Mycotoxins adham

1. Mycotoxins and Poultry Health
by
Adham Omar Sallam MVSc
Department of pharmacology and therapeutics

2. Definition :
Mycotoxins is :
“Mycotoxins are toxic secondary metabolites of certain
species of fungi (molds)”
Thousands of Mycotoxins are present on earth but only 300
have been discovered
Mycotoxins, on ingestion can, cause health hazards in both of
livestock and human beings and hence, there is a greater
economic and public health implication.
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3. 3
1. Aflatoxins
2. Ochratoxins
3. Fusarial toxins (Fumonisins, Zearalenone, Trichothecenes including
Deoxynivalenol and T-2 toxin)
Fungal Mycotoxin
Aspergillus Aflatoxin, Ochratoxin, Sterigmatocystin, Fumitremorgens,
Fumitoxins, Fumigaclavines, Cyclopiazonoic Acid and Gliotoxin
Fusarium Deoxynivalenol, Zearalenone, T-2 Toxin, Fumonisin, Moniliformin,
Nivalenol, Diacetoxyscirpenol, Butenolide, Neosolaniol, Fusaric
Acid, Fusarochromanone, Wortmannin, Fusarin C and
Fusaproliferin
Penicillium Ochratoxin, PR Toxin, Patulin, Penicillic Acid, Citrinin, Penetrem,
Cyclopiazonic acid, Roquefortine, isofumigaclavines A and B and
Mycophenolic acid
The mycotoxins that are of significance in animal feed are:

4. 4
According to the site and time of infestation, the
fungi can be
divided into three groups:
1. Field fungi
• They are generally plant pathogenic fungi; namely Fusarium.
2. Storage fungi
• Mainly, they are Aspergillus and Penicillium.
3. Advanced deterioration fungi
• Normally, they do not infest intact grains but easily attack
damaged grains and requires high moisture content, that include
Aspergillus clavatus, Aspergillus fumigatus
When and why ??

5. 5
Aflatoxins are produced at:
1. Temperature of 25-32 C
2. Moisture of greater than 12-16%
3. Relative humidity of 85%
Why??

6. P.L
‫به‬ ‫املسموح‬ ‫احلد‬ ‫السم‬ ‫نوع‬
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7. 7
Types and their effect

8. effects
Mycotoxins negatively affect:
1. Animal performance
2. Animal health
3. Product quality
Mycotoxins exert their effects through 4 primary
mechanisms:
1. Reduction of feed intake or feed refusal.
2. Alteration in nutrient content of feed in terms of nutrient
absorption and metabolism.
3. Effects on the endocrine and exocrine systems.
4. Suppression of the immune system.

9. Inter-
actions
Known interactions:
Bioavailability (%) of the antibiotic doxycycline
is reduced by Mycotoxin presence (Aflatoxin ).
Effect of Aflatoxin on antibody titres against
infectious bursa disease (IBD) and Newcastle
disease (NC) at 6 weeks.

10. Mode of Action
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11. “
How to treat this problem ?
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Inhibit fungal growth
Detoxification of mycotoxins

12. 12
Fungal Growth Inhibition
The inhibition of fungal growth can be achieved by:
1. Physical treatment
2. Chemical treatment
3. Biological treatment
1- Physical treatment
1) Drying seeds and commodities to the safe moisture level (< 9-11%).
2) Maintenance of the container or store house at low temperature and
humidity.
3) Keep out insects and pests from the storage.
4) Gamma-irradiation of large-scale commodities.
5) Dilution of the contaminated feed with safe feed.

13. 13
2- Chemical treatment
1. Use of fungicides:
– Acetic acid, propionic acid, benzoic acid, citric acid and their
sodium salts, copper sulfate )hydroxyl radicals)
– At rate of 0.2–0.4 % in feed.
2. Use of fumigants
– Ammonia
– At rate of 0.2-0.4%
3. Addition of herbal extracts
– Garlic, onion, clove oil, turmeric powder, thyme
– At rate of 0.25-0.5%

14. 14
3- Biological treatment
a) Enzymes
– Chitin and glucan, as constituents of fungal cell wall, could be
enzymatically hydrolyzed resulting in killing of mycelia or spore of
fungi.
– Anti-fungal enzymes, chitinase and Beta -1,3 glucanase:
• They are found in plant seeds
• They act as defense against pathogenic fungi
– Plant seeds rich in these anti-fungal enzymes likely to resist the
infestation of fungi.
b) Fungal bio-competition
The non-toxigenic biocompetitive Aspergillus strains out-compete the toxigenic
isolates, leading to reduction in colonization of toxigenic fungi in subsequent
years.

