Effects of zinc glycine chelate on growth performance, carcass characteristics, bone quality, and mineral content in bone of broiler chicken

A total of 250 one-day-old male broilers (Ross 308) were used to investigate the effects of dietary Zn-Gly (zinc glycine chelate) supplementation on growth performance, carcass characteristics, bone quality, and mineral content in bones. All broilers were randomly assigned to five treatment groups, each of which was replicated five times (10 birds in each cage). 5 groups were formed: control negative - CN (corn wheat and soybean meal control diet with no supplementation of Zn), control positive - CP (CN + 100 mg of Zn as oxide/kg of diet), and 3 groups with Zn-Gly supplementation at three doses: 25, 50, or 100 mg kg(-1) (CN +25, 50, or 100 mg of Zn as glycine chelate/kg of diet). The experimental diets were fed to chicks for over 6 weeks. In the study, a positive trend to gain body weight and the weight of breast, thigh, and drumstick muscles was observed when organic Zn was introduced, in particular at a dose of 50 and 25 mg. The addition of Zn, regardless of its source, had an effect on the increase (P<0.05) in the intake of feed. A considerable increase in values such as cross-sectional area (A), second moment of inertia (Ix), and mean relative wall thickness (MRWT) was found both in the femur and in the tibia in the group supplemented with 50 mg Zn-Gly. The use of Zn-Gly improved the quality of the tibia and femur and their strength parameters, perhaps due to the increased deposition of Ca and P in bones. The addition of Zn-Gly increased (P < 0.05) the accumulation of Zn in bones. In conclusion, these results suggest that the supplementation of Zn-Gly in amounts lower than recommended has no negative effect on the production performance of Ross broiler chickens, which in turn suggests that such an amount of Zn is sufficient to ensure the optimum body weight and positive production performance and is the condition of correct ossification and mineralisation of the bone tissue. (C) 2016 Elsevier B.V. All rights reserved.