Mycotoxins are a common problem on farms, and are natural substances produced by moulds. All natural materials and many man-made ones are subject to contamination by moulds and under favourable environmental conditions, when temperature and moisture are conducive, these fungi proliferate and may produce mycotoxins. Over 500 mycotoxins have been identified and this number is steadily increasing.
The impact of these Mycotoxins however can be severe on cattle, pigs, horses, poultry and fish. Moulds grow well on both forage and grains before they are harvested. Mycotoxin inhibitors can control the new fungal growth in crops. But that does not put an end to mould contamination as Storage Mycotoxins are very common in animal feed that is stored after the crop harvest. There are several reasons behind the growth of moulds and related Mycotoxins in a storage environment.
Factors promoting Mycotoxin contamination in storage feed:
- Poor drying conditions and the presence of more than 12% - 15% air moisture.
- Poor sealing and packaging.
- Delayed sealing of foraging and feed grain materials.
- Cold damp temperatures.
- Shady poor storage areas.
- Delayed harvesting of field crops.
- Well aerated atmosphere.
Types of storage moulds and related Mycotoxins:
The two most common storage fungi are Aspergillus and Penicillium. These moulds are tolerant to acids and they frequently occur in silages. There are several species related to these two moulds that produce toxic secondary metabolites known as Mycotoxins that commonly contaminate feed grains and foraging materials.
- The Mycotoxins produced by Aspergillus are - Aflatoxin, Fumitoxins, Ochratoxins, Cyclopiazonoic acid, Gliotoxin, Sterigmatocystin, Fumitremorgens etc. All the toxins can be found in great numbers in contaminated storage grains. Aflatoxin deserves a special mention as it is the most common and it is heavily carcinogenic and can cause many issues within farm animals.
- The Mycotoxins produced by Penicillium are - Ochratoxin, Citrinin, Patulin, PR toxin, Roquefortin C, Penetrem, Mycophenolic acid, etc. Among these Ochratoxin, PR toxin and Patulin are the most common.
Clinical symptoms of storage toxin contamination:
- In the case of Aflatoxin: Reduced milk production, reduced immune responses, reduction in rumen motility, damaged liver (can even lead to hepatic cancer), frequent abortions, etc.
- In the case of Ochratoxins: Easily absorbed by the animal gut this Mycotoxin reduces protein synthesis in the animal’s body, effects the immune system adversely, affects kidneys, reduces normal enzyme actions, reduces cellular respiration, causes abortions and can even lead to cancer.
- In the case of PR toxins: Disturbs rumen homeostasis, retained placental conditions with frequent abortions, reduces normal feed intake, lethargy, irritation and inflammation of gut, etc.
In the case of Patulin: Reduced rumen function, reduced digestive capacity, carcinogenic and death.