Development of immunity against Eimeria tenella in broilers following immunisation with sporulated oocyst antigen

摘要

Broiler chicks at the age of 2 days were immunized with Eimeria tenella sporulated oocyst antigen (25 #mu#g/chick) with or without adjuvants, and a booster dose was given at 18 days of age. These birds were challenged with 10 x 103 sporulated oocysts of homologous species at the age of 30 days. Chicks immunized with antigen adsorbed in aluminium hydroxide gel showed better protection in terms of reduction in oocyst output (77.05%), mortality (1) and mean lesion scores (+2). Peak antibody titre (1:640)as assessed by tube agglutination test was also observed on day 28 postimmunization in chicks immunized with antigen adsorbed in aluminium hydroxide gel. However, antigen emulsified in Freund's complete adjuvant (FCA) produced maximum cell-mediated immune response starting at day 16 until day 35 postimmunization. Both immediate and delayed types of cell-mediated immune responses were observed in the immunized chicks.