Effects of Maternal Zinc Glycine on Mortality, Zinc Concentration, and Antioxidant Status in a Developing Embryo and 1-Day-Old Chick.

Abstract

This study was conducted to investigate the effects of maternal zinc glycine (Zn-Gly) supplementation as an alternative for zinc sulfate (ZnSO4) on mortality, zinc (Zn) concentration, and antioxidant status in a developing embryo and 1-day-old chick. Six hundred 39-week-old broiler breeders were randomly assigned to 6 treatments, each treatment including 5 replicates with 20 birds each. Six treatments received a basal diet (control, 24mg Zn/kg diet) or a basal diet supplemented with ZnSO4 (80mg Zn/kg) or Zn-Gly (20, 40, 60, or 80mg Zn/kg), respectively. The experiment lasted for 8weeks after a 4-week pre-experiment with a basal diet. At the last week, 100 eggs per replicate were randomly collected for incubation. Compared with the control treatment, Zn supplementation decreased (P<0.05) embryo mortalities of the late stage and the whole period, increased (P<0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick, and improved (P<0.05) antioxidant status in the embryo of d19 and 1-day-old chick. Compared with the ZnSO4 treatment, 80mg Zn/kg Zn-Gly treatment significantly decreased (P<0.05) the late stage embryo mortality and increased (P<0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick. The 80mg Zn/kg Zn-Gly treatment significantly increased (P<0.05) copper-zinc superoxide dismutase activity in d19 embryo and 1-day-old chick, total superoxide dismutase activity in 1-day-old chick, and copper-zinc superoxide dismutase messenger RNA (mRNA) abundance of d9 embryo and 1-day-old chick than that in ZnSO4 treatment. The liver metallothionein concentration of the developing embryo and 1-day-old chick and its mRNA abundance of d19 embryo were also significantly increased (P<0.05) in the 80mg Zn/kg Zn-Gly treatment in comparison with ZnSO4 treatment. In conclusion, maternal Zn supplementation decreased embryo mortalities of the late stage and the whole period by increasing liver Zn concentration and antioxidant status in d19 embryo and 1-day-old chick, and 80mg Zn/kg from Zn-Gly treatment was the optimum choice.