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Trichothecenes
This Page is part of the CU Toxic Plant Pages and was constructed by Yuan-Kuo
Chen.
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 least 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)