Immunosuppression in Chickens by Aflatoxin ,

Aflatoxin, a potent natural contaminant in feedstuffs, suppressed hemagglutinin formation in chickens. The primary immune response was reduced in a dose-related fashion when aflatoxin was incorporated into the diet at levels as low as 0.625 μg. per gram. The relative sizes of the bursa of Fabricius and the thymus, the primary initiators of immunity in the chicken, were reduced by 30% and 55%, respectively, when chickens ate a diet containing 10 μg. of aflatoxin per gram of feed. The state of immunosuppression can account for the carcinogenecity of aflatoxin as well as the enhanced susceptibility to some infectious agents found during aflatoxicosis.