Stored Grain

Trichothecene Mycotoxins, T-2, HT-2, Diacetoxyscirpenol (DAS)

Barry J. Jacobsen, Robert W. Coppock, and Michelle Mostrom

Fusarium spp.that produce DAS, T-2, nivalenol, and other trichothecenes are listed in Table 1. These fungi commonly attack grains and can grow at temperatures from slightly above freezing to about 86°F (30°C). T-2 and HT-2 toxins are produced over a temperature range of 46° to 77°F (8° to 25°C), with the maximum production at temperatures below 59°F (15°C). This group of mycotoxins, produced by Fusarium poae and F. sporotrichoides, were associated with Alimentary Toxic Aleukia (ATA ), a disease that killed thousands of people in the USSR in 1913, and in the Ukraine from 1940 to 1947.

All domestic animals are susceptible to poisoning by dietary intake of T-2, HT-2, and DAS in the range of a few ppm. In poultry, feed contaminated with 1 to 3.5 ppm of T-2, and 0.7 ppm of HT-2 (a closely related toxicant) may produce lesions at the edges of the beaks, abnormal feathering in chicks, a drastic and sudden drop in egg production, eggs with thin shells, reduced weight gain, hemorrhages in various tissues, increased susceptibility to infections and increased mortality. The same levels fed to turkeys resulted in reduced growth, oral erosions and lowered immunity to infection.

T-2 and DAS in cattle feed results in unthriftiness, decreased feed consumption, slow growth, reduced milk production, diarrhea, abdominal pain, anemia, decreased white blood counts, abortions, bleeding and bruising, decreased immune function and infertility. Field outbreaks of hemorrhagic bowel syndrome and death of some animals is typically associated with the more toxic trichothecenes, such as T-2 toxin, in herds of cattle and swine.

Pigs are particularly susceptible to the trichothecene mycotoxins. T-2 toxin and/or DAS in amounts sufficient to cause toxicoses in pigs have been found in unharvested corn, silage, soybeans, and in finished feeds using corn and soybeans as ingredients. Feed refusal is generally the first sign that the feedstuffs contain trichothecene mycotoxins. The second sign is decreased weight gain. This can be accompanied with bouts of diarrhea and lethargy. Abdominal pain and teeth grinding can also occur. Hemorrhages including bleeding from the intestinal tract can occur. The trichothecenes target all cells with rapid division. These are the cells that line the gut, precursor cells that form the red and white blood cells, and precursor cells that produce spermatozoa in the testicle. Abortions have been associated with trichothecene poisoning of sows. Infertility , uterine and ovarian lesions commonly result from consumption of feed contaminated with 1 to 2 ppm of T-2 toxin. Pigs, placed on feeds that do not contain mycotoxins, recover but residual effects may be observed.

Occupational health hazards exist in handing trichothecene-contaminated grains and feed. The trichothecene mycotoxins can cause severe skin and eye irritation. Personnel should wear protective clothing and a respirator or an effective breathing mask when handling contaminated grain. Trichothecene contaminated grains and feed is often diverted to ethanol production.

Table 1. Major Mycotoxins and Toxin-Producing Fungi from Corn, Cereal, Soybeans, Peanuts, and Other Products and Some of their Effects on Animals.
Toxin or Syndrome	Fungal source	Feeds or foods affected		Possible effects on animals
Aspergillus Toxins- (primarily) Aflatoxins B₁, B₂, G₁, and G₂ (B_2a, G_2a, M₁, and M₂ are metabolites and seldom present in grain; M₁ and M₂ are important contaminants in milk)	Aspergillus flavus and A. parasiticus	Cereal Grains, peanuts, soybeans, and other foods		Hepatotoxin; carcinogenic; reduced growth rate; hemorrhagic enteritis; suppression of natural immunity to infection; decreased production of meat, milk and eggs, pulmonary mycotoxicosis
Ochraoxins (nephrotoxins)	Aspergillus alutaceaus var. alutaceus ( ochraceus) and Penicillium viridicatum	Cereal grains		Toxic to kidneys and liver; abortion; poor feed conversion, reduced growth rate, general unthriftiness; reduced immunity to infection
Sterigmatocystin	Aspergillus nidulellus, A. glaucus, A. sydowii A. versicolor and Bipolaris sorokiniiana	Cereal grains		Toxemia; carcinogenic, hepatotoxic
Termorgenic toxin	Aspergillus flavus, Aspergillus terrus, Penicillium cyclopium, and P. palitans	Cereal grains, soybeans, peanuts, and other food feeds, etc.		Tremors and convulsions, death
Penicillum Toxins (primarily) Luteoshyrin	Penicillium islandicum	Rice		Hepatotoxic, tremors and convulsions
Patulin	Penicillium urticae, P. expansum, P. clavirome, and Aspergillus clavatus	Cereal grains, apple products		Hemorrhages of lung and brain; edema toxic to kidneys; possibly carcinogenic
Rubratoxin	Penicillium rubrum			Liver damage, nephrotoxic and hemorrhage
Citrinin	Penicillium citrinum			Kidney damage
Penicillic Acid	Penicillium viridicatum and several other Penicillium sp.	Cereal grains		Similar to ochratoxin
Ergot Toxins Ergopeptines	Claviceps purpurea	Cereal Grains		Vasoconstriction, loss of extremities (ears, tail, fee, etc.), skin necrosis, agalactia
Ergovaline	Neotyphodium (Acremonium) and Epichloe sp.	Fescue		Reduced weight gain, abortion, poor survivability of offspring, fescue foot
Fusarium Toxins
Zearalenone (Estrogenic syndrome) Zearalenol	Fusarium graminearum, F. colmorum, F.equiseti		Cereal grains, soybeans	Hyperestrogenism, infertility, stunting, and even death
Emetic or feed refusal Factor, (Vomitoxin) Deoxynivalenol or DON	Fusarium graminearum (sexual state), Gibberella zeae), F. culmorum		Cereal Grains	Food refusal by swine, cats, dogs; reduction in weight gain
Other trichothecenes (T-2, HT-2, Monoacetoxyscripenol or MAS, Diactoxyscripenol or DAS)	Fusarium graminearum, F. equiseti, F. poae, F. acuminatum, F. sambucinum and F. sporotrichoides		Cereal grains, soybeans, potato	Severe inflammation of gastrointestinal tract and possible hemorrhage; edema; vomiting And diarrhea; infertility; degeneration of bone marrow; death; reduced weight gain; slow growth; sterility, abortion
Fumonishin B¹, B²	F. verticillioides, F. proliferatum		Corn	Leukoencephalomalacia “moldy corn disease” in horses, pulmonary edema in swine, neural tube defects and esophageal cancer in humans

Categories: Stored Grain, Fungi, Trichothecene, Mycotoxins, T-2, HT-2, Diacetoxyscirpenol (DAS)

Date: 11/11/2007