There are two main trichothecenes: T-2 toxin and deoxynivalenol (DON). DON is sometimes referred to as vomitoxin because it is known to induce vomiting in swine. The presence of DON in feed is sometimes used as a marker to indicate that the feed was subjected to conditions optimal for mold growth and may be a host for the production of numerous mycotoxins.
Species Producing Trichothecene
Trichothecenes are produced primarily by Fusarium species but may be produced by numerous other genera.
Occurrence of Trichothecene
DON is commonly detected in feeds, while T-2 toxin occurs at a lower incidence. Both generally occur in cooler climates, particularly when warm days alternate with cool nights. Corn is the most common source of trichothecenes, but wheat and other cereal grains may also contain these toxins.
Regulation of Trichothecene
The U.S. Food and Drug Administration (FDA) has set advisory concentrations for DON in feeds depending on the grain used. These are not enforceable “action levels,” however, the FDA considers them an industry guidance. There are no advisory levels or regulations for T-2 toxin, even though it is more toxigenic.
U.S. Food and Drug Administration Advisory Concentrations for Deoxynivalenol (DON) in Dietary Grains and Grain Byproducts
|Grain or Grain Byproducts||Intended Use||DON Levels in Grains or Grain Byproducts and Complete Diet (ppm)|
|Finished wheat products||Human consumption||
|Grain and grain byproducts not to exceed 20% of diet||Swine||
|Grain and grain byproducts not to exceed 50% of diet||Chickens||
|Grain and grain byproducts*||Ruminating beef and feedlot cattle older than 4 months||
|Grain and grain byproducts not to exceed 50% of diet*||Ruminating dairy cattle older than 4 months||
|Distillers grains, brewers grains, gluten feeds, and gluten meals*||Ruminating beef and feedlot cattle older than 4 months, and ruminating dairy cattle older than 4 months||
30 (10 ppm beef/feedlot; 5 ppm dairy)
|Grain and grain byproducts not to exceed 40% of diet||All other animals||
|* 88% dry matter basis|
Source: National Grain and Feed Association
Trichothecenes are immunosuppressive, resulting in a decrease in the number of red and white blood cells. This affects bone marrow and the thymus. The immunosuppressive effects make early lactation dairy cattle more susceptible to toxicosis than other ruminants. DON may result in reduced milk and milk fat yield, lowered weight gain, and reduced intake. T-2 toxin is potent and has been associated with gastroenteritis, intestinal hemorrhages, and death. T-2 toxin may result in feed refusal and gastrointestinal lesions in cows, and calves may experience hindquarter ataxia, listlessness, and anorexia.
Diaz, D. The Mycotoxin Blue Book. 2005. 295–323. Nottingham, UK: Nottingham University Press.
National Grain and Feed Association. 2019. FDA Mycotoxin Regulatory Guidance: A Guide for Grain Elevators, Feed Manufacturers, Grain Processors, and Exporters. Washington, D.C.: National Grain and Feed Association.
Whitlow, L.W. and W.M. Hagler, Jr. 2017. Mold and Mycotoxin Issues in Dairy Cattle: Effects, Prevention and Treatment. eXtension. Accessed 7/20/21.
Publication date: Aug. 23, 2021
Other Publications in Guide to Mycotoxins Commonly Found in Animal Feeds
- Ergot Alkaloids
- PR Toxin
- Ochratoxin A
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