Effects Of Vitamin E Supplementation On Performance,egg Quality,lipid Metabolism And Antioxidation In Laying Hens Fed A Diet Containing Aging Corn

The study investigated the effects of vitamin E(VE)supplementation on performance,egg quality,nutrient utilization,lipid metabolism and antioxidation in Lohmann laying hens fed a diet containing aging corn.The experiment consisted of a 2×3 factorial design with two corn types(normal corn and aging corn,aging corn completely replace normal corn)and three VE concentrations(0,20,100mg/kg),including six treatment diets.A total of 216 Lohmann laying hens(50-wk-old)were randomly allocated into 6 treatment diets for 12 weeks.Each treatment had six replicates with 6 hens.The results showed:(1)Aging corn significantly decreased average daily feed intake of wk1-4,5-8,1-12(P< 0.01),decreased egg weight of wk1-4(P< 0.05),9-12(P< 0.01),1-12(P< 0.05).Dietary VE supplementation had no significant influences on feed intake and egg weight of each stage(P> 0.05).Compared with 0mg/kg VE,100mg/kg VE significantly increased egg production(P< 0.01)and decreased feed conversion ratio(P< 0.01)of wk9-12.(2)Aging corn significantly decreased a value of eggshell(P< 0.05),albumen quality(albumen height and Haugh unit)(P< 0.05),egg yolk color and vitelline membrane strength(P< 0.01)at the end of 4 week,significantly decreased egg yolk color(P< 0.01)and vitelline membrane strength(P< 0.05)at the end of 8 week,significantly decreased egg yolk color(P< 0.01)at the end of 12 week.VE had no significant influences on egg quality at the end of 4 week(P> 0.05),100mg/kg VE could significantly increased b value of eggshell and vitelline membrane strength(P< 0.01)at the end of 8 week,20 and 100mg/kg VE could significantly increased vitelline membrane strength(P< 0.01)at the end of 12 week.There was a significant interactive effect on egg yolk color(P< 0.05)between corn and VE at the end of 8 week.(3)Aging corn significantly decreased the apparent digestibility of crude fat(P< 0.01).Compared with 0mg/kg VE,20mg/kg VE significantly increased the apparent digestibility of dry matter(P< 0.01),energy(P< 0.01),crude fat(P< 0.01)and crude protein(P< 0.05),100mg/kg VE significantly increased the apparent digestibility of dry matter and energy(P< 0.01).Both aging corn and VE had no significant influences on jejunum morphology(P> 0.05).(4)Both aging corn and VE had no significant influences on serum biochemical parameters(P> 0.05).(5)Aging corn significantly decreased the content of low density lipoprotein cholesterol(LDL-C)(P< 0.05)in liver.VE had no significant influences on the content of crude fat and cholesterol(P> 0.05)in liver.Aging corn significantly decreased the content of total cholesterol(TC)(P< 0.05),LDL-C(P< 0.01)and very low density lipoprotein cholesterol(VLDL-C)(P< 0.05)in serum.Compared with 0 and 20mg/kg VE,100mg/kg VE significantly increased the content of LDL-C and VLDL-C(P< 0.05)in serum.Aging corn significantly decreased chemokine-like receptor 1(CMKLR1)m RNA expression level(P< 0.05)in liver.VE had no significant effect on liver Acetyl-Co A carboxylase(ACC),lipoprotein lipase(LPL),fatty acid synthase(FAS)and CMKLR1 m RNA expression level(P> 0.05).(6)Aging corn significantly increased the content of stearic acid(C18:0)(P< 0.01)in egg yolk,significantly decreased the content of oleic acid(C18:1)and docosahexaenoic acid(C22:6)(P< 0.05),significantly increased the content of total saturated fatty acid(SFA)(P< 0.01),significantly decreased the content of total monounsaturated fatty acid(MUFA)(P< 0.05).VE had no significant influences on the fatty acid(FA)profile and cholesterol content of egg yolk(P> 0.05).There was a significant interactive effect on the content of C18:1(P< 0.05)between corn and VE.(7)The degree of hepatocyte swelling and steatosis in aging corn diets was more serious than that in normal corn diets,its pathological score of liver was more than 2 points,the pathological score of normal corn diets was 2 points or below 2 points.Whether supplementation of VE in normal corn or aging corn diets,the pathological score of liver decreased with increasing VE concentrations.(8)Aging corn significantly increased the content of MDA(P< 0.05)in liver,decreased superoxide dismutase(SOD)activity(P< 0.05)in liver,increased the content of MDA(P< 0.05)in serum,decreased glutathione peroxidase(GSH-PX)activity(P< 0.01)in serum,decreased GSH-PX activity(P< 0.05)in ovary.20 and 100mg/kg VE significantly increased GSH-PX activity(P< 0.05)in liver,100mg/kg VE significantly increased SOD activity(P< 0.05)in serum,both 20 and 100mg/kg VE could significantly increased GSH-PX activity(P< 0.01)in serum.Aging corn increased the content of peroxidation product including malondialdehyde(MDA)and protein carbonyl in egg yolk,but not significantly(P> 0.05).100mg/kg VE could significantly decreased the content of MDA(P< 0.05)in egg yolk.Aging corn significantly increased SOD1 m RNA expression level(P< 0.01)in ovary.100mg/kg VE could significantly increased SOD1 m RNA expression level(P< 0.01)both in liver and serum.There was a significant interactive effect on GSH-PX and SOD1 m RNA expression level(P< 0.05)in ovary between corn and VE.The experiment results showed: aging corn significantly decreased production performance and egg quality of laying hens,decreased nutrient utilization,affected lipid metabolism in serum and liver,caused damages of liver and decreased the antioxidant function of laying hens.The supplementation of VE(20 and 100mg/kg)could improve production performance,egg quality and nutrient utilization of laying hens,also affected serum lipid metabolism,protected liver and enhanced antioxidant function.But the effects of VE supplementation were independent of those of age of corn and were unable to counteract the negative effects of feeding aging corn.