebo-controlled trials were conducted to evaluate the ability of EP
to reduce larval development and migration from faeces on pasture in cattle, horses
and goats.
[0108] In these trials the following products were used:
- 1. Livamol®: Placebo Product (see Product description at Figure 5) - a nutritious animal feed
supplement manufactured by International Animal Health Products Pty Ltd, referred
to as "Livamol®" below.
- 2. EP - comprising TGAI dispersed in Livamol® and referred to as "EP" below.
[0109] Briefly, the selected trial animals harboured a variety of parasitic nematodes, including
anthelmintic-resistant strains, in some cases these were augmented via artificial
infection. The animals were fed Livamol
® for about 1 week prior to collection of their faeces, which were then manually placed
on a pasture at the trial site(s) (Control faeces). The same animals were then treated
with EP (providing minimum 3 × 10
4 viable chlamydospores of D. flagrans/kg bodyweight/day for about 1 week) and faeces
again collected and placed onto pasture as above at the same sites (Treated faeces).
At 2 weekly intervals (from 2 through 8 weeks post treatment) pasture samples from
around the randomly-selected deposited faecal samples were collected and examined
for nematode larvae. The larvae found were then distinguished into species (as parasitic
larvae for the host species involved) and the total parasite larval numbers for each
sample was calculated. The action of
D. flagrans in the faecal pats of EP-treated faeces was evidenced in the reduced numbers of larvae
found on the surrounding pasture.
[0110] Studies summarised below were conducted according to VICH GL9 GCP (June 2000) and
WAAVP Guidelines for evaluating the efficacy of anthelmintic in ruminants. Results
are summarised in Table 3 and in Figures 6 to 13.
Table 3. Overview of efficacy trials on supplementation with EP to reduce larval development
and migration from faeces on pasture in cattle, goats and horses.
| Speci es |
Number of animals |
Dura tion of treat men t (day s) |
Locatio n |
Season |
Result (% reductio n of larval emergen ce weeks 2-8) |
Study Reference |
| Cattle |
6 |
6 |
Armidale NSW |
Spring |
75 |
Cattle Trial 1 |
| Cattle |
6 |
6 |
Nimmita bel NSW |
Spring |
75 |
Cattle Trial 1 |
| Cattle |
6 |
7 |
Armidale NSW |
Autumn |
82 |
Cattle Trial 2 |
| Cattle |
6 |
7 |
Dayboro QLD |
Autumn |
88 |
Cattle Trial 2 |
| Goat |
6 |
7 |
Armidale NSW |
Spring |
85 |
Goat Trial 1 |
| Goat |
6 |
7 |
Nimmita bel NSW |
Spring |
8* |
Goat Trial 1 |
| Goat |
12 |
9 |
Armidale NSW |
Autumn |
81 |
Goat Trial 2 |
| Goat |
12 |
9 |
Dayboro OLD |
Autumn |
99 |
Goat Trial 2 |
| Goat |
12 |
7 |
Dayboro QLD |
Spring/Sum mer |
80 |
Goat Trial 3 |
| Goat |
12 |
7 |
Nimmita bel NSW |
Spring/Sum mer |
98 |
Goat Trial 3 |
| Horse |
5 |
7 |
Armidale NSW |
Autumn |
94 |
Horse Trial 1 |
| Horse |
6 |
5 |
Armidale NSW |
Spring |
97 |
Horse Trial 2 |
| Horse |
6 |
5 |
Nimmita bel NSW |
Spring |
53 |
Horse Trial 2 |
| Horse |
6 |
5 |
Armidale NSW |
Autumn |
65 |
Horse Trial 3 |
| Horse |
6 |
5 |
Dayboro QLD |
Autumn |
94 |
Horse Trial 3 |
| *Trial site affected by freezing conditions shortly after deposition of faeces. |
[0111] Statistical analysis (Groves, P 2015) shows that the treatment effect was statistically
significant (p≤0.01) for all species (See Example 7).
[0112] In the cattle trials the nematode types encountered were
Cooperia spp.,
Trichostrongylus spp.,
Oesophagostomum spp.,
Ostertagia spp. and
Haemonchus spp, including multi-resistant strains.
[0113] In goats the nematodes were
Teladorsagia spp.,
Trichostrongylus spp.,
Nematodirus spp.,
Haemonchus spp. and
Cooperia spp. including multi-resistant strains. Goats were also challenged with a mixture
of gastrointestinal strongyle larvae, including known multi-resistant strains of
Haemonchus contortus, Trichostrongylus colubriformis and
Teladorsagia circumcincta and recent field isolates of
Cooperia spp. and
Nematodirus spp.
[0114] In horses the dominant species were cyathostomes, however some
Strongylyus spp. and
Trichostrongylus axei were also present.
[0115] The pathogenic genera of gastrointestinal nematode parasites of domesticated livestock
are cosmopolitan in their distribution although differences in prevalence and abundance
occur due to climatic differences. The predominant genera in Australia are represented
in most geographic locations where livestock production occurs throughout the world.
Long term efficacy studies with EP (sheep)
[0116] A series of placebo-controlled trials were conducted to evaluate the ability of the
EP to reduce larval development and migration from faeces on pasture in sheep in a
range of geographic locations and seasons as outlined below.
- 1. Livamol®: Placebo Product - a nutritious animal feed supplement manufactured by International
Animal Health Products Pty Ltd, referred to as Livamol® below.
- 2. EP - comprising TGAI dispersed in Livamol® and referred to as "EP" below or "the test composition".
[0117] In each of these studies the groups of sheep used had different roles:
- (1) "seeder" sheep, which harboured natural infections of a range of parasitic worms
representative of the region (including multi-resistant strains), were used to contaminate
the pasture by dropping faeces bearing worm eggs.
- (2) "tracer" sheep, which were young worm-susceptible animals, free of any worm burden,
which were used to assess the degree of worm-contamination of the pasture on which
they grazed.
[0118] In each trial a pair of matched paddocks was used, where one paddock was grazed with
a group of seeder sheep that received a daily supplement of the placebo (Control Group)
and the other by a matching group that received a daily supplement of EP, providing
a daily dose of minimum viable 3 × 10
4 spores/kg bodyweight (Treatment Group).
[0119] After the seeder sheep had grazed the paddocks for two months, the degree of contamination
of the pasture by infectious nematode larvae was assessed by grazing the paddocks
with worm-susceptible tracers for a period of 3 weeks. One group of tracers grazed
on the Control paddock and a matching group grazed the EP paddock. The tracer animals
were then removed to raised pens to allow their worm burdens to mature and their degree
of infection was determined by conducting a Total Worm Count (TWC) after sacrifice
and gut washing. In three of the trials the seeder sheep continued to graze the trial
paddocks for a further two months at which time another group of tracers were introduced
and their TWC was determined.
[0120] The difference in TWC between the two groups of tracers demonstrated the ability
of EP to prevent the emergence of infectious larvae from the droppings of the seeder
sheep onto the pasture.
[0121] Results are summarised in Table 4 and in Figures 14 - 17. By naturally reducing the
larval infectivity of the pasture, use of EP resulted in significantly lowered worm
burdens for the most clinically-important species of worms encountered in the trials,
including multi-resistant strains.
Table 4 Overview of efficacy trials on supplementation with EP to reduce larval development
and migration from faeces on pasture in sheep
| Species |
Seeder animals |
Location |
Season |
Tracer animals |
Reference |
| |
No. of Animals |
Duration of Treatment |
|
|
No. of Animals* (duration) |
Reduction Total Worm count§ |
|
| Sheep |
20/20 |
57 days |
Armidale NSW |
Summer/ Autumn |
23/23 (21 days) |
57% (Week 14) |
Sheep Trial 1 |
| Sheep |
30/30 |
119 days |
Nimmitabel NSW |
Spring/ Summer |
10/10 (21 days) |
20% (week 11) |
Sheep Trial 2 |
| 57% (week 18) |
| 10/10 (21 days) |
|
| Sheep |
30/30 |
122 days |
Armidale NSW |
Spring/ Summer |
10/10 (21 days) |
26% (week 11) |
Sheep Trial 3 |
| 84% (week 18) |
| 10/10 (21 days) |
|
| Sheep |
30/30 |
125 days |
Gore, QLD |
Summer/ Autumn |
10/10 (21 days) |
74% (week 11) |
Sheep Trial 4 |
| 75% (week 18) |
| 10/10 (21 days) |
|
| *Number of control/treated animals, § arithmetic means # Days of treatment while on
test paddocks |
[0122] The worm genera encountered in these trials includes Haemonchus, Trichostrongylus,
Teladorsagia and Nematodirus.
