effect of different levels of zinc supplementation on some productive parameters of broiler breeder

in order to investigate the effect of different levels of zinc on some productive parameters of broiler breeder, an experiment was conducted with 300 hens and 40 roosters of ross 308 strain (40 wk old) in 12 week period in completely randomized design with 4 treatments, 5 replicates and 15 hens and 2 roosters in each replicate. treatments consisted of 4 different levels of zinc (80, 110, 140 and 170 mg zinc/kg diet) in which the dietary zinc was supplied from zinc sulfate. zinc supplementation significantly improved egg production, egg weight, egg shell quality and feed conversion ratio during the experiment. production percentage and feed conversion ratio had the best results in 170 mg zinc/kg diet and the best results of egg weight and egg shell quality were observed in 140 and 170 mg zinc/kg diet. zinc supplementation improved the weight and quality of neonatal chicks. by increasing levels of zinc in the diet, weight of bursa fabricius of chicks and weight of heart of broiler breeders increased. the results of this experiment suggest that supplementation of broiler breeder diet with zinc could improve performance and quality of neonatal chicks.