Study On Influence And Mechanism Of Iron Glycine Chelate (Fe-Gly) On Laying Hens In Production Performance And Egg Quality

The main aim of this study was to investigate the effects of iron glycine chelate（Fe-Gly）on laying performance and egg quality of laying hens.Moreover,to study its mechanism and identify the suitable additive amount according to laying performance,egg quality,antioxidant enzyme activities,serum biochemical indices,Iron-related metabolizing enzymes,iron concentrations in maintain organs and eggs of laying hens.The main contents and results of the study are following:A total of 810 laying hens（Hy-Line Variety White,26 weeks old）were randomly assigned to six groups with five replicates of 27 layers.Hens in the control group received diet supplemented with 60 mg Fe/kg as ferrous sulfate（FeSO₄）,while hens in other five groups received the diet supplemented with 0,20,40,60 and 80 mg Fe/kg from Fe-Gly respectively.Moreover,glycine in every treatment had been equaled by adding extra glacine to make sure that all nutriments in diets were keep the same,except iron.Total period of the feeding trial is 9 weeks,one week for Pre-experiment,8 weeks for formal experiment.The results showed that dietary 20,40,60 mg/kgFe-Gly treatments significantly improved the egg weight（P<0.01）,compared with the control group.Moreover 60 and 80mg/kgFe-Gly treatments influenced（P<0.05）the internal egg quality（egg weight,Haugh unit,albumen height）,compared with 0 mg Fe/kg group,the laying rate in 20,40,60,80 mg/kg Fe-Gly groups were also promoted significantly（P=0.01）,whereas the control（Fe/kg as FeSO₄）group has no differences compared with the 0 mg Fe-Gly/kg group.However,dietary Fe-Gly supplementation showed few effects on the ultrastructure of eggshell.There were no differences among every treatment.The activities of CuZn-superoxide dismutase（CuZn-SOD）and total superoxide dismutase（T-SOD）,in 60,80 mg/kg Fe-Gly groups were promoted significantly（P<0.01）compared with 0 mg Fe/kg group.The succinate dehydrogenase（SDH）levels of liver and spleen in 60 mg/kg Fe-Gly group was promoted（P<0.05）,compared with the 0 mg/kg Fe-Gly group,whereas the control（Fe/kg as FeSO₄）group has no differences compared with the 0 mg/kg Fe-Gly group.Furthermore,in this study,the total protein（TP）（P<0.01）and concentrations of Fe in serum,liver,kidney,spleen,ovary were increased significantly in 60 and 80 mg/kg Fe-Gly groups compared with the control（P<0.01）.The concentrations of Fe in the yolk and albumen in 60,80 mg/kg Fe-Gly groups were also increased significantly,compared with the control.In addition,there were trends that transferrin（TF）and divalent mental transport 1（DMT1）genes’expressions in liver and duodenum was decreased with the increase of Fe as Fe-Gly in diets,and compared with the control,TF（P<0.01）and DMT1（P<0.01）genes’expression were lower in 60 mg/kg Fe-Gly group.In addition,The expressions of ferroportin 1（FPN1）of duodenum in 60 and 80 mg/kg Fe-Gly groups were influenced（P<0.05）,compared with the control.Moreover,when using Fe-Gly（40 mg/kg Fe）as iron supplement in diets of laying hens,compareed FeSO₄（60 mg/kg Fe）,there were no significant differences in laying rates,feed conversion ratio,egg quality,antioxidant enzyme activity,iron enrichment in serum,liver,kidney,and the expressions of iron transport genes in liver and duodenum in laying hens.In conclusion,as a kind of iron supplement,Fe-Gly could be more benefit for improving laying rate,egg weight,Haugh unit,albumen height,antioxidant enzyme activity,the concentrations of iron in main tissue and organs,protein synthesis in body and the expressions of iron transport genes in liver and duodenum in laying hens,increasing SDH activity,promoting protein transports and iron enrichment,compared with FeSO₄.Moreover,in the suitable dosage（40-80 mg Fe/kg diet）,when using lower dosage of Fe-Gly（40 mg Fe/kg diet）as iron supplement in diets of laying hens,compared with FeSO₄（60 mg Fe/kg diet）,there were no significant differences in laying rates,feed conversion ratio,haugh unit,albumen height,color of yolk,eggshll quality,antioxidant enzyme activity,iron enrichment in serum,liver,kidney,and the expressions of iron transport genes in liver and duodenum of laying hens.As a kind of iron supplement in diets,Fe-Gly could be superior to FeSO₄ for laying hens.