[0123] Other grazing animals that have been tested wherein EP provided large reductions
in total worm counts include giraffe, antelope, zebra and blackbuck.
[0124] These studies confirm that
D. flagrans of the invention survives gut passage and efficiently traps a wide variety of commercially-significant
nematode parasites of grazing animals including cattle, sheep, horses, goats and zoo
animals. These field studies have confirmed the composition of the invention is suitable
for commercial application to reduce worm infestation on pasture and so manage the
levels of infection in the animals themselves, as well as demonstrating economic benefit
such as reduced disease & mortality, reduced need for use of chemical wormers and
improved performance.
[0125] The required daily dose of
D. flagrans strain IAH 1297 is approximately 10x lower than studies using other strains of
D. flagrans. This represents a significant advantage over other strains of
D. flagrans.
EXAMPLE 8
Statistical analysis of short-term studies of Example 7
[0126] At each time point at each trial site the mean numbers of parasite larvae for all
the Control and test composition samples were calculated. In order to determine the
impact of test composition treatment on larval numbers on pasture across trials, the
data from each site for the multi-site trials were averaged and then, for each species
of animal, the data from all studies were pooled for analysis by time period on pasture
(2, 4, 6, 8 weeks and total for weeks 2-8). From this the overall mean larval numbers
(Control and test composition) at each time point and total for weeks 2-8 were calculated.
[0127] The larval determinations at each time interval were not independent as for each
trial the samples all came from a pooled composite from the same experimental animal.
It is therefore appropriate to consider these are not completely independent and to
use a repeated measure analysis (ANOVA) for comparison of the results. Hence the data
were analysed using Repeated Measure ANOVA, with Non-treated faeces (Control) versus
Treated faeces (test composition) and trial number as the main effect variables. All
interactions were included in the analysis.
Horse Trials
[0128] Three trials were compared, conducted using EP in horses over 5 geographic sites
over 2 seasons. The sites differed between trials so only trial number was used as
a variable in the analysis. The ANOVA results are shown in Table 5.

[0129] Table 5 shows that the effect of treatment with EP over the 8 week observation period
was statistically-significant as was the week of sampling after treatment. There were
significant interactions between the time after treatment and the trial and between
time, trial and treatment.
[0130] Table 6 shows the mean numbers of horse parasite larvae in the pasture samples over
the 8 week trial period for the 3 trials as well as the corresponding overall values.
The overall mean larval count for the Control samples was 2248 larvae compared with
only 363 larvae for the test composition treated samples (P=0.004).

[0131] Figures 11 - 13 show that the burden of horse parasite larvae on pasture increased
with time after placement of the faeces on pasture and this increased faster and maintained
at much higher levels from the Control faeces compared with test composition treated
faeces. Variability was marked across the trials but a significant difference was
observed at 6 weeks post treatment (Table 6). Overall, the total number of larvae
emerging from test composition treated faeces over the 8 week observation period was
significantly reduced compared to the Control faeces (Tables 5 and 6).
[0132] This response varied across the three trials (Figs. 11 - 13) with more larvae found
at 4 weeks post treatment in trial #2529, at 6 weeks in trial #1955 and a slower build
up to a peak at 8 weeks observed in trial #2633. This may have been due to differing
climatic and local conditions at each site.
Conclusions from horse experiments
[0133] Overall, administration of EP to horses significantly (P=0.004) reduced the detection
of horse parasite larvae on pasture surrounding faeces over an 8 week post treatment
period.
Cattle Trials
[0134] Two trials were compared, conducted using test composition in cattle over 4 geographic
sites over 2 seasons. The sites differed between trials so only trial number was used
as a variable in the analysis. The ANOVA results are shown in Table 7.

[0135] Table 7 shows that there were significant differences between EP treated and Control
faeces over the 8 week study period and this varied over time. There was a significant
interaction between the individual trials over time.
[0136] Table 8 shows the mean numbers of cattle parasite larvae in the pasture samples over
the 8-week trial period for the 2 trials as well as the corresponding overall values.
The overall mean larval count for the Control samples was 16,038 larvae compared to
3,059 larvae for the test composition treated samples (P= 0.006).

[0137] Figures 6 - 7 shows that larvae from the Control faeces increased rapidly by 4 weeks
and thereafter remained at a high level through to 8 weeks post treatment. In comparison,
larvae found emerging from test composition treated faeces rose only minimally over
the entire observation period. Variability was marked across the trials but a significant
difference was observed at 8 weeks post treatment. Overall, the total number of larvae
emerging from EP-treated faeces over the 8 week observation period was significantly
reduced compared to the Control faeces (Tables 7 & 8).
[0138] This response varied between the two trials (Figures 6 - 7), with larval values reaching
a maximum at 4 weeks in trial # 2528, whereas in trial # 2634 there was a slower build
up to a peak at 8 weeks. This may have been due to differing climatic and local conditions
at each site.
Conclusions from cattle experiments
[0139] Overall, treatment of cattle with EP significantly (P=0.006) reduced the detection
of cattle parasite larvae on pasture surrounding faeces over an 8 week post treatment
period.
Goat Trials
[0140] Three trials were compared, conducted using EP in goats at 6 geographic sites over
3 seasons. Since goats have a relatively low faecal output, for two of the goat trials
(#2635 and #2719) the faecal samples were collected from pairs of goats. The sites
differed between trials so only trial number was used as a variable in the analysis.
The ANOVA results are shown in Table 9

[0141] Table 9 shows that the effect of treatment with EP was statistically-significant
over the 8 week observation period. There was also a significant interaction between
time and trial.
[0142] Table 10 shows the mean numbers of goat parasite larvae in the pasture samples over
the 8-week trial period for the 3 trials as well as the corresponding overall values.
The overall mean larval count for the Control faeces was 12,866 larvae compared with
only 1,834 larvae after test composition treatment (P=0.01).

[0143] Figures 8-10 shows that the larval emergence seen differed in pattern to the horse
and cattle studies in that for goat faeces, the parasitic larvae emergence was greater
in the first 2 weeks post treatment and then declined. Variability was marked by week
but overall, the total number of larvae emerging from composition treated faeces over
the 8 week observation period was significantly reduced compared to the Control faeces
(Tables 5 & 6).
[0144] This response varied across the three trials, with more larvae found at 2 weeks post
treatment in #2719, 4 weeks in #2527 and 6 weeks in #2635.
Conclusions
[0145] Overall, administration of the EP to goats significantly (p=0.01) reduced the detection
of goat parasite larvae on pasture surrounding the faeces over an 8 week posttreatment
period.
Overall Conclusions
[0146] Treatment of horses, cattle and goats with the EP lead to significant (p≤0.01) reductions
in parasite larvae of all three animal species on pasture surrounding their faeces
over an 8 week post-treatment period.
EXAMPLE 9
[0147] By way of non-limiting example only, the following table provides a summary of issues
encountered in establishing safety and obtaining regulatory approval for a commercial
biological control product of the invention.
Table 11 Summary of Safety Issues
| Safety |
Issue |
How addressed |
Time frame |
| Infectivity/ pathogenicity |
1. Needed to prove that D. flagrans strain IAH 1297 was not infective / pathogenic. Lungs were most appropriate site for this
investigation because they provide an aerobic environment. However, even individual
spores were too big to enter the lungs by inhalation (20 microns) as they become trapped
in nasal cavity and airways. |
Method developed for direct instillation of powdered spore concentrate into trachea.
