Study On The Vitamin E Alleviating The Effects Induced By Protein-oxidized Soybean Meal In Laying Hens

Storage can induce protein oxidation of soybean meal,which would result in negative impacts on poultry production.Vitamin E(VE)has excellent anti-oxidation,anti-stress and immunity.At present,there is no research focusing on the effects of protein-oxidized soybean meal on laying hens and the regulatory effects of VE.Therefore,soybean meal was stored at room temperature for 30 days,leading to its protein oxidize in this experiment,and Hyline Brown laying hens were selected as the experimental animal to investigate the negative effects of protein-oxidized soybean meal on production performance,digestive function,intestinal health,immune function and antioxidant capacity,and also to explore the regulatory effect of synthetic and natural VE supplementation into the diet,providing a reference for alleviating the adverse effects of protein-oxidized soybean meal on laying hens and improving the production level of laying hens through nutrition manipulation.This paper is divided into three parts,as follows:Trial Ⅰ aimed to study the adverse effects of protein-oxidized soybean meal on laying performance,digestive function,and egg quality of laying hens,and the alleviating effects of VE.A total of 384 Hyline Brown laying hens(41 weeks of age)were randomly divided into 4 groups with 8 replicates of 12 hens each.Laying hens were fed a basal diet with refrigerated fresh soybean meal(control group),protein-oxidized soybean meal diet(protein-oxidized soybean meal group;soybean meal was stored at room temperature for 30 days),and the stored soybean meal diet supplemented with either 100 mg/kg either synthetic VE(synthetic VE group)or natural VE(natural VE group),for 6 weeks after a 1-week period of pertest.The results were presented as follows:compared with the control group,synthetic and natural VE significantly reduced the average daily feed intake of laying hens(P<0.05);compared with the protein-oxidized soybean meal group,natural VE inclusion significantly increased laying rate(P<0.05),whereas reduced feed-to-egg ratio of laying hens(P<0.05).Compared with the protein-oxidized soybean meal group,VE supplementation irrespective of its form increased the high-density lipoprotein cholesterol concentration in the serum of laying hens(P<0.05),and synthetic VE supplementation significantly reduced low-density lipoprotein cholesterol concentration(P<0.05).Compared with the control group,protein-oxidized soybean meal significantly reduced the trypsin activity in the ileal chyme(P<0.05),which was recoverd to normal level by natural VE supplementation(P>0.05);compared with the protein-oxidized soybean meal group,both inclusion of natural and synthetic VE significantly increased the trypsin activity in the jejunal chyme of laying hens(P<0.05).Compared with the control and protein-oxidized soybean meal groups,synthetic VE supplementation significantly increased the protein height and haugh unit in the eggs of laying hens(P<0.05).Trial Ⅱ aimed to study the effects of VE in alleviating the intestinal health and immune function damage of laying hens fed with protein-oxidized soybean meal.The experimental design was the same as the experment one.The results were shown as follows:compared with the control and protein-oxidized soybean meal groups,the addition of synthetic VE significantly increased the relative length of small intestine in laying hens(P<0.05).Compared with the control group,protein-oxidized soybean meal significantly reduced the villus height in jejunum and the ratio of villus height to crypt depth in duodenum and jejunum(P<0.05),and the values of above indicators were recovered to the levels of control group after the addition of natural VE(P>0.05).What’s more,protein-oxidized soybean meal alsosignificantly increased the duodenual crypt depth of the laying hens(P<0.05),which was normalized by synthetic VE inclusion(P>0.05).Compared with the protein-oxidation group,the inclusion of synthetic VE significantly increased the contents of duodenum immunoglobulin G(IgG)and ileum immunoglobulin M(IgM)of laying hens(P<0.05).Compared with the control and protein-oxidized soybean meal groups,synthetic VE supplemention significantly increased the relative length of the small intestine and the secretory immunoglobulin(SIgA)concentration in the duodenum(P<0.05).Compared with the control group,protein-oxidized soybean meal significantly increased interleukin 1β(IL-1β)content in the duodenum and interleukin 6(IL-6),tumor necrosis factor a(TNF-α)and intercellular cell adhesion molecule 1(ICAM-1)levels in the ileum(P<0.05).The supplementation of synthetic VE significantly reduced(P<0.05)the level of IL-1β in the duodenum and IL-6 in the ileum,both synthetic and natural VE significantly decreased(P<0.05)the levels of TNF-α and ICAM-1 in the ileum,and synthetic VE inclusion significantly lowered(P<0.05)the IL-1β content in the ileum,when compared with the protein-oxidized soybean meal group,with the values of these parameters being similar to the control group(P>0.05).Moreover,compared with the control and protein-oxidized soybean meal groups,synthetic VE significantly reduced the IL-6,TNF-α and ICAM-1 contents in the duodenum(P<0.05).Both synthetic and natural VE significantly reduced mRNA expression levels of IL-1β and IL-6 in the duodenum and the jejunum of laying hens when in comparison with the control and protein-oxidized soybean meal groups(P<0.05).Trial Ⅲ aimed to study the effects of VE in alleviating antioxidant function of laying hens fed with protein-oxidized damage soybean meal.The experimental design was the same as the experment one.The results were presented as follows:compared with the control group,protein-oxidized soybean meal significantly increased the malondialdehyde(MDA)content in the serum,liver,jejunum mucosa and yolk(P<0.05),whereas significantly reduced(P<0.05)the serum glutathione peroxidase(GSH-Px)activity and superoxide anion radical scavenging ability,total superoxide dismutase(T-SOD)activity in ileum mucosal and yolk,as well as hydroxyl radical scavenging ability in the liver,jejunum and ileum mucosa of laying hens.The addition of synthetic and natural VE restored MDA content and superoxide anion free radical scavenging ability in the serum,T-SOD activity and hydroxyl free scavenging ability in the ileum mucosa,and hepatic hydroxy free scavenging ability to the levels of control group(P>0.05).Compared with the protein-oxidized soybean meal group,Synthetic VE inclusion significantly enhanced the activities of hepatic T-SOD and jejunum mucosal GSH-Px,where assignificantly decreased the jejunum mucosal MDA content(P<0.05),and natural VE supplementation significantly increased the superoxide anion radical scavenging ability of liver(P<0.05).Compared with the control and protein-oxidized soybean meal groups,the addition of synthetic VE significantly reduced the MDA concentration in the duodenum mucosa(P<0.05),and both synthetic and natural VE supplementation significantly lowered the MDA content in the liver of laying hens(P<0.05).