Assessment of protection against Eimeria tenella in broiler breeders conferred by a live anticoccidial vaccine, and effects of vaccination on early pullet growth

Summary Vaccination with live anticoccidial vaccine is widely practiced to control coccidiosis in broiler breeders. However, vaccination during feed restriction may affect early pullet growth. Two experiments were conducted using Cobb-500-FF broiler breeder female-chicks to evaluate the level of immunity generated by a live anticoccidial vaccine, and to study the effects of vaccination with low doses of E. acervulina, E. tenella, and E. maxima on early growth of chicks during feed restriction. In the first experiment, unvaccinated and vaccinated chicks were allocated to battery cages at DPV (days post-vaccination) 28, 35, 42, 49 and 56, and challenged with 100,000 oocysts of E. tenella. In the second experiment, a total of 280 day-old chicks were allocated to 2 groups and vaccinated with either 0 or 500 oocysts each of 3 species of Eimeria. Cecal gross lesion scores and dropping pan scores were significantly reduced (P