Trial conducted to determine maximum tolerable dose. |
Items 1-10 relate to the program of toxicology testing conducted in laboratory animals. |
| Initial enquiries with a toxicology lab (RDDT Laboratories, Melbourne) began in May
2010. This lead to a series of rolling consultations with regulatory agencies, regulatory
consultants and toxicologists to decide which tests were required, test protocol details
and choice of test item. Testing began in December 2014 and last report was received
in Jan 2016. |
| Total time required 5 years 8 months. |
| |
2. Regulators required high dose (suggested 108 spores). |
Developed a process for purifying the TGAI to maximise the spore dose that could be
administered |
| |
3. Instillation of particulate matter induced physiological |
Trial included control group with inactivated spores (gamma irradiation) |
| |
response that may be mistaken as adverse effect attributable to D. flagrans pathogenicity / toxicity (e.g. non specific pneumonia). |
to demonstrate that symptoms were due to inhalation of particulate matter, not due
to pathogenicity / toxicity of the spores |
|
| |
4. Regulators required enumeration of spores in lung |
Method developed and validated to enumerate spores in rat lung |
| |
5. Regulators required demonstration of clearance of spores from the body, but clearance
mechanisms in the lung aren't adept at clearance of 20 micron spores because particles
of this size do not normally reach the lungs |
Trial period was extended until clearance was finally achieved (6 weeks) |
| Dustiness |
6. Needed to quantify the risk of inhalation of particulate matter by workers and
animals |
Dustiness test conducted showing feed supplement (MP) is "practically dust free" |
| Particle size |
7. Needed to prove that finer particles are too large to be inhaled by workers and
animals |
Dry sieve analysis showed feed supplement (MP) has no particles less than 50 microns |
| Acute oral toxicity |
8. Needed to show that D. flagrans strain IAH 1297 isn't toxic by oral administration. Regulators required as high dose
as possible |
Developed a process for purifying the (TGAI) to maximise the spore dose that could
be administered at upper dose level used in such trials (5g/kg BW) |
|
| Irritancy - Eye |
9. Needed to assess irritancy but EP and MP contain a known ocular irritant (calcium
carbonate) |
Eye irritancy studies (in vitro and in-vivo) conducted with EP |
|
| Dermal irritancy and toxicity |
10. Calcium carbonate in EP and MP may also be a skin irritant |
Dermal irritancy and toxicity studies conducted with EP |
| Chronic oral toxicity |
11. Data from long term mammalian studies required |
Addressed via long-term high-dose safety studies in target animals |
Sheep study: Planning commenced July 2009, and study report received Feb. 2010. |
| |
|
Total time required 7 months. |
| Target animal safety |
12. Need to demonstrate long-term safety under field conditions |
Long-term (6-8 weeks) high-dose (5-10X) safety studies conducted in sheep, cattle
and goats |
Cattle and horse studies: Planning commenced March 2013, and study reports received
Dec 2013. |
| Total time required 9 months. |
| |
13. Large quantity of spores required (approx. 500kg feed supplement (EP) per trial
with 10X spore inclusion rate, equivalent to 5 tonnes normal product) |
Production of TGAI was scaled up. |
Commenced January 2013, completed June 2013 |
| |
|
Total time required 6 months |
| Residues |
14. Secondary metabolites (flagranones A, B and C) of D. flagrans were known, but no information was available about metabolite production by strain
IAH 1297. |
Conducted fermentation studies; showed that flagranone A is the single major metabolite
of D. flagrans strain IAH 1297, that flagranones B and C are not produced and that other structurally-related
materials are less than 5% of flagranone A |
Project planning started October 2014, report received December 2015. |
| |
Total time required 14 months |
| |
15. No published toxicology data was available for flagranones |
Toxicological properties investigated by means of in-silico desktop studies using
QSAR technology |
Planning commenced April 2012, report received June 2016. |
| |
Total time required 4 years. |
| |
16. No analytical reference material available for flagranone A |
Purified flagranone A isolated and characterised by a specialist natural products
chemist. |
Phase 1: Project planning started April 2008, report received Oct 2008. |
| |
Total time required 6 months |
| |
Phase 2: Project planning started October 2014 report received December 2015. |
| |
Total time required 14 months |
| |
17. Flagranone A pure reference material is unstable, but degraded material appears
chromatographically pure, which results in inflated assay results |
Stability study conducted with flagranone A. Pure material can be stabilised by storage
in sealed ampoules in the dark at -80C, but not -20C |
Project planning started October 2014, report received December 2015. |
| |
Total time required 14 months |
| |
18. No analytical methods existed for assaying flagranone A in TGAI, MP and EP. |
Methods developed and validated for assay of flagranone A in TGAI, MP and EP |
Phase 1: Planning started April 2013, reports received March 2014. |
| |
Total time required 11 months |
| |
Phase 2: Planning started July 2015, report received December 2015. |
| |
Total time required 5 months |
| |
|
Analysis of batches of TGAI showed that worst case daily intake by recipient animals
were below the levels that trigger the requirement for feeding studies to assess residue
levels in food products derived from recipient animals |
Total time required 1 month, |
| |
19. No data was available on worker exposure to flagranone A |
Using analytical data from TGAI and suitable exposure models it could be shown that
worst-case exposure levels of manufacturing workers and farm workers handling feed
supplement (EP) were below levels of concern |
Total time required 1 month, |
| |
20. No data was available on intake levels for consumers eating products derived from
feed supplement (EP)-treated animals |
Using analytical data from TGAI it was shown that worst-case intake would be below
levels of concern. |
Total time required 1 month, |
EXAMPLE 10
Toxicology studies
[0148] By way of non-limiting example only, toxicology testing was conducted with the composition
of the invention. The composition is also a biological control product. The composition
of the invention was prepared for example, according to Example 3 and further formulated
to produce EP and/or MP according to Example 4.
Selection of test items
[0149] The test items for these studies were selected according to the objective and context
of the test. The acute oral toxicity, and the acute pulmonary toxicity and infectivity
studies were conducted with purified TGAI i.e. a concentrated preparation of the spores
of D.
flagrans strain IAH 1297 (the active constituent) to ensure that the highest possible dose
of spores was administered in each case. Other studies, such as the ocular and dermal
irritation tests, were conducted using EP, which was considered to be more relevant
to users of the product.
Data Summary and Overview
[0150] The suite of international standard Good Laboratory Practice toxicology studies that
was carried out is summarised below; none of these studies indicated any cause for
concern.
[0151] The acute oral toxicity study showed that the D.
flagrans spores in the purified TGAI are not toxic. A dose of 5,000 mg/kg B.W. in rats did
not cause any clinical signs and accordingly, the oral LD50 dose was greater than
5,000 mg/kg bodyweight.
[0152] In the acute pulmonary toxicity and infectivity study the spores of the purified
TGAI were instilled directly into the lungs because the spore diameter of between
20-24 microns meant they were too large to be inhaled into the lungs. Instillation
of spores into the lungs did not induce signs of toxicity or infectivity, apart from
laboured breathing which was resolved in 3-4 days (the same result was obtained with
attenuated product). The spores were eventually cleared from the lungs.
[0153] An acute dermal toxicity study conducted by application of EP to a dermal patch with
the limit dose of 5,000 mg/kg bodyweight also indicated no toxicological effects.
[0154] An acute skin irritation test concluded that EP is classified as non-irritant when
applied to rabbit skin. Testing of the feed supplement EP according the CIPAC test
method TM171 for dustiness showed the product is defined as non-dusty, and this will
contribute to the safety of the product.
[0155] An acute eye irritation study using EP concluded that conjunctival irritant effects
occurred after 1 hour, but these effects were fully reversible within 72 hours. No
corneal effects were observed. This information was supported by an in vitro eye irritation
study with isolated chicken eyes where the product was not classified as either a
severe irritant or non-irritant.
[0156] Long-term high-dose safety studies at 5x times the proposed dose in sheep and 10x
times in cattle and horses have confirmed the safety of TGAI. Studies by other researchers
support this finding.
[0157] The data provided supports regulatory approval for the composition or biological
control product of the invention.
[0158] A number of relevant physical characteristics of MP were also determined, notably
the dustiness according to the CIPAC test method TM171, and a sieve analysis according
to CIPAC TM170. Using CIPAC criteria for dustiness, MP was found to be "nearly dust-free";
and the dry sieve analysis showed no material retained on, or passing through a 50
micron mesh. Also, a determination of the
D.
flagrans spore size is provided as there is a relationship between the aerodynamic size of
any dust particle and its ability to be inhaled or respired. All of these test results
provide evidence of the low-risk nature of the products.
