Saravanan, S.Palanivel, K.M.Harikrishnan, T.J.Srinivasan, P.Selvaraju, G.TANUVAS2016-06-132016-06-132014-07http://krishikosh.egranth.ac.in/handle/1/67228Aim : To assess the humoral immune response of Eimeria tenella sporozoites in broiler chickens by a developed enzyme linked immunosorbent assay (ELISA) and the efficacy in terms of bodyweight, lesion score and oocysts excretion in immunized broilers. Materials and Methods: Purified live E. tenella sporozoites were administered subcutaneously in neck region of broiler chickens in the early life (first week) at different concentrations. The potency of the sporozoite vaccine as assessed by IgG levels and the performance in immunized broilers as assessed by body weight, lesion score and oocysts excretion in faeces after challenge with 10, 000 E. tenella live oocysts at 49 days of age were evaluated. Results: The chickens of group (T4) immunized with 20 μg of antigen on day 6 showed an increase in IgG levels (0.161±0.004) two weeks post immunization (PI) peaking (0.399± 0.016) at 5 weeks PI. The mean weekly weight gain (g) after challenge, at 56 days of age was high in T4 (148±4.751 g) with a low mean lesion score (2.5±0.22) and mean oocyst output (x10^3 oocytes per gram (OPG) in faeces (100.3± 45.72) when compared to unimmunised infected controls. Conclusion: An early but partial immune response against caecal coccidiosis could be achieved by immunization with E.tenella specific sporozoites in chickens of less than a week old. Moreover, the performance of immunized chickens as indicated by weight gain, lesion score and oocyst output was found to be superior to the unimmunized infected controls.enBody weightBroiler chickensEimeria tenella sporozoitesELISAIgG levelsLesion scoreArticle