Effects Of Iron Glycine On Physiological And Biochemical Indicators And Related Gene Expression In Broiler Chickens

The objective of this study was to evaluate the effects of iron glycine(Fe-Gly) on growth performance, immune organ index, blood biochemical indicators, iron concentration of tissues, antioxidant enzyme activities, and related gene mRNA expression in broiler chickens, in order to display the effects and appropriate dosage of iron glycine which as a supplement added to diets.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 Fe SO4, while 7 other treatments consisted of 40, 60, 80, 100, 120, 140, and 160 mg Fe/kg diet from Fe-Gly. After a 21-feeding period, there were increasing responses to the addition of 40 to 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 100 mg Fe/kg. 80 mg Fe/kg and 100 mg Fe/kg Fe as Fe-Gly improved the average daily gain(ADG)(P < 0.05) and 100 mg Fe/kg from Fe-Gly enhanced average daily feed intake(ADFI)(P < 0.05) of broilers compared with the control. The thymus gland index 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). The concentration of hemoglobin(HGB), hematocrit(HCT) and serum ferrum were increased with the increasing addition of Fe-Gly(linear and quadratic, P < 0.05) to diets. Compared with the control, the concentration of HGB and serum ferrum were increased in broiler chickens fed the diet containing 160 mg of Fe as Fe-Gly(P < 0.05). The iron concentration of tissues including heart, liver, spleen, and tibia were all linearly and quadratically increased with the Fe-Gly dosage in diets(P < 0.05). Compared with control, the iron concentrations of liver were greater in broiler chickens fed the diet containing 100, 120, 140, and 160 mg Fe/kg Fe as Fe-Gly and tibia was greater in 120 and 140 mg Fe/kg. 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 addition of 120 and 140 mg Fe/kg from Fe-Gly increased serum CAT activities(P < 0.05), and SOD activities of chickens were increased by the addition of 120, 140 and 160 mg Fe/kg Fe as Fe-Gly to diet(P < 0.05) compared with the control. The Hepcidin mRNA expression was increased in broiler chickens fed the diet containing 140 and 160 mg Fe/kg Fe as Fe-Gly(P < 0.05) and 40-100 mg Fe/kg fed with Fe-Gly was significantly decreased compared with the control. The divalent metal transporter 1(DMT1) m RNA expression was significantly decreased in 100, 120, 140 and 160 mg Fe/kg from Fe-Gly treatment groups(P < 0.05). However, increased DMT1 m RNA level was observed in the addition of 40 and 60 mg Fe/kg from Fe-Gly(P < 0.05) compared with control group.This study indicated that addition of Fe-Gly could obviously modify growth performance, immune organ index, blood biochemical indicators, iron concentration of tissues, and antioxidant enzyme activities in broiler chickens, and moreover, Fe-Gly might be a superior to Fe SO4 as a supplement in chickens. In addition, the appropriate supplemental level of Fe-Gly should be 80-100 mg Fe/kg in growth performance of broiler chencken, but which should be reconsidered with the actual need in other items.