Effect of dietary zinc level of zinc on performance and cecal lesion score in broilers infested with Eimeria tenella

摘要

Coccidiosis has great economic impact on .poultry production. One-day -old Ross 308 broiler chicks (n=144) were fed one of three levels of dietary Zn (40 as control treatment, 120 and 200 mg/kg). At 14 d of age, birds were inoculated orally with oocysts of Eimeria tenella. Body weight gain (BWG), feed intake, feed .conversion ratio and mortality rate were obtained by pen on d .21 and 42. Also at 42 d heterophil/lymphocyte (H/L) ratio, the weights of carcass, spleen and bursa of Fabricius and scoring of lesions from the intestinal Eimeria challenge were measured. Treatments did not affect performance traits at ages 21 and 42. Adding Zn to diet decreased H/L ratio and cecal lesion score (P< 0.05). Adding levels of 120 and 200 mg Zn/kg diet significantly increased the weight of bursa and spleen respectively (P< 0.05). The overall results of this study show that levels of 120 and 200 mg Zn/kg diet could be effective to enhance immunity in broilers infested with E. tenella