Feed refusal trichothecenes

Contamination occurs primarily in wheat, barley, rye, and maize. Type A trichothecenes include mainly T-2 toxin, HT-2, and diacetoxyscirpenol (DAS) mycotoxins of the group B include mainly 4-deoxynivalenol (DON), commonly known as vomitoxin, and nivalenol (NIV). Toxic effects include nausea, vomiting, visual disorder, vertigo, throat irritation, and feed refusal in farm animals. The most toxic is T-2, followed by DAS and NIV, with DON being the least toxic in acute toxicity studies but the most widespread in grains worldwide and therefore the most studied. Issues related to chemical and physical data, occurrence, toxicity, absorption, distribution, and metabolism of trichothecenes are reviewed in WHO (89) and IARC (34). Physicochemical data for some selected Fusarium toxins is given by Sydenham et al. (90). The molecular structures of the main trichothecenes are shown in Fig. 9. 

Trichothecences are a class of structurally similar mycotoxins produced principally by Fusarium molds. These cyclic compounds are of interest to feed manufacturers because they can cause feed refusal or reduced feed efficiencies in some animal species (1,2,3). Several approaches have been reported for the analysis of trichothecenes in feeds and feed ingredients. Trimethylsilyl derivatives of the trichothecenes have been formed and the derivatives measured by gas chromatography using a flame ionization detector (4,3,6,7). Other workers obtained improved... 

D. I Toxidty. Voluntary feed refusal often prevents full expression of oral toxicosis from conta-minated feeds. Fiowever, iJosing studies using parenteral injection and oral administration reveal that trichothecenes are potent toxicants. 

Deoxynivalenol, also known as DON or vomitoxin, is a trichothecene mycotoxin that affects brain neurochemistry (e.g., dopamine and 5-hydroxyindolacetic acid), leading to nausea and appetite suppression. Feed refusal or decreased feed intake occurs through a learned response known as "taste aversion."... 

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