Effects Of Different Selenium Sources And Levels On Growth Performance,Antioxidant Indexes And Trace Element Deposition Of Laying Hens

In order to compare the different selenium source and level of Hy-Line grey laying hens production performance,egg quality,serum and egg yolk antioxidant index effects and some trace elements,for laying hens added selenium precision in the actual production to provide practical basis.504 20-week-old Hy-Line grey laying hens were selected and randomly divided into 7 groups with 8 repeats in each group and 9 laying hens in each repeat.The selenium sources were selenite(SS),0.15,0.3,and 0.45 mg/kg of yeast selenium(Selenium yeasy,SY)and nano-slenium(Nano-slenium,NS).The pre-feeding period was 1 week,and the formal feeding period was 5 weeks.The test results were as follows:1.Dietary supplementation of different selenium sources and levels had no significant difference in the laying rate,average daily feed intake and average daily egg weight of Hy-Line grey laying hens(P>0.05),but there was significant difference in the feed egg ratio(P<0.05).Compared with 0.3mg/kg SS,the feed egg ratio of0.3mg/kg NS was significantly increased(P<0.05).2.Dietary supplementation of different selenium sources and levels had no significant difference in egg weight,egg shape index,eggshell strength,Albumen height,yolk color and Haugh unit of Hy-Line grey laying hens(P>0.05),but there was significant difference in eggshell thickness(P<0.05).Compared with 0.3mg/kg SS,there was no significant difference in egg quality between different levels of YS or NS(P>0.05).Compared with YS,the eggshell thickness of 0.3mg/kg NS was significantly higher(P<0.05).Different levels of YS and NS had significant interaction effect on yolk color(P<0.05).3.Dietary supplementation with different selenium sources and levels had no significant difference in serum total antioxidant capacity and malondialdehyde of Hy-Line grey laying hens(P>0.05),but there were significant difference in serum glutathione catalase and total superoxide dismutase(P<0.01).Compared with 0.3mg/kg SS,serum glutathione catalase activity in 0.3mg/kg NS was significantly decreased(P<0.01),and serum superoxide dismutase of 0.3mg/kg YS or NS was significantly increased(P<0.01).There was no significant difference in malondialdehyde of egg yolk stored at room temperature for 3 days(P>0.05),but there were significant differences in total antioxidant capacity and total superoxide dismutase of egg yolk(P<0.01).Compared with 0.3mg/kg SS,the yolk total antioxidant capacity of 0.3mg/kg YS or NS was significantly decreased(P<0.01),and the yolk total superoxide dismutase of 0.3mg/kg YS or NS was significantly increased(P<0.01).Total superoxide dismutase in 0.45 mg/kg NS was significantly lower than other levels of NS.Different levels of YS and NS had significant interaction effect on yolk total superoxide dismutase(P<0.05).There was no significant difference in total antioxidant capacity of egg yolk stored at room temperature for 10 days(P>0.05),but significant difference in total superoxide dismutase and malondialdehyde in egg yolk(P<0.05).Compared with 0.3mg/kg SS,the yolk total superoxide dismutase of0.3mg/kg YS was significantly decreased(P<0.05),and the yolk malonaldehyde of0.3mg/kg YS was significantly decreased(P<0.05).The total superoxide dismutase activity of egg yolk of 0.45 mg/kg YS was significantly higher than other levels of YS.Compared with the antioxidant indexes of egg yolk stored at room temperature for 3days,the total antioxidant capacity and total superoxide dismutase of egg yolk stored at 10 days were significantly reduced,and malondialdehyde was significantly increased.4.Dietary supplementation of different selenium sources and levels had no significant difference in serum manganese and copper content of Hy-Line grey laying hens(P>0.05),but had very significant difference in selenium,zinc and iron content(P<0.01).Compared with 0.3mg/kg SS,the selenium content of 0.3mg/kg YS or NS was significantly increased(P<0.01),and the zinc and iron content of 0.3mg/kg YS or NS was significantly decreased(P<0.01).The serum selenium content of 0.15 mg/kg YS was significantly lower than that of other levels of YS.The serum zinc content of0.3 mg/kg NS was significantly lower than other levels of NS.Different levels of YS and NS had significant interaction effect on serum zinc content(P<0.01).There were significant differences in selenium,zinc,iron and copper content in egg yolk(P<0.01),and significant differences in manganese content(P<0.05).Compared with 0.3mg /kg SS,the manganese content of 0.3mg/kg YS was significantly decreased(P<0.01).The yolk selenium content of 0.15mg/kg YS was significantly lower than other levels of YS,the yolk zinc and iron content of 0.45mg/kg YS was significantly lower than other levels of YS,and the copper content in the yolk increased significantly with the increase of the added level of YS.The content of selenium in egg yolk increased significantly with the increase of NS addition level,and the content of zinc in egg yolk of 0.15mg/kg NS was significantly lower than other levels of NS.Different levels of YS and NS had very significant interaction effect on selenium and manganese content(P<0.01).Above all,compared with 0.3 mg/kg of SS,dietary supplementation of different levels of YS or NS had no significant difference in the production performance of Hy-Line grey laying hens(except 0.3 mg/kg NS significantly increased the feed egg ratio),egg quality and serum antioxidant capacity increased to a certain extent,serum selenium in egg yolk and the concentration of zinc,manganese,iron,copper had a certain change.