Mycotoxins

The term Mycotoxin literally means poison from a fungus. Mycotoxins are highly toxic secondary metabolic products of molds, which impair animal health thereby causing great economic losses of livestock. Mycotoxins can be found in every variety of grain and forage produced for food or feed. They can invade the food supply at any time during production, processing, transport, or in storage. The severity of mycotoxin poisoning varies from feed refusal, vomiting, weight loss, liver and kidney damage, nervous system failure, infertility, to death. Growth of these toxins is often associated with the climate conditions (specific molds grow better in certain conditions), stress, moisture content, and the plants defense mechanisms. There are several factors that influence symptoms such as: type of toxin consumed, intake levels and duration of exposure, animal species, age, sex, and immune status. There are three major genera of fungi that produce mycotoxins: Aspergilius, Fusarium, and Penicilium. Those mycotoxins of most concern, based on their toxicity and occurrence are Aflatoxin, Deoxynivalenol (DON or Vomitoxin), Fumonisin, and Zearalenone. These toxins are also heat stable.

Aflatoxins are produced by both Aspergillus flavus and Aspergillus parasiticus and often cause liver damage and cancer, reduced feed consumption and overall retarded growth and development, decreased milk production and immune suppression. Aspergillus flavus is most often found when certain grains are grown under stressful conditions such as drought. The mold occurs in soil, decaying vegetation, hay, and grains undergoing microbiological deterioration and invades all types of organic substrates whenever and wherever the conditions are favorable for its growth. Favorable conditions include high moisture content and high temperature.

DON also referred to as Vomitoxin, is a naturally occurring mycotoxin produced by several species of Fusarium mold. This mold grows best in cool wet conditions from flowering time on. DON causes vomiting, diarrhea, reduced weight gain, hemorrhaging throughout the digestive tract, infertility and immune suppression. DON is found in all major commodity grain crops in the United States. The two cereal grains most often contaminated with DON are corn and wheat. Although the susceptibility of mycotoxin poisoning differs among species, age, amount of contamination; the industry standard for vomitoxin is no more the 2.0 ppm.

Fumonisin. A mycotoxin often associated with horse deaths, is also produced by Fusarium mold. This toxin is linked to dry hot weather conditions. It is known that in most animals, fumonisin impairs immune function, causes liver and kidney damage, decreases weight gain, and increases mortality rate. Fumonisin also causes leukoencephalomalacia (disease of the central nervous system) in horses and respiratory difficulties in swine. In some animals fumonisin can also cause tumors.

Zearalenone is the primary toxin causing infertility, abortion, and other breeding problems. Swine are the most sensitive to zearalenone, but also dairy cattle. Zearalenone is also produced by Fusarium (cool wet fall conditions favored). Zearalenone production does not seem to occur in significant amounts prior to harvest, but under proper environmental conditions, it is readily produced on corn and small grains in storage.

If you have any questions, please contact:

Linsey Moffit
Agency Quality Assurance Specialist
Eastern Iowa Grain Inspection
1908 S. Stark Street
Davenport, IA 52802
563-322-7149 ext. 206