Effects of zinc glycine chelate on growth, hematological, and immunological characteristics in broilers

Three hundred sixty healthy Ross x Ross 1-day-old broilers were used to study the effects of zinc glycine chelate (Zn-Gly) on growth performance, hematological, and immunological characteristics. All broilers were randomly assigned into six treatments. Diets were as follows: (1) control (containing 29.3 mg Zn kg(-1) basic diet [0-3 weeks] and 27.8 mg Zn kg(-1) [4-6 weeks]); (2) basic diet plus 30 mg Zn kg(-1) from Zn-Gly; (3) basic diet plus 60 mg Zn kg(-1) from Zn-Gly; (4) basic diet plus 90 mg Zn kg(-1) from Zn-Gly; (5) basic diet plus 120 mg Zn kg(-1) from Zn-Gly; (6) positive control, basic diet plus 120 mg Zn kg(-1) from zinc sulfate (ZnSO(4)). After the 21- and 42-day feeding trials, the results showed that both of Zn-Gly and ZnSO(4) could improve the growth performance of broilers, with the greatest average daily feed intake observed in the broilers fed 90 mg Zn kg(-1) from Zn-Gly, but the greatest average daily gain observed with 120 mg Zn kg(-1) from Zn-Gly (0-3 weeks) and 90 mg Zn kg(-1) from Zn-Gly (4-6 weeks). Adding additional Zn-Gly improved the levels of immunoglobulins (IgA, IgM, and IgG) and the contents of total protein and Ca in serum and increased the immune organs index especially with 90 mg Zn kg(-1) as Zn-Gly. However, there were no significant differences in responses to complements (C3 and C4) and albumin in serum among the treatments.