EVALUATION OF THE ANTIGENICITY AND IMMUNOGENICITY OF Eimeria tenella BY REPRODUCTIVE INDEX AND HISTOPATHOLOGICAL CHANGES OF CECAL COCCIDIOSIS VIRULENT LIVE VACCINE IN BROILER CHICKENS

The development of vaccine to control coccidiosis caused by Eimeria tenella (E. tenella) in chickens is intensifying because of the increasing threat of drug resistance to anticoccidial agents. It is important, therefore, to develop a reliable standard method for the assessment of vaccine afficacy particularly antigenicity and immunogenicity become crucial. Evaluation of E. tenella antigenicity and immunogenicity to some low doses can be reflected by reproductive index and histopathological changes