Trichothecenes
Trichothecenes are produced by several common molds including species in the genera Acremonium (Cephalosporium), Cylindrocarpon, Dendrodochium, Myrothecium, Trichoderma, Trichothecium, and most numerously in Fusarium. Trichothecenes are composed of a tetracyclic sesquiterpene skeleton containing a six-membered oxane ring, a stable epoxide group in positions 12 and 13 and a 9,10 olefinic bond. They have been classified into four groups. Fusarium spp. contain several well known trichothecenes including two highly toxic members of group A, diacetoxyscirpenol (DAS) and T-2 toxin, and toxins in group B including deoxynivalenol (DON) and nivalenol. DON is the most common but leat toxic of these. Trichothecenes are strong inhibitors of protein synthesis in mammalian cells. However, DOM received its common name, vomitoxin, from the vomiting that generally accompanies trichothecene poisoning. (D'Mello, et.al., 1991)
DON resulted in feed refusal in swine. In lambs, consumption of a wheat diet containing DON at 15.6 mg/kg of BW for 28 d did not alter feed consumption, weight gain, or feed efficiency. Oral administration of DON showed that it was rapidly passed essentially unchanged (95%) and excreted primarily in urine. Incubation of DON with ruminal microorganisms in vitro for 48 h resulted in partial conversion to deepoxy DON. These results indicate that the impact of DON on ruminants is lower than initially suspected. DON caused no organ damages to animals. Extremely low amounts of DON(<4ng/ml) were transmitted to milk after a single oral dose of 920 mg to a dairy cow. (Diekman and Green, 1992)
The FDA issued an "advisory" to federal and state officials recommending a level of concern for DON of 2 micrograms of DON/ gm for wheat entering the milling process, 1 microgram/ gm in finished wheat products for human consumption, and 4 microgram/ gm for wheat and wheat milling by-products used in animal feed. (Wood, 1992)
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