15. 15
c) Lactic acid bacterial metabolites
Some bacterial cultures may produce certain metabolites having
antifungal activity as;
1. Cyclic dipeptides
2. Phenylactic acid
3. Caproic acid
4. Reuterin
5. Lactic acid
6. Acetic acid
7. Fungicin
– Streptomyces Spp,. MRI 142 produce Aflastin A, an anti-microbial compound
known to inhibit aflatoxin production by Aspergillus parasiticus.
– Bacillus subtilis produces Iturin, an anti-fungal peptide that inhibits Aspergillus
Parasiticus toxin production.

16. 16
Mycotoxin-detoxifying agents subcategories:
Adsorbing agents (physical) :
One of the strategies for reducing the exposure to mycotoxins is to decrease their
bioavailability by
including various Mycotoxin adsorbing agents in the compound feed, which leads to a
reduction of
Mycotoxin uptake as well as distribution to the blood and target organs.
Adsorbing agents are also called binding agents, adsorbents, binders…
Bio transforming agents (biological) :
Another strategy is the degradation of mycotoxins into non-toxic metabolites by using
bio transforming agents such as bacteria/fungi or enzymes.
Chemical :

17. 17
Mycotoxin-adsorbing agents are large molecular weight compounds that should be able to bind
the mycotoxins in contaminated feed without dissociating in the gastrointestinal tract of the
animal.
In this way the toxin-adsorbing agent complex passes through the animal and is eliminated via
the faces. This prevents or minimizes exposure of animals to mycotoxins.
Mycotoxin-adsorbing agents can be ;
1- Silica-based inorganic compounds (Aluminosilicates)
2- Carbon-based organic polymers (activated charcoals)
3- Yeast cell walls.
4- Micronized fibers.
Adsorbing agents

18. 18
Aluminosilicates
Bentonites
Bentonites are originally created from the weathering of volcanic ash
Bentonites are generally impure clay consisting mostly of montmorillonite. Due to their
montmorillonite content, bentonites swell and form thixotropic gels (Diaz and Smith, 2005).
Montmorillonites
Montmorillonite is a layered silicate which adsorbs organic substances either on its external surfaces or within
its interlaminar spaces (Ramos et al., 1996).
Zeolite :
are crystalline hydrated aluminosilicates of alkali and alkaline-hearth cations characterized by an infinite three-
dimensional structure. Zeolites are a group of silicates consisting of interlocking tetrahedrons of SiO4 and AlO4
- (Kabak et al., 2006; Ramos and Hernandez, 1997).
HSCAS (Hydrated sodium calcium Aluminosilicates)
HSCAS is perhaps the most studied mycotoxin-sequestering agent among the mineral clays (Galvano et al.,
2001);(Diaz and Smith, 2005; Kabak et al., 2006). It is a naturally occurring and heat-processed calcium
montmorillonite that is commonly used as an anticaking additive in animal feed (Wang et al., 2008).

19. 19
Yeast and lactic acid bacterial cell wall structures
can bind with different toxins which would be of
great value in reducing the Mycotoxin.
Yeast as :
• Cell walls derived from the Saccharomyces
cerevisiae yeast are also used as a dietary
mycotoxinadsorbing agent.
• Yeast cell walls consist almost entirely of
proteins ,carbohydrates and layered meshwork
of B-glucans , chitin.
• The carbohydrate fraction is composed
primarily of glucose, mannose, and N-
acetyglucosamine .
Exaple : M.O.S (mannan oligo-saccharides )
Yeast cell walls

20. 20
Yeast compared to clay
clays disadvantages : 1-lead impairment of mineral utilization
2- narrow range of binding efficacy.
3- they may antagonize with other drugs
(HASCS with ionophores)
Beta-glucans (esterified glucomannans), specific sugars
present in the inner cell wall of yeast, can bind aflatoxins.
The levels of inclusion of yeast-based binders are much lower
than clay-based binders i,e About 500 gm of glucomannans from
yeast cell-wall have the
same adsorption capacity as 8 kg of clay.

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Chemical Methods
A variety of chemical agents have been used to degrade
mycotoxins in contaminated feeds, particularly Aflatoxins;
they are;
1. Acids (acidifiers)
2. Bases (ammonia, caustic soda)
3. Oxidants (hydrogen peroxide, ozone, sodium hypochlorite)
4. Reducing agents (Bisulphites)
5. Chlorinated agents
6. Formaldehyde

22. Thanks!
Any questions?
You can find me at:
◇ 01117750519
◇ Adham.sallam@fvtm.bu.edu.eg
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