A study was conducted to evaluate the effects of Ochratoxin A (OA) in broiler chicks challenged with Eimeria tenella oocysts. Two hundred day-old, unsexed Cobb broiler chicks were randomly divided into four treatments. Each treatment consisted of five replicates and ten chicks per replicate making the following treatments: group I: control; group II: OA (1mg/kg) daily through feed; group III: coccidia (orally inoculated with 50,000 Eimeria tenella oocysts/chick on day 21); group IV: OA (1mg/kg) daily through feed + coccidia (orally inoculated with 50,000 Eimeria tenella oocysts/chick on day 21). Six birds from each group were sacrificed on 5th, 7th, 9th and 11th day of post infection (dpi). The results showed higher mortality with severe gross lesions in cecum and greater number of fecal oocysts in groups III and IV. The gross lesions observed in group IV were characterized by distension of cecum with blood tinged content indicative of hemorrahagic typhlitis with mucosal tissue debris. Microscopically, lymphoid organs revealed severe lymphocytolysis and depletion with cellular sparcity in OA treated groups. The increased severity of lesions in the cecum of group IV was attributed to the additive effect of OA and Eimeria tenella. Cecum exhibited severe hemorrhages, presence of numerous second generation schizonts, matured merozoites and developing oocysts. Group IV showed the increase in the severity of coccidiosis which is due to immunosuppressive effect of OA. Thus, it was concluded that the expression of Eimeria tenella and its pathological effects were maximum in the presence of OA compared to the incidence of coccidiosis alone in broiler chickens.
