Effects Of Xylooligosaccharides On Growth Performance Slaughter Performance,Immune Function And Intestinal Function Of Broilers

XOS is a functional oligosaccharide to promote animal intestinal health,which belongs to a new prebiotic.Therefore,XOS can be used as an antibiotic substitute in the diet to promote animal growth.The purpose of this experiment was to study the effects of XOS on growth performance,slaughter performance,immune function and intestinal function of broilers.In the first experiment,the effect of XOS on growth performance,nutrient apparent metabolic rate and slaughter performance of broilers were studied.A total of 540 one-dayold Arbor Acres broilers were randomly divided 5 groups with 6 replicates in each group and 18 chickens in each replicate.The control group was fed with basic diet,the antibiotic group was added with 500 mg/kg oxytetracycline calcium in the basic diet,and the experimental group was added with 150 mg/kg XOS,300 mg/kg XOS and 450 mg/kg XOS in the basic diet for 42 days.The results showed as follows: 1)Compared with the control group,the body weight of broilers at 42 days of age,average daily gain at 1 to 42 days of age in the 150 mg/kg XOS group and 450 mg/kg XOS group was significantly increased(P < 0.05),There were no significant differences compared with antibiotic group(P > 0.05).Compared with the control group and antibics group,the average daily feed intake was significantly decreased at 22 to 42 days and 1 to 42 days of age among the xylooligosaccharide experimental groups(P < 0.05).Compared with the control group,the feed to gain ratio was significant decreased of 22 to 42 days and 1 to 42 days of age amang the xylooligosaccharide experimental groups(P < 0.05),there were no significant differences compared with the antibiotic group(P > 0.05).2)Compared with the control group,the apparent metabolic rate of calcium was significantly increased among the xylooligosaccharide experimental groups(P < 0.05),and there was no significant difference between the 150 mg/kg XOS group and the 450 mg/kg XOS group compared with the antibiotic group(P < 0.05).3)Compared with the control group,the abdominal fat percentage of broilers was significantly increased among the xylooligosaccharide experimental groups(P < 0.05),and there was no significant difference between the 150 mg/kg XOS group and the 450 mg/kg XOS group compared with the antibiotic group(P > 0.05).In the second experiment,the effect of XOS on immune function and intestinal physical barrier of broilers were studied.The results showed as follows:1)Compared with the control group,the indexes of spleen and bursa of fabricius was significantly increased among the xylooligosaccharide experimental groups(P < 0.05).2)Compared with the control group,the content of immunoglobulin A and the content of immunoglobulin G in 300 mg/kg XOS group were significantly increased(P < 0.05).3)Compared with the control group,supplementation of XOS had no significant effect on serum diamine oxidase content in broilers(P > 0.05).4)Compared with the control group,the crypt depth of duodenum in broilers was significantly decreased amang the xylooligosaccharide experimental groups(P < 0.05).5)Compared with the control group,the m RNA relative expression levels of Occludin in ileum was significantly increased amang the xylooligosaccharide experimental groups(P < 0.05),the m RNA relative expression levels of Claudin-1,ZO-1 in ileum was significantly increased of 300 mg/kg XOS group and the 450 mg/kg XOS group(P < 0.05).In the third experiment,the effect of combined supplementation of XOS on intestinal p H,and cecal microbial diversity of broilers were studied.The experimental animals and design were the same as the second experiment.The results showed as follows: 1)Compared with the control group,supplementation of XOS had no significant effect on intestinal p H values in broilers(P > 0.05).2)Compared with the control group,the addition of XOS impoves the Ace index,Chao1 index and Shannon index of cecal microbial in broilers.the addition of XOS significantly decreased the proportion of Firmicutes and Bacteroidetes,and increased the relative abundance of bacteria related to the production of short chain fatty acids.The correlation analysis between cecal microorganisms and intestinal physical barrier found that [Ruminococcus]_torques_Group was positively correlated with the up-regulation of the relative expression of occludin and Claudin-1 in ileum(P < 0.05),and Bacteroides was positively correlated with the increase of ileal villus height and the ratio of villus height to crypt depth(P < 0.05).In conclusion,the addition of XOS improved the production performance of broilers,improved the apparent metabolic rate of nutrients.the addition of XOS has the potential to replace antibiotics,and improved the slaughter performance of broilers.Supplementation of XOS enhanced immune function,improved gut morphology,increased ileal tight junction protein m RNA expression,and enhanced the barrier function of the broiler gut. Supplementation of XOS increases the diversity and richness of intestinal species,increases the number of beneficial bacteria,regulates the balance of intestinal flora,and promotes intestinal health.Under the experimental conditions,the suitable additive amount of XOS in broiler diet is 150 mg/kg.