The effect of nitrofurazone on the thiamin status of chickens.

Nitrofurazone, given orally at doses of 10 and 20 mg/kg for seven days, decreased the activity of erythrocyte transketolase (TK) and increased the activation of TK by thiamin pyrophosphate (TPP effect %). Nitrofurazone also decreased the feed intake and growth of the chickens, and increased the concentrations of lactate and pyruvate of their blood. It was concluded that nitrofurazone has induced thiamin deficiency in the treated birds. Pair-feeding experiments showed that the decreased growth was due to anorexia, and that the effects produced by nitrofurazone treatment on the thiamin status were attributable to the drug, per se, and not to anorexia. Thiamin (100 micrograms/kg, injected subcutaneously), when given concomitantly with nitrofurazone, was effective in preventing the development of thiamin deficiency.