Evaluating zinc glycine chelate in Cherry Valley Ducks: Responses of growth performance, nutrient utilization, serum parameters, antioxidant status, meat quality and zinc accumulation

Abstract

The current study was conducted to investigate whether Zinc glycine chelate (Zn-Gly) is superior to Zinc sulfate (ZnSO4) on the growth performance, nutrient utilization, serum parameters, meat quality, zinc accumulation, and antioxidant capacity of meat ducks. A total of 896 one-d-old Cherry Valley Ducks were randomly allocated into 7 dietary treatments with 8 replicates of 16 ducks. Treatments consisted of basal diet (NC); Basal diet with either 120 mg/kg Zn from ZnSO4 (PC) or 15, 30, 60, 90, 120 mg/kg Zn from Zn-Gly (PZ1, PZ2, PZ3, PZ4, PZ5 respectively). After the 14- and 35-day feeding trials, both Zn-Gly and ZnSO4 improved (p < 0.05) the body weight (BW) of meat ducks, with the greatest BW observed in the ducks fed PZ4 and PZ5 diet on day 14 and 35, respectively. Ducks fed PZ1, PZ2, PZ3, PZ4 and PZ5 diets had higher (p < 0.05) average daily gain (ADG) than those fed the NC diet during days 0−14. During days 15−35 and 1–35, the supplementation of PZ1, PZ2, PZ3, PZ4 and PZ5 diet increased ADG compared with the NC diet (p < 0.05). Notably, the PZ5 diet increased (p < 0.05) ADG during days 15−35, compared with the PC diet. Increasing Zn-Gly content in the diet increased (p < 0.05) average daily feed intake (ADFI) in ducks during days 15−35. Compared with the NC diet, the apparent utilization of energy, protein, DM and ash were increased with dietary Zn concentration up to 90 and 120 mg/kg (p < 0.05). However, there was no significant difference in the apparent utilization of energy, protein, DM and ash between the PZ5 diet and the PC diet (p> 0.05). Additional Zn-Gly increased (p < 0.05) the activity of alkaline phosphatase (ALP) and improved the content of Ca in serum especially with 120 mg Zn/kg as Zn-Gly. The results showed that PZ5 diet improved (p < 0.05) the activity of CuZnSOD (Cu, Zn superoxide dismutase) in serum and liver compared with other diets including the PC diet. Zn-Gly supplementation reduced luminance (L*) value and drip loss (p < 0.05). In conclusion, supplementing at least 90 mg Zn/kg in the form of Zn-Gly was as effective in stimulating growth, improving nutrient utilization as when a high concentration of ZnSO4 (120 mg Zn/kg) was included in the diet.