[0159] Attention has also been paid to the secondary metabolites of
D.
flagrans strain IAH 1297. This strain produces a single major metabolite, flagranone A, and
analysis has shown that this material is present at levels that are too low to be
of toxicological concern.
[0160] A toxicological overview of
D.
flagrans strain IAH 1297 has been provided by a European Registered Toxicologist. It concludes:
D. flagrans acts in the faeces of the treated animals and is not absorbed into the systemic circulation;
accordingly, no systemic toxicity due to the fungus is expected. This was confirmed
through a series of toxicology studies in laboratory animals and long-term high-dose
safety studies in target animals.
It was concluded that studies in laboratory animals and target species did not indicate
any toxicological effects and that the risks posed by flagranone A (the secondary
metabolite) to the consumer are negligible. Given the nature of the active constituent
no further toxicological testing of the product or these substances is either practicable
or necessary.
Studies on the Active Constituent
Infectivity and Pathogenicity:
[0161] These properties were assessed by means of the GLP acute pulmonary toxicity and infectivity
study referred to below. The lung was considered to be the ideal organ for evaluation
of infectivity and pathogenicity of
D.
flagrans because it has been shown that the spores require oxygen for germination and the
lungs provide an aerobic environment, unlike the alternate test sites (gastrointestinal
tract or peritoneal cavity).
[0162] Choice of test item was dictated by the need to maximise the spore dose that could
be applied. The test item used was the purified TGAI, as it proved impossible to achieve
a higher concentration via small scale laboratory trials. Since the spores have a
diameter of approximately 20 microns it was decided to apply them by direct instillation
into the trachea, bypassing the nose and throat where the spores might otherwise become
trapped.
Acute pulmonary toxicity & Infectivity Study.
[0163] An acute pulmonary toxicity and infectivity study was performed in the rat with animals
treated with a single dose of
D.
flagrans spores IAH1297 in the form of a dry spore powder (purified TGAI), or an equivalent
amount of inactivated spores, using an instillation method.
[0164] Necropsy observations confirmed that spore deposits spread within the lungs following
insufflation, as required for this study. The only significant clinical signs observed
were laboured respiration, noisy respiration, and increased respiration rate in all
animals. These symptoms gradually resolved within the first 3-4 days.
[0165] Based on the results of this study, the test item, when administered to rats as a
single intratracheal dose, does not induce signs of toxicity, infectivity, or pathogenicity.
The results indicate that the maximum dose is determined by the size and physical
surface of the spores, and not by their virulence. This is further confirmed by body
weights increasing as clinical signs were reduced (after about 7 days) in animals
treated with either active or inactivated spores. It is also noted, that after the
42-day period, living spores could not be detected in the lungs of the treated animals.
The slow clearance of spores from the lung was considered to be related to the physical
properties of the test material, particularly the large spore size.
Acute Oral Toxicity.
[0166] An acute oral toxicity study was conducted with
D.
flagrans strain IAH 1297 spores in rats. In this study, 3 rats were given a single oral (gavage)
dose of
D.
flagrans strain IAH 1297 spores (purified TGAI) at the limit dose of 5,000 mg/kg body weight
(BW). The animals were fasted overnight prior to treatment and food was returned 3
hours after dosing.
[0167] Initially, one female was treated at a dose level of 5,000 mg/kg BW. No mortality
was observed so two further rats (confirmatory group) were treated at 5,000 mg/kg
BW. No mortality was observed in the confirmatory group.
[0168] Animals were observed individually after dosing for up to 6 hours post treatment
and once daily for 14 days thereafter. Body weight was measured on Day -1, just before
dosing (Day 0) and weekly thereafter. All animals were examined macroscopically at
the end of the observation period. No specific pathogenicity evaluation was made,
but close examination of animals was made for any adverse effects.
[0169] The study concluded:
- No mortality was observed.
- Treatment with D. flagrans spore (strain IAH 1297) at the dose level of 5,000 mg/kg bodyweight did not cause
any clinical signs.
- There were no treatment related body weight changes. Body weights were within the
range commonly recorded for this strain and age.
- There was no evidence of the macroscopic observations at a dose level of 5,000 mg/kg
BW
[0170] Under the conditions of this study, the acute oral median lethal dose (LD
50) of the test item,
D. flagrans spore strain IAH 1297 (purified TGAI), was greater than 5,000 mg/kg BW (limit dose)
in female CRL:(WI) rats.
[0171] In this study, the quantity of spores fed to the animals is greater than 600-times
the proposed commercial dose for TGAI in MP or EP as follows:
Study dose rate: 5 g of active constituent (the purified TGAI)/kg BW at 3.8 × 106 spores/g (based on the assay result for the specific batch used in the trial) equals
1.9 × 107 spores /kg BW
Proposed dose rate: 6 g MP/100 kg BW or 100g of EP/100kg bodyweight equals 30,000
spores/kg BW
[0172] Separately in 2006, the European Food Safety Authority (EFSA) published their opinion
on the safety of
D.
flagrans as a feed additive for calves. The data considered included an acute oral toxicity
study using 5 five female Sprague-Dawley-derived rats of 11-weeks old given a single
dose of 2,000 mg/kg B.W. Animals were monitored for 14 days, killed by carbon dioxide
inhalation and subject to necroscopy. The study concluded that no toxic effects were
seen after dosing and at post mortem examination of organs examined except the lungs
were of normal macroscopic appearance (lung abnormalities observed were attributed
to the use of carbon dioxide to kill the rats).
[0173] EFSA concluded that the product was of low oral toxicity with an LD
50 greater than 2,000 mg/kg BW or 2 × 10
7 spores/kg BW. EFSA concluded that the fungus has a very low oral toxicity.
D.flagrans Spore Size
[0174] Determination of spore size gave results of 19 microns and 24 microns. This is relevant
as this spore size is too large to be inspired into the lungs which mitigates any
risk due to inhalation of the spores. Also, for this reason the pulmonary and infectivity
study used separated spores as the test item, which was applied by direct intra-tracheal
installation.
Exposure Assessment
[0175] There is no exposure of consumers to
D.
flagrans because the fungus is not absorbed by the recipient animals.
[0176] Worker exposure to
D.
flagrans is minimised by ventilation, dust extractors fitted to manufacturing and packing
equipment in the workplace and use of personal protective equipment.
[0177] A suite of toxicology and long-term safety studies have shown that
D.
flagrans strain IAH 1297 is a low risk material,
Secondary metabolites of D. flagrans
[0178] Flagranones are secondary metabolites produced by
D. flagrans and flagranones A, B and C have been reported. As shown in Example 11, It has been
found that
D.
flagrans strain IAH 1297 (TGAI) does not produce flagranones Band C, and exposure of manufacturing
workers, farmers and consumers to flagranone A from manufacturing and using TAGI,
MP and EP, and from consuming products from treated animals have been determined.
It was found that human exposure falls below the European Threshold of Toxicological
Concern (TTC) value of 1.5 µg /kg BW/ day and animal exposure falls below the level
above which residue studies are considered to be required (4 µg /kg BW/ day).
Studies on the Product
Acute Dermal Toxicity.
[0179] A dermal toxicity test was performed using EP as it was considered that the excipients
might contribute to effects on the skin. In this study rats were treated with a single
semi-occlusive dermal application of EP at the limit dose of 5,000 mg/kg BW. Sufficient
water was used to dampen the test material to ensure good contact with the skin. The
contact period was 24 hours, followed by a 14-day observation. Clinical observations
along with a check of viability and mortality were performed on all animals at 1 hour
and 5 hours after dosing and daily for 14 days thereafter. Body weight was measured
prior to dosing on Day 0, Day 7 and 14. All animals were examined macroscopically
at necropsy at the end of the observation period.
[0180] The results included:
- No mortality observed during the study.
- No adverse clinical signs were observed after treatment with the test item or during
the 14 day observation period and no effects were observed at the site of application.
- There were no treatment related body weight changes.
- Body weights were within the range commonly recorded for this strain and age.
- There was no evidence of adverse effects at the dose level of 5,000 mg/kg BW at necropsy.
