Development of antibodies in broiler chickens immunized with adjuvanted Eimeria tenella sporozoites

Humoral immune response elicited by administration of purified adjuvanted E. tenella sporozoites by S/C in neck region of broiler chickens in different age groups was assessed by a developed indirect ELISA. The chickens of group (T2) immunized with 25 [micro]g of antigen with Freund's Complete adjuvant (FCA) on day 2 and a booster vaccination without adjuvant on 18th day of age inducted peak IgG levels (0.616 [+ or -] 0.022) at six weeks of age post immunization (PI) with a decline (0.394 [+ or -] 0.012) at 7 weeks of age. A protective immune response against caecal coccidiosis could therefore be achieved by an immunization with adjuvanted E. tenella sporozoites in chickens of less than a week old, followed by a booster without adjuvant. Further, the performance of immunized chickens as indicated by mean weight gain (302.5 [+ or -] 13.834g), mean lesion score (1.33 [+ or -] 0.21) and mean oocyst output per gram (OPG) of faeces (53.84 [+ or -] 19.09 x [10.sup.3]) was found to be superior to the non-adjuvant vaccinated group and unimmunized infected control, however, the mean lesion score and OPG of faeces were inferior to that of medicated group. Key words: E. tenella sporozoites, FCA adjuvant, IgG levels, weight gain, lesion score.