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 (ZnSO4).