[0181] It was concluded that the median lethal dose (LD
50) EP after a single dermal administration was greater than 5,000 mg/kg bodyweight
rats.
[0182] Acute eye irritation tests were performed using EP as it was considered as it represented
the most realistic model of exposure. An
in vitro eye irritation test was conducted using isolated chicken eyes with EP as the test
item. The procedure involved applying the test item in a single dose onto the cornea
of isolated eyes that have been obtained from slaughter animals.
[0183] After the zero reference measurements, the eye was held in horizontal position and
test item was applied onto the centre of the cornea such that the entire surface of
the cornea was covered. After 10 seconds, the surface was rinsed with saline. The
positive control eyes were treated with 30 mg Imidazole. The negative control eye
was treated with 30 µL of physiological saline. In the study, three test item treated
eyes, three positive control treated eyes and one negative control treated eye were
examined.
[0184] No significant corneal swelling was observed during the four hour observation period.
Corneal opacity change (severity 0.5 or 1) and fluorescein retention change (severity
0.5 or 1) was noted on all test item treated eyes; furthermore, particles of test
item were stuck to the cornea and could not be washed off during the study. Overall,
the effects were clearly greater than a negative effect, but not sufficient to classify
them as severe. The particles stuck to the cornea could potentially result in mechanical
corneal damage in vivo.
[0185] The
in vitro eye irritation indicated that EP is not classified as either a severe irritant or
non-irritant. It was concluded further information would be required for classification.
In-vivo eye irritation
[0186] Three young adult male New Zealand White rabbits were used in this trial and the
test item (EP) was administered as a single dose into the conjunctival sac of the
left eye with the untreated right eye serving as control. Irritation effects were
scored at different times up to 72 hours as shown below after test item installation
into the eye.
[0187] Observations with fluorescein staining were made approximately 24 hours before treatment
and then 24, 48 and 72 hours after the treatment in all animals. Rabbits were treated
with analgesic and anaesthetic as per the regulatory guideline. Results obtained from
these three animals were used to classify the test item for irritation potential.
No specific pathogenicity evaluation was made, but close examination of animals was
made for any adverse effects. Irritation to the conjunctivae, iris and cornea are
assigned a numerical score.
[0188] The following data was obtained:
First animal (No: 1393) clinical observation:
[0189] At 1 hour after application, conjunctival redness (score 2), chemosis (score 1) and
discharge (score 2) were noted in the rabbit. Test item remained in the eye sac at
the one hour observation time point in the rabbit. At 24 hours after application,
conjunctival redness (score 2), chemosis (score 1) and discharge (score 1) were noted
in the rabbit.
[0190] At 48 hours after application, conjunctival redness (score 1) was noted in the rabbit.
At 72 hours after application, no clinical signs and no conjunctival or corneal effects
were observed.
Second animal (No: 1398) clinical observation:
[0191] At 1 hour after application, conjunctival redness (score 2), chemosis (score 1) and
discharge (score 2) were noted in the rabbit. Test item remained in the eye sac at
the one hour observation time point in the rabbit. At 24 hours after application,
conjunctival redness (score 2) and discharge (score 1) were noted in the rabbit.
[0192] At 48 hours after application, conjunctival redness (score 1) was noted in the rabbit.
At 72 hours after application, no clinical signs and no conjunctival or corneal effects
were observed.
Third animal (No: 1390) clinical observation:
[0193] At 1 hour after application, conjunctival redness (score 2), chemosis (score 1) and
discharge (score 2) were noted in the rabbit. Test item remained in the eye sac at
the one hour observation time point in the rabbit. At 24 hours after application,
conjunctival redness (score 2) and discharge (score 1) were noted in the rabbit.
[0194] At 48 hours after application, conjunctival redness (score 1) was noted in the rabbit.
At 72 hours after application, no clinical signs and no conjunctival or corneal effects
were observed.
[0195] Fluorescein staining was negative in all animals during the observation period. As
no clinical signs were observed, the experiment was terminated after 72 hours' observation.
[0196] During the study, the control eye of each animal was symptom-free. The general state
and behaviour of animals were normal throughout the experimental period. The bodyweights
of all rabbits were considered to be within the normal range of variability. However,
a slight body weight loss was noted in one animal (No.1393) during the observation
period.
[0197] It was concluded that EP, applied to the rabbits' eye, caused conjunctival irritant
effects at one hour after the treatment which were fully reversible within 72 hours.
There were no corneal effects observed in the study.
Acute Skin Irritation
[0198] An acute skin irritation study was undertaken using EP. Three (3) young adult New
Zealand White rabbits were treated by topical, semi-occlusive application of test
composition item (EP) to their intact shaved flanks. The test item was moistened with
water to ensure good skin contact. The duration of treatment was 4 hours.
[0199] The scoring of skin reactions was performed at 1, 24, 48 and 72 hours after removal
of the dressing. The primary irritation index (P.I.I.) was calculated by totalling
the mean cumulative scores at 24, 48 and 72 hours and then dividing by the number
of data points. No specific pathogenicity evaluation was made, but close examination
of animals was made for any adverse effects.
[0200] In this study, the following results were obtained:
- The primary irritation index was 0.00.
- No local dermal signs were observed in the treated animals throughout the study.
- No clinical signs of systemic toxicity were observed in the animals during the study
and no mortality occurred. As no clinical signs were observed at 72 hours after patch
removal, the study was terminated after 72 hours observation.
- The body weights of all rabbits were considered to be within the normal range of variability.
[0201] According to the Draize classification criteria, EP is considered to be "not irritant"
to rabbit skin (P.I.I. = 0.00).
[0202] A decrease of body weights was observed, but animals returned to their original body
weights after approximately 7 days. After this period there were no treatment-related
effects on body weight or body weight gain and body weights were within the range
commonly observed for this strain and age of rat.
Other Studies
Dustiness study
[0203] A GLP dustiness study with MP according to the CIPAC test method MT171 showed that
it was "nearly dust-free".
Sieve Analysis
[0204] In addition, a GLP dry sieve analysis study with MP was conducted according to CIPAC
TM170. The dry sieve analysis showed no material retained on, or passing through a
50 micron mesh.
[0205] Also, above the spore diameter for D.
flagrans strain IAH 1297 was shown to be approximately 20 microns.
[0206] These results are significant as these characteristics will reduce the likelihood
of exposure to the eye and skin and by inhalation.
Long-term high-dose safety studies with TGAI in EP
[0207] Long term, high-dose safety studies for cattle, sheep and horses are summarised below.
Long term safety study in cattle (10x dose)
[0208] A GCP study was conducted in cattle to confirm the safety of TGAI when administered
to cattle at an elevated dose rate (ten times the normal dose) for eight weeks.
[0209] Twenty Angus cattle (female and male castrates, aged less than 12 months) were recruited
from the same pool of animals and acclimatised to consumption of the placebo product
(Livamol
®), 125 g/100 kg bodyweight/day). Following this, they were drafted into two groups
of 10 animals based on sex and bodyweight. For the following 56 days Group 1 (Control
Group) continued to receive the placebo product, while Group 2 (Test Group) were given
125 g/100 kg bodyweight/day of EP containing 10 times the usual amount of TGAI (equivalent
to minimum 3 × 10
5 spores/kg bodyweight/day). This dose is ten times that used for control of intestinal
nematodes (3 × 10
4 spores/kg bodyweight/day) in cattle.
[0210] Safety of TGAI was confirmed via repeated clinical examinations by veterinarians,
bodyweight change over time and serum biochemistry and haematology, in comparison
with untreated cattle. Detailed clinical examinations were conducted on Days -10,
3, 7, 14, 28 and 56, bodyweights were measured on Days -10, 7, 14, 28 and 56, blood
samples were taken for serum biochemistry and haematology on days -10, 14 and 56.
[0211] No evidence of acute or chronic toxicity or infection (apart from theileriosis in
two cattle in the control group) was observed during the course of the study. Overall,
no adverse clinical, bodyweight gain, biochemical or haematological signs were observed
during the study that could be associated with feeding of TGAI over an extended (56
day) period, the TGAI dose comprising 10x the number of
D.
flagrans spores required for control of intestinal nematodes in cattle.
