Effect of aflatoxin B1 on the delayed type hypersensitivity and phagocytic activity of reticuloendothelial system in chickens

Efforts were made to see the effect of feeding aflatoxin B₁ at 0.3 ppm level on various aspects of the immune system in chickens. The birds were fed aflatoxin B₁ (AFB₁) mixed ration from 0 to 6 weeks of age and thereafter normal feed was given up to 12 weeks of age. The delayed type hypersensitivity reaction of these birds was assessed by contact sensitivity to Dinitrofluorobenzene. The dietary AFB₁ significantly suppressed the cell mediated immune response at all the three periods tested (30, 45 and 60 days of age). The toxin showed residual effect on immunity as the suppression of cell mediated immunity was maximum three days after the withdrawal of toxin from the feed. The effect of AFB₁ on the phagocytic status of reticulo endothelial system (RES) was assessed by colloidal carbon clearance test at various intervals. The residual effect of toxin was observed on RES too as phagocytic index of AFB₁ fed birds was significantly lowered up to 45 days of age.