Effect Of Dietary Xylooligosaccharide Supplementation On Performance And Intestinal Barrier Of Laying Hens

Intestinal health of poultry is directly related to the immunity and health,the efficient absorption and discharge of nutrients.Aiming at the sensitivity of intestine to stress during peak laying period,this study firstly determined the appropriate level of xylooligosaccharide in laying hens'diets by observing the effects of different doses of xylooligosaccharide on laying hens'performance,intestinal morphology and intestinal mucosal immune index,and further discussed the problem of intestinal damage caused by polyunsaturated fatty acids.The effect of xylooligosaccharides on intestinal mucosal barrier of laying hens was to provide reference for improving intestinal health and application of xylooligosaccharides during peak laying periodExperiment 1.Effect of Dietary Different Levels Xylooligosaccharide on Performance and Intestinal Mucosal Barrier of Laying Hens.The objective of this study was to investigate the effects of different supplemental levels of xylooligosaccharide?XOS?on performance,egg quality,serum antioxidant indices and intestinal mucosal barrier of laying hens.Three hundred and sixty healthy 45-week-old Hy-Line laying hens with uniform body weight and egg production were randomly divided into five treatments containing 8replicates of 9 birds each.Layers in the control were fed a basal diet,and those in experimental groups were fed a basal diet with 100,200,400 and 800 mg/kg XOS,respectively.The feeding trial lasted for12 weeks followed a one-week adaptation phase.The results showed as follows:1)Dietary XOS supplementation had a quadratic effect on feed conversion during earlier?from 44 to 50 weeks?,later?from 51 to 56 weeks?and whole period?from 44 to 56 weeks?of the experiment?P<0.05?.Dietary XOS linearly decreased production during later period?P<0.05?,and linearly increased yolk color at end of 12 weeks of this experiment?P<0.05?.2)The activities of glutathione peroxidase?GSH-Px?in serum improved linearly?P<0.05?,while the Malondialdehyde?MDA?content showed a quadratic change with the XOS supplementation increasing?P<0.05?.3)Dietary XOS tended increased the villus height in ileum?0.05<P<0.10?,and significantly improved the villus height to crypt depth ratio?P<0.05?.The ileum mucosal secretory immunoglobulin A?sIgA?level was increased significantly with the XOS supplemented?P<0.05?,and showed a quadratic change with the supplementation increasing?P<0.05?.The results indicate that dietary XOS can improve intestinal morphology,regulate intestinal mucosal immune,maintain the function of intestinal mucosal barrier,and thus promoting the performance of laying hens.Based on the performance and intestinal mucosal immune,the optimal supplemental does of XOS is 350⁴50 mg/kg for laying hens in current study.Experiment 2.Effect of Oxidized Fish Oil and Xylooligosaccharide on Performance and Intestinal Mucosal Barrier of Laying HensThis experiment was conducted to investigate the effects of oxidized fish oil?OFO?and XOS on performance and intestinal mucosal barrier of laying hens.Three hundred and sixty healthy 45-week-old Hy-Line laying hens with uniform body weight and egg production were randomly divided into five treatments containing 8 replicates of 9 birds each.The groups fed the basal diets supplemented 2%soybean oil?SO group?,2%fish oil?FO group?,2%oxidized fish oil?OFO group?,2%oxidized fish oil+200 mg/kg XOS(OFO/XOS₂₀₀00 group)and 2%oxidized fish oil+400 mg/kg XOS(OFO/XOS₄₀₀00 group),respectively.The feeding trial lasted for 12 weeks followed a one-week adaptation phase.The results showed as follows:1)Compared with the FO group,OFO group significantly decreased production in later period of experiment?P<0.05?,and significantly increased the ratio of feed to egg in later and whole period?P<0.05?.Compared with the OFO group,OFO/XOS₂₀₀00 tended increased production in later period?0.05<P<0.10?,and significantly decreased the ratio of feed to egg?P<0.05?.The MDA levels of OFO group,OFO/XOS₂₀₀00 group and OFO/XOS₄₀₀00 group were significantly higher than those in SO group and FO group?P<0.05?.3)Compared with the SO group,FO group improved villus height to crypt depth ratio?V/C??P<0.05?.OFO/XOS₄₀₀00 group's villus height,V/C and the number of goblet cells were higher than others?P<0.05?.4)Compared with the FO group,OFO group significantly decreased sIgA level of ileum mucosal?P<0.05?.Compared with the OFO group,OFO/XOS₂₀₀00 group significantly increased ileum mucosal TNF-?content?P<0.05?,and tended increased IL-6 level?0.05<P<0.10?.OFO/XOS₄₀₀00 group's sIgA,IL-2,IL-6 and TNF-?levels of ileum mucosal were significantly higher than those in OFO group?P<0.05?.5)The OFO group's mRNA expression levels of claudin-1 and claudin-5 in ileum mucosal were reduced?P<0.05?.And compared with OFO group,OFO/XOS₄₀₀00 group significantly up-regulated expression of claudin-5 in ileum mucosal?P<0.05?.6)Compared with SO group,FO group and OFO/XOS₄₀₀00 group increased ACE and Chao 1 index?P<0.05?.Compared with SO group,the relative abundance of Firmicutes in FO group,OFO group and OFO/XOS₄₀₀00 group decreased.The relative abundance of Bacteroidetes in OFO group and OFO/XOS₄₀₀group was significantly higher than that in FO group.The relative abundance of Bacteroidetes in OFO group was the highest.And thus,the lowest abundance ratio of Firmicutes to Bacteroidetes was observed in OFO group.The results indicate that dietary oxidized fish oil reduces the performance of laying hens and impairs the intestinal mucosal barrier function,while the addition of XOS can alleviate the adverse effects of oxidized fish oil on performance and protect the intestinal mucosal barrier.In conclusion,dietary xylooligosaccharides can improve the intestinal mucosal barrier function and performance of laying hens.Based on the performance and intestinal mucosal immunity,the dosage of xylooligosaccharides in basic diet is recommended to be 350⁴50 mg/kg.It can also alleviate the intestinal mucosal barrier damage of laying hens by improving intestinal morphological structure,regulating intestinal mucosal immunity and intestinal microbial structure.