Long term safety study in horses (10x dose)
[0212] A GCP study was conducted in horses to confirm the safety of TGAI when administered
to horses at an elevated dose rate (ten times the normal dose) for eight weeks.
[0213] Twenty horses (Warmblood, Thoroughbred and Australian Stock Horse; female, male castrate
and male, aged 3 to 12 years) were recruited from the same pool of animals and acclimatised
to consumption of the placebo product (Livamol
®, 125g/100 kg bodyweight/day). Following this, they were allocated to two groups of
10 animals based on bodyweight. For the following 56 days Group 1 (Control Group)
continued to receive the placebo product, while Group 2 (Test Group) were given 125
g/100 kg bodyweight/day of EP containing 10 times the usual dose of TGAI (equivalent
to minimum 3 × 10
5 spores/kg bodyweight/day). This dose is ten times that used for control of intestinal
nematodes (3 × 10
4 spores/kg bodyweight/day) in horses.
[0214] Safety of TGAI was confirmed via repeated clinical examinations by veterinarians,
bodyweight change over time and serum biochemistry and haematology, in comparison
with untreated horses. Detailed clinical examinations were conducted on Days -1, 3,
7, 14, 27 and 56, bodyweights were measured on Days -1, 7, 14, 27 and 56, blood samples
were taken for serum biochemistry and haematology on Days -1, 14 and 56.
[0215] No evidence of acute or chronic toxicity or infection was observed during the course
of the study. Overall, no adverse clinical, biochemical or haematological signs were
observed during the study that could be associated with feeding of TGAI over an extended
(56 day) period, the TGAI dose comprising 10x the number of
D.
flagrans spores required for control of intestinal nematodes.
Long term safety study in sheep (5x dose)
[0216] A GCP study was conducted in sheep to confirm the safety of TGAI when administered
to sheep at an elevated dose rate (five times the normal dose) for six weeks.
[0217] Twenty (20) Merino ewes of approximately 12-13 months of age and weighing between
24.0 and 32.0 kg were acclimatised to consumption of the placebo product (Livamol
®, 100 g/100 kg/day). Following this they were allocated to two groups of 10 animals
based on bodyweight. For the following 43 days Group 5 (Control Group) continued to
receive the placebo product while Group 6 (Test Group) were given 100 g/head/day of
EP containing 5 times the usual amount of TGAI (equivalent to minimum 1.5 × 10
5 chlamydospores/kg bodyweight/day). This dose was five times the proposed usage rate
for control of intestinal nematodes (3 × 10
4 spores/ kg bodyweight/day) in sheep.
[0218] Safety of TGAI was confirmed via repeated clinical examinations by veterinarians,
bodyweight change over time and serum biochemistry and haematology, in comparison
with placebo treated sheep. Detailed clinical examinations were conducted, bodyweights
were measured and, blood samples were taken for serum biochemistry and haematology
on Days -1, 7, 15, 29 and 43.
[0219] No evidence of acute or chronic toxicity or infection was observed during the course
of the study. Overall, no adverse clinical, biochemical or haematological signs were
observed during the study that could be associated with feeding of EP over an extended
(43 day) period, the EP dose comprising 5x the number of
D.
flagrans spores required for control of intestinal nematodes.
Sub-chronic repeated dose oral toxicity studies
[0220] An Indian isolate of
D.
flagrans was screened for possible short-term toxicological effects using a mouse model. Following
the feeding of 1 × 10
6 spores per head daily for one month, no mortality of mice and no significant differences
in body weights between fungus fed and control mice could be recorded. Fungus fed
and unfed mice had similar general appearance, colour and reflex movements. No evidence
of internal mycosis was observed in fungus fed and control mice and on tissue sections
of liver, lungs and kidney.
Determination of No Observed Adverse Effect Levels (NOAEL)
[0221] No adverse effects were noted in any acute toxicity study in laboratory animals nor
in any medium term or chronic feeding study at intended dose levels of TGAI or at
10 fold the intended dose level of TGAI in cattle and horses and 5 times intended
dose in sheep. These studies are supported by numerous studies in the public domain
in cattle, sheep, goats and horses.
[0222] On this basis it was concluded that the NOAEL was greater than 60 g feed supplement
(MP) per 100 kg BW/day corresponding to more than 3 × 10
5 spores/kg BW/day of D. flagrans strain IAH 1297.
Reproduction Studies (including prenatal developmental toxicity).
[0223] Since D.
flagrans is not resorbed from the gastrointestinal tract of treated organisms or humans and
in addition the spores do not germinate at 37 °C or in the absence of oxygen, there
is no indication for reproductive toxicity.
EXAMPLE 11
[0224] By way of non-limiting example only, residue testing was conducted with the composition
of the invention. The composition of the invention was prepared for example, according
to Example 3 and further formulated to produce EP and/or MP according to Example 4.
Residues Data Summary
[0225] As a natural microorganism,
D. flagrans IAH 1297 is orally administered e.g., as spores in the composition of the invention
which are not absorbed and, thus, cannot form residues in edible tissues.
[0226] Anderson
et al. (1999) reported on the identification of secondary microbial products, flagranones
A, B and C which are produced by
D. flagrans. The inventors have conducted further studies on the unique strain of
D.
flagrans IAH 1297. A study of the secondary metabolites of
D.
flagrans strain IAH 1297 found that it produced a single major metabolite identified as flagranone
A. Other minor metabolites were found to be present at levels less than 5% of flagranone
A and it is noteworthy flagranones B and C were not detectable. This study examined
the chemistry of flagranone A and reported that the speed at which flagranone A is
degraded under laboratory conditions means it is improbable the metabolite would have
more than a brief transitory existence in an
in vivo or environmental situation.
[0227] Due to a lack of available literature on toxicological properties of flagranones,
an
in-silico toxicological analysis using Derek Nexus and Leadscope was conducted on flagranones
A, B and C across a range of endpoints and in a number of mammalian and bacterial
species. This was required to characterise the potential toxicity of flagranones A,
B and C and to assess the possibility that they may be present in food products so
that any risk to consumers may be assessed. Flagranones B and C are not produced by
D. flagrans strain IAH 1297 but were included for completeness. Also, a full Derek Nexus analysis
was performed for all three flagranones. The genetic toxicity and rodent carcinogenicity
suites of Leadscope were used for all three flagranones; in addition, flagranone A
was analysed using the reproductive toxicity suite.
[0228] Flagranone A was predicted to be irritant and potentially sensitising but was not
predicted to be mutagenic, carcinogenic or toxic to reproduction.
There were no structural alerts for genotoxicity.
[0229] Following
in silico analysis using Derek Nexus and Leadscope software(s), it was concluded that the potential
presence of flagranones in MP or EP does not pose any undue toxicological hazard or
risk to consumers. This is based on the following:
- That flagranones B and C, although predicted to be genotoxic and/or mutagenic, are
not present in TGAI, MP or EP.
- The conclusion that flagranone A is unlikely to be mutagenic, carcinogenic or toxic
to reproduction.
- That, although predicted to be irritant and potentially sensitising, the concentrations
of flagranone A in tissues or animal products to be consumed are likely to be significantly
below the concentrations at which such effects might be expressed in consumers.
- Review of the structures and calculated physical properties indicates that all three
flagranones would be subject to rapid metabolism and elimination following absorption,
meaning that it is highly unlikely that tissues consumed would have any residue of
these compounds.
Residue data
[0230] A range of commercial batches of
D.
flagrans strain IAH 1297 (TGAI) have been analysed for flagranone A using a validated analytical
method, with results varying between 4.4 mg/kg and 73.6 mg/kg as shown below
Table 12: Flagranone A Results in
D.
flagrans (TGAI) Spore Batches
| Analytical Report No. |
Date |
Batch Number |
Flagranone A Result (mg/kg) |
| 16-0021-6 |
19Jan 2015 |
E03079A |
4.36 |
| 16-0021-1 |
19Jan 2016 |
E03026 |
10.5 (10.1) |
| 16-0021-2 |
19Jan 2015 |
E03039E |
14.4 |
| 16-0021-7 |
19Jan 2015 |
E03079B |
15.6 |
| 16-0021-8 |
19Jan 2015 |
E03105A |
53.2 |
| 16-0021-5 |
19Jan 2015 |
E03064B |
48.1 |
| 16-0021-9 |
19Jan 2015 |
E03105B |
71.6 |
| 16-0021-4 |
19Jan 2015 |
E03064A |
73.9 |
| 16-0021-3 |
19 Jan 2015 |
E03039F |
19.8 |
| Average (mg/kg) |
34.6 |
[0231] Based on the table above a level of 100 µg/g was selected as a conservative maximum
concentration, being approximately three times the average value.
