Supplemental dietary iron glycine modifies growth, immune function, and antioxidant enzyme activities in broiler chickens

The objective of this study was to evaluate the effects of iron glycine (Fe-Gly) on growth, immune function, and serum antioxidant enzyme activities in broiler chickens. A total of 480 1-d-old broiler chickens [average body weight (BW), 45.9±0.5 g] were randomly allotted to 8 dietary treatments with 6 replicate pens and 10 broiler chickens per replicate pen. The control treatment contained 160 mg Fe/kg diet from FeSO4, while 7 other treatments consisted of 40, 60, 80, 100, 120, 140, and 160 mg Fe/kg diet from Fe-Gly. After a 21-d-feeding period, there were increasing responses to the addition of 40-160 mg Fe/kg from Fe-Gly, with the greatest ADG (quadratic, P<0.05) and ADFI (linear and quadratic, P<0.05) observed in broiler chickens fed with 100 mg Fe/kg. The weight of thymus gland increased (linear and quadratic, P<0.05) with the increasing levels of Fe as Fe-Gly, and it was greater with 160 mg Fe/kg from Fe-Gly compared with the control (P<0.05). Serum catalase (CAT), xanthine oxidase (XOD), and superoxide dismutase (SOD) increased as addition of Fe from Fe-Gly increased from 40 to 160 mg /kg (linear, P<0.05), and the SOD activity was greater in broiler chickens fed the diet containing 160 mg of Fe as Fe-Gly compared with those fed the control diet (P<0.05). The divalent metal transporter 1 (DMT1) mRNA expression was decreased with the increase of Fe as Fe-Gly in diets (linear and quadratic, P<0.05), and it was lower in broiler chicken fed the diet with 160 mg/kg Fe as Fe-Gly compared with those fed the control diet with FeSO4 (P<0.05). This study indicated that addition of Fe-Gly could obviously modify antioxidant status of broiler chickens, and moreover, improve growth performance and immune function partially.