Study on the Relationship between Humoral Immunity and Oocyst Shedding in Eimeria Infected Chickens and the Effect of Treatment with Salinomycin

The purpose of this study is to evaluate humoral immunity response in broiler chickens with mixed Eimeria infection، before and after treating by Salinomycin. The relation between the antibody titer and oocyst shedding was also investigated. Forty Ross 308 chicks were divided into 5 groups including 2 infected groups which had been fed with drug، 2 infected groups without treatment، and one as negative control. One of the infected groups was selected from Mazandaran (denoted as category1) and the other from Hamedan (denoted as category2). The antibody titer was assessed using ELISA test. In treated chickens of category 2، OPG (oocyst per gram) had a more significant difference (P≤ 0/05) than non-treated chickens of the same category. While in category 1، there was no significant difference for this index. The results showed more virulence in category 2 compared to category 1. There was a significant difference of OD (optical density) in the negative control group compared to the other four groups (P≤ 0/05). Both groups fed with oocysts showed stimulation of the immunity system to generate antibody، however its amount was not affected by Salinomycin. The results showed that there is no significant relation between oocyst shedding and antibody titers.