[0232] When the proposed doses of MP and EP are taken into consideration the calculations
of Flagranone A are as shown below:
Residues in Animals
In MP
[0233] Flagranone A content in
D.
flagrans IAH 1297: Maximum level in TGAI: 100 mg/kg or 100 µg/g (conservative value) Dose
rate of MP: 6 g/100 kg BW/day or 0.06 g/ kg BW/day. Therefore, this gives a maximum
daily flagranone A intake by animals: 34.6 µg/g × 0.06 g/kg BW/day = 2.1 µg/kg BW/day.
In EP
[0234] Flagranone A content in
D.
flagrans IAH 1297: 100 mg/kg or 100 µg/g (conservative maximum). Dose rate of EP: 100 g/100
kg BW/day or 1 g/kg BW/day. Therefore, this gives a maximum daily flagranone A intake
by animals: 2.2 µg/g × 1 g/kg BW/day = 2.2 µg/kg BW/day.
[0235] In Regulation (EU) No 283/2013 on data requirements for pesticides in the EU, chapter
6.4., the trigger value for requirement of residue analysis in animal tissues (muscle,
liver and milk) is 4 µg/kg BW/day of the substance in animal feed:
"The objective of feeding studies shall be to determine residues in products of animal
origin which result from residues in feed. Feeding studies shall not be required where
intake is below 0.004 mg/kg bw/day".
[0236] Thus, the exposure level for treated animals is well below the trigger value for
residue analysis laid down in the pesticide Regulation (EU) No 283/2013. Hence, no
residue studies are necessary.
[0237] Flagranone A is described as readily-degradable and the chemical structures indicate
that these are prone to rapid metabolic degradation in mammalian organism, thus there
is no potential for accumulation.
Residue in consumers
[0238] Considering that the above calculated maximum intake of flagranone A for MP and EP
treated animals of 2.2 µg/kg BW/day is distributed to the edible animal tissues (ignoring
metabolic degradation and chemical instability of the flagranone). Considering in
a conservative estimate that 12.74 g meat is consumed per kg BW per day, exposure
would be:
[0239] 2.2 µg/kg animal tissue/day × 0.0127 kg animal tissue/kg BW/day = 0.0279 µg/kg BW/day
[0240] This result is well below the threshold of toxicological concern (TTC), even for
the most critical chemical structures (EFSA, 2012), based on the Cramer Classification
system outlined below.
[0241] The following human exposure threshold values are conservative estimates used in
EFSA's work:
- 0.0025 µg/kg B.W for substances with a structural alert for genotoxicity,
- 0.3 µg/kg B.W for organophosphate and carbamate substances with anticholinesterase
activity,
- 1.5 µg/kg B.W for Cramer Class III and Cramer Class II substances,
- And 30 µg/kg B.W for Cramer Class I substances.
[0242] Taking into consideration that an
in-silico analysis of flagranone A indicated no structural alerts for genotoxicity, the conservative
estimated maximum intake of 0.0279 µg/kg BW/day is more than 53-fold below the relevant
TTC value of 1.5 µg/kg BW/day. It is concluded that exposure to flagranones with EP
or MP is of no toxicological concern for the consumer.
Residue of unknown metabolites other than flagranones
[0243] Other than flagranones, unknown minor metabolites were detected in
D.
flagrans strain IAH 1297 at levels below 5% of the level of flagranones.
18 The following maximum residue levels of these minor metabolites are calculated as
5% (maximum) of flagranone A:
In animal:
- 2.1 × 5% = 0.105 µg/kg BW/day, when MP is fed
- 2.2 × 5% = 0.11 µg/kg BW/day, when EP is fed
[0244] Both results are much lower than the 4 µg/kg BW/day trigger level, hence, no residue
studies are necessary.
[0245] In consumers:
- 0.0279 × 5% = 0.001395 µg/kg BW/day
This is below the TTC value of 0.0025 µg /kg BW/ day even for substances with a structural
alert for genotoxicity.
[0246] Consumer exposure to flagranone A via consumption of products from treated animals
is less than 0.0279 µg /kg BW/day which is more than 53 fold below the relevant TTC
value of 1.5 µg /kg BW/ day. As the exposures are 53 to 625 fold below the TTC, flagranone
A can be presumed to present no appreciable human health risk.
Residue exposure for manufacturing and farm workers
[0247] A summary is provided below:
Farm worker/user exposure to the secondary metabolite flagranone A was determined
to be less than 0.0135 µg/kg BW/day which is more than 111 fold below the relevant
TTC value of 1.5 µg /kg BW/day.
[0248] Manufacturing worker exposure to flagranone A was determined to be less than 0.0024
µg/ kg BW/day which is 625 fold below the relevant TTC value of 1.5 µg /kg BW/ day.
Analytical Methodology
Fungal Concentrates (TGAI)
[0249] The method development, validations and results for flagranone A in TGAI is summarised
below.
[0250] The method has been developed and validated in accordance with SANCO/3030/99 rev.4
11/07/00, APVMA Guidelines for the Validation of Analytical Methods for Active Constituent
and U.S. EPA Test Guidelines, OPPTS 830.1800 in a GLP study.
[0251] Scope: the method is applicable to the determination of flagranone A in TGAI. The
method was validated over the linear range 0 -1000 mg/kg flagranone A in TGAI with
recovery levels over the range of 10 - 600 mg/kg.
[0252] Reference standard of flagranone A had a purity of 99.5%. The reference material
was stored in a freezer on dry ice until prepared as a solution.
[0253] Method of Analysis: Residues of flagranone A were extracted from 10 g of blended
and homogeneous TGAI (fermented grain) samples. Samples were centrifuged and an aliquot
of the supernatant is taken, diluted, filtered and analysed for flagranone A using
high performance liquid chromatography (HPLC) with UV detection.
[0254] Selectivity/Interference: The amount of interference (if any) was evaluated by comparing
the results from the analysis of control samples and reagent blanks with an LOQ standard.
Chromatograms were considered acceptable if components present in control extracts
and reagent blanks, which could potentially interfere with the analysis, were not
present at levels of greater than 3% of the limit of quantitation. No interfering
substances were observed greater than 3% of the Limit of Quantitation (LOQ).
[0255] Linearity: In order to establish the linearity of response of the analytical chromatography
system to the test substance, ten flagranone A standards of increasing concentration
were prepared. The concentration range spanned at least 80-120% of the expected concentrations
in the recovery samples. The standard curve was constructed with the following concentrations
of flagranone A: 0.005, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 50 and 100 mg/L. The system
linearity was accepted where a statistical analysis showed significant linearity with
r
2 > 0.99. Each calibration curve had a correlation coefficient (r
2) of ≥ 0.99 thereby showing sufficient linearity.
[0256] Precision and Accuracy (Recovery): The 10, 50 and 150 mg/kg recovery samples were
prepared by adding aliquots of the stock solution of flagranone A onto 10 g portions
of each control grain. The 600 mg/kg recovery samples were prepared by weighing approximately
6 mg of flagranone A onto 10 g portions of each control grain. The 10, 50, 150 and
600 mg/kg concentration levels when converted to % w/w are 0.001, 0.005, 0.015 and
0.06%, respectively. Therefore, the acceptable mean recovery range for the data in
this method validation study is 75-125%.
[0257] An aliquot of the extract was taken, filtered into LC vials and analysed according
to the method. The recovery samples were fortified at 10, 50, 150 and 600 mg/kg in
fungal concentrates. Results were in the range 98-105%.
[0258] The precision of the method was demonstrated by analysing five replicates at 10,
50 and 150 mg/kg validation levels in fungal concentrates. The relative standard deviations
(RSD) were determined at the 10, 50 and 150 mg/kg fortification levels. Precision
was considered acceptable if the RSD was ≤ 20%. The precision of the recovery data
for this study met the acceptance criteria.
