The effect of zinc oxide levels with different particles sizes on reproductive ‎performance of hens and roosters of broiler breeders ‎

In this research the effects of different levels and particle sizes of zinc oxide on reproductive performance of hens and roosters of broiler breeders were evaluated. A total of 200 female Ross 308 broiler breeders in a completely randomized design with 4 treatments, 5 replicates and 5 birds per each replication, and 24 male Ross 308 broiler breeders in a completely randomized design with 4 treatments, 6 replicates and one bird per each replication at 54 weeks of age were used. The experimental treatments included the diets containing 70 mg zinc from zinc oxide with large particle size (LPZnO-70), 100 mg zinc from zinc oxide with large particle size (LPZnO-100), 70 mg zinc from zinc oxide with small particle size (SPZnO-70) and 100 mg zinc from zinc oxide with small particle size (SPZnO-100). The results indicated that the experimental treatments had no significant effect on egg production, body weight, egg weight and egg yolk weight. In the entire experimental period, the egg shell thickness was significantly higher in treatment containing SPZnO than LPZnO (P<0.001). The highest and lowest fertility and hatchability ratioes were observed in treatments containing SPZnO-100and LPZnO-70, respectively. The highest semen volume was observed in roosters of treatments containing SPZnO-100 and LPZnO-100 (P< 0.05). Generally, it can be concluded that SPZnO has a more desirable effect on reproductive parameters of broiler breeders due to its higher bioavailability. Since the level of 100 mg zinc per kg of diet from both sources of zinc oxide resulted in better reproductive performance, the utilization of SPZnO-100 might be recommended.