Mycotoxins in stored feed can be detrimental to animal health with swine and poultry species being especially susceptible. Livestock health issues and poor performance due to the presence of mycotoxins in feed and result is significant economic losses. Mycotoxins are a secondary fungal metabolite. They can be produced in the field of growing crops or in storage post-harvest. The most well-known mycotoxin is aflatoxin. It was the first discovered and has the deepest library of research relative to the other mycotoxins.
Aflatoxin
These toxins are commonly produced in stored grains. Feed mills and grain elevators often test and monitor aflatoxins. They are produced in storage when the temperature is between 77 and 90°F and moisture of the grain is more than 15%.
Aflatoxins cause irreversible liver damage in swine consuming contaminated feeds. Other clinical signs of aflatoxicosis in swine include:
- Decreased growth rates
- Decreased feed efficiency
- Abortions and/or stillborn births
Ochratoxin
Ochratoxins are the most readily produced mycotoxins in stored feed. It is particularly likely to be produced in grains with more than 22% moisture content. In swine, ochratoxins results in kidney damage and impaired renal function. Poultry are more significantly impacted by ochratoxin in their diet. Some clinical signs in poultry include:
- Decreased growth
- Decreased feed efficiency
- Impaired kidney function
- Weak eggshells
- Decreased egg production
- Mortality
Vomitoxin / Deoxynivalenol (DON)
DON does not increase in storage. However, it can end up in feed from production in the field. DON is of concern for both swine and poultry. Swine are most susceptible and here are some clinical signs to be on the lookout for:
- Weight loss
- Decreased feed conversion rates
- Feed refusal
- Vomiting
- Abortion
- Death
Common clinical signs in poultry:
- Decreased egg production
- Thin eggshells
- Abnormal feathering
- Lesions on their beak
- Decreased weight gain
Fumonisin
This is another mycotoxin which does not increase during storage but is produced in the field. This mycotoxin is not particularly detrimental to poultry but can cause a fatal disease in swine. In swine, Fumonisin causes porcine pulmonary edema (PPE). This is a fatal disease and the clinical signs include:
- Respiratory difficulty
- Cyanosis
- Weakness
- Death
- Abortion
Zearalenone (ZEN)
ZEN is another mycotoxin that is produced in the field under specific conditions yet remains present in storage. This mycotoxin interferes with estrogen function and can negatively impact livestock reproductive function. Swine are the most susceptible and common clinical signs are:
- Swollen vulva
- Enlarged mammary glands in young male pigs
- Embryonic death
- Inhibition of fetal development
- Decreased litter size
In addition to these detrimental health and livestock productivity effects, co-occurrence can be an issue. Co-occurrence of mycotoxins in stored feed can results in exacerbated negative effects on animal health. Further, while these mycotoxins are the product of fungus, visual inspection for mold does not determine mycotoxin risk. Mycotoxins can be present without the visual appearance of mold. Especially since they are a secondary metabolite often produced instead of mold replication.
Testing for mycotoxins in stored feeds during an animal health event can help eliminate mycotoxins as the culprit, or identify them as playing a role or even being the cause. Ideally, to evade mycotoxin issues, livestock producers should periodically test stored feeds for mycotoxins to reduce their risk of an animal health event and poor production performance.