Effects of Zinc Glycinate on Productive and Reproductive Performance, Zinc Concentration and Antioxidant Status in Broiler Breeders.

Abstract

An experiment was conducted to investigate the effects of zinc glycinate (Zn-Gly) supplementation as an alternative for zinc sulphate (ZnSO4) on productive and reproductive performance, zinc (Zn) concentration and antioxidant status in broiler breeders. Six hundred 39-week-old Lingnan Yellow broiler breeders were randomly assigned to 6 groups consisting of 4 replicates with 25 birds each. Breeders were fed a basal diet (control group, 24mg Zn/kg diet), basal diet supplemented with 80mg Zn/kg diet from ZnSO4 or basal diet supplemented with 20, 40, 60 and 80mg Zn/kg diet from Zn-Gly. The experiment lasted for 8weeks after a 4-week pre-test with the basal diet, respectively. Results showed that Zn supplementation, regardless of sources, improved (P < 0.05) the feed conversion ratio (kilogram of feed/kilogram of egg) and decreased broken egg rate, and elevated (P < 0.05) the qualified chick rate. Compared with the ZnSO4 group, the 80mg Zn/kg Zn-Gly group significantly increased (P < 0.05) average egg weight, fertility, hatchability and qualified chick rate, whereas it decreased (P < 0.05) broken egg rate. The Zn concentrations in liver and muscle were significantly higher (P < 0.05) in 80mg Zn/kg Zn-Gly group than that in ZnSO4 group. Compared with ZnSO4 group, 80mg Zn/kg Zn-Gly group significantly elevated (P < 0.05) the mRNA abundances of metallothionein (MT) and copper-zinc superoxide (Cu-Zn SOD), as well as the Cu-Zn SOD activity and MT concentration in liver. Moreover, the 80mg Zn/kg Zn-Gly group had higher (P < 0.05) serum T-SOD and Cu-Zn SOD activities than that in the ZnSO4 group. This study indicated that supplementation of Zn in basal diet improved productive and reproductive performance, Zn concentration and antioxidant status in broiler breeders, and the 80mg Zn/kg from Zn-Gly was the optimum choice for broiler breeders compared with other levels of Zn from Zn-Gly and 80mg/kg Zn from ZnSO4.