[0259] Limit of Quantitation (LOQ): The LOQ is determined by analysing the estimated LOQ
concentration a minimum of 6 times. The average response (X) and standard deviation
(SD) is calculated. The standard deviation should be < 20%. The LOQ is calculated
as: X + (10 × SD). The estimated LOQ is 1.1 mg/L which is equivalent to 11 mg/kg in
sample.
[0260] Limit of Detection (LOD): The LOD is determined by analysing the lowest calibration
standard which produces a peak (minimum of 6 replicates). The average response (X)
and standard deviation (SD) is calculated. The LOD is calculated as: X + (3 × SD).
The estimated LOD is 0.005 mg/L which is equivalent to 0.04 mg/kg in sample.
[0261] System Precision: The 1 mg/L flagranone A standard solution was injected ten times
to assess the system precision. The system precision was considered acceptable if
the RSD ≤ 1% for retention time and ≤ 20% for peak area. The RSD for the retention
time was found to be 0.1% and the RSD for the peak area was found to be 6.9%.
[0262] Method Precision: The method precision was evaluated by analysing at least five freshly
prepared recoveries fortified at 10 mg/kg over two days with freshly prepared standards
for each analysis. The within-run relative standard deviation and between- run relative
standard deviation was considered acceptable if ≤ 20% for the 10 mg/kg fortification
level. The relative standard deviation for the within-run was found to be 2.7% on
day 1 and 0.8% on day 2 and the between-run relative standard deviation was found
to be 1.9%.
[0263] Solution Stability: Aliquots of the final extracts of untreated control grains were
fortified with flagranone A at concentrations of 1 mg/L and 15 mg/L (equivalent to
the 10 mg/kg and 150 mg/kg recovery levels in the final extract). Aliquots were also
fortified with flagranone A at concentrations of 1 mg/L and 15 mg/L. The concentration
of the analyte was quantified against freshly prepared neat standards after 7 days
storage at approximately -20 °C in the dark. Freshly prepared final extracts were
fortified at equivalent concentrations to compare against the 7 day stability samples.
Results were in the range 101-107%.
[0264] Method Robustness: The method ruggedness was tested by re-analysing a previously
prepared set of standards and recoveries and varying the make-up of the mobile phase.
The remainder of the HPLC-UV conditions remained unchanged. Adjusting the mobile phase
composition had no major impact on the response to flagranone A
[0265] It was concluded that this method is fit for the purpose of analyzing flagranone
A in TGAI. The parameters validated in this study meet the acceptance criteria according
to SANCO/3030/99 rev.4 11/07/00 APVMA Guidelines for the Validation of Analytical
Methods for Active Constituent and U.S. EPA Test Guidelines, OPPTS 830.1800.
MP and EP.
[0266] The method development, validations and results for flagranone A in MP and EP are
summarised below.
[0267] The method has been developed and validated in accordance with SANCO/3030/99 rev.4
11/07/00, APVMA Guidelines for the Validation of Analytical Methods for Active Constituent
and U.S. EPA Test Guidelines, OPPTS 830.1800 in a GLP study.
[0268] Scope: the method is applicable to the determination of flagranone A in MP and EP.
The method was validated over the linear range 0 - 100 mg/kg flagranone A in fungal
concentrates with recovery levels over the range of 1 - 60 mg/kg.
[0269] Reference standard of flagranone A had a purity of 99.5%. The reference material
was stored in a freezer on dry ice until prepared as a solution.
[0270] Method of Analysis: Residues of flagranone A were extracted from 10 g of homogeneous
samples by tissumising and shaking. Samples were centrifuged and an aliquot of the
supernatant is taken and diluted, filtered and analysed for flagranone A.
[0271] Selectivity/Interference: The amount of interference (if any) was evaluated by comparing
the results from the analysis of control samples and reagent blanks with an LOQ standard.
Chromatograms were considered acceptable if components present in control extracts
and reagent blanks, which could potentially interfere with the analysis, were not
present at levels of greater than 3% of the limit of quantitation. Interfering substances
in the control samples were between 0.3-0.4% of the LOQ
[0272] Linearity: In order to establish the linearity of response of the analytical chromatography
system to the test substance, ten flagranone A standards of increasing concentration
were prepared. The concentration range spanned at least 80-120% of the expected concentrations
in the recovery samples. The standard curve was constructed with the following concentrations
of flagranone A: 0.0005, 0.001, 0.0025, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25 and 0.5
mg/L. The system linearity was accepted where a statistical analysis showed significant
linearity with r
2 > 0.99. Each calibration curve had a correlation coefficient (r
2) of ≥ 0.99, thereby showing sufficient linearity
[0273] Precision and Accuracy (Recovery): The recovery samples were prepared by adding aliquots
of a solution prepared from the reference standard of flagranone A onto 10 g portions
of each control animal feed.. An aliquot of the extract was taken, diluted and filtered
into LC vials and analysed according to the method. The recovery samples were fortified
at 1, 5, 20 and 60 mg/kg in MP and EP. The acceptable mean recovery range for the
data in this method validation study was 75-125% and the average value found was 105%.
[0274] The precision of the method was demonstrated by analysing five replicates at each
validation level in MP and EP. The relative standard deviations (RSD) were determined
at each fortification level. Precision was considered acceptable if the RSD was ≤
20%. The precision of the recovery data for this study met the acceptance criteria
[0275] Limit of Quantitation (LOQ): The LOQ is determined by analysing the estimated LOQ
concentration a minimum of 6 times. The average response (X) and standard deviation
(SD) is calculated. The standard deviation should be < 20%. The LOQ is calculated
as: X + (10 × SD). The estimated LOQ was 0.005 mg/L.
[0276] Limit of Detection (LOD): The LOD is determined by analysing the lowest calibration
standard which produces a peak (minimum of 6 replicates). The average response (X)
and standard deviation (SD) is calculated. The LOD is calculated as: X + (3 × SD).
The estimated LOD is 0.0005 mg/L.
[0277] System Precision: The 1 mg/L flagranone A standard was injected ten times to assess
the system precision. The instrument conditions are listed in Section 3.5. The system
precision was considered acceptable if the RSD ≤ 1% for retention time and ≤ 20% for
peak area. The relative standard deviation for the retention time was found to be
0.18% and the relative standard deviation for the peak area was found to be 3.8%.
[0278] Method Precision: The method precision was evaluated by analysing at least five freshly
prepared recoveries fortified at 1 mg/kg over two days with freshly prepared standards
for each analysis. The within-run relative standard deviation and between-run relative
standard deviation was considered acceptable if ≤ 20% for the 1 mg/kg fortification
level. The relative standard deviation for the within-run was found to be 6.4% on
day 1 and 5.4% on day 2 and the between-run relative standard deviation was found
to be 6.0%.
[0279] Solution Stability: Aliquots of the final extracts of untreated animal feeds were
fortified with flagranone A at concentrations of 0.005 mg/L and 0.1 mg/L (equivalent
to the 1 mg/kg and 20 mg/kg recovery levels in the final extract). Aliquots were also
fortified with flagranone A at concentrations of 0.005 mg/L and 0.1 mg/L. The concentration
of the analyte was quantified against freshly prepared neat standards after 7 days
storage at approximately -20 °C in the dark. Freshly prepared final extracts were
fortified at equivalent concentrations to compare against the 7 day stability samples.
Samples were analysed using the conditions listed above. Results were in the range
95-102%.
[0280] Method Robustness: The method ruggedness was tested by re-analysing a previously
prepared set of standards and recoveries and varying the make-up of the mobile phase
'A'. The remainder of the HPLC-UV conditions remained unchanged. Adjusting the mobile
phase composition had no major impact on the response to flagranone A and the method
was considered to be robust.
[0281] It was concluded that this method is fit for the purpose of analysing flagranone
A in MP and EP. The parameters validated in this study meet the acceptance criteria
according to SANCO/3030/99 rev.4 11/07/00APVMA Guidelines for the Validation of Analytical
Methods for Active Constituent and U.S. EPA Test Guidelines, OPPTS 830.1800.