Effects Of Mannan Oligosaccharides On Intestinal Barrier And Intestinal Absorption In Broilers

As a green feed additive,MOS not only improves the intestinal micro-ecological environment,enhances digestion and absorption,strengthens the immunity of animals,but also promotes the growth and development of animals.Only a healthy and complete intestinal barrier can ensure the efficient digestion and absorption of nutrients in the intestine.At present,most of the studies on MOS in broilers at home and abroad focus on production performance,intestinal flora and intestinal morphology as one of the barriers in efficiency studies,while less research has been conducted on the comprehensive intestinal barrier and intestinal nutrient absorption in broilers.In this experiment,the effect of MOS on intestinal barrier and intestinal nutrient absorption was investigated in white feather broiler chickens as the research object.In this trial,42 1 day old white feather broilers were reared to 21 days of age and randomly divided into 7 groups based on similar body weight and 50/50 male and female:blank control group,model control group,MOS preventive low,medium and high dose group and health group,and ciprofloxacin lactate health group,with 6 replicates in each group for 18 days.Broiler chickens were started at 22 days of age and the blank control group was left untreated.The MOS preventive low,medium and high groups were fed 0.05g/L,0.1 g/L and 0.15 g/L of MOS solution for 7 days,and on the 8th day broiler chickens were injected with 8.37×10~9CFU/m L of E.coli solution 0.2 m L in the breast muscle,and the corresponding concentration of MOS solution continued to be given to each group respectively.The model control group,MOS health group and ciprofloxacin lactate health group were given 8.37×10~9CFU/m L of E.coli bacterium solution 0.2 m L by intramuscular injection on the 8th day of the trial,the model control group was given drinking water,the MOS health group was given 0.05 g/L MOS solution to drink freely,and the ciprofloxacin lactate health group was given 60 mg/L ciprofloxacin lactate to white broilers to drink freely.Blood was collected from all broilers on the 19th day of the experiment for the determination of serum biochemical parameters;all sections of the small intestine were taken for the determination of organ indices and paraffin sections were made to observe the morphological structure;intestinal tissues were collected for the detection of the expression of key genes of intestinal barrier and intestinal transporter by RT-q PCR,and the protein expression of the key factor NF-κB in the ileum by Western Blot.The results were as follows:1.Effect of MOS on the intestinal barrier of broiler chickens:compared with the blank control group,the body weight,duodenal index and ileal weight of broiler chickens in the model control group were significantly lower(P<0.05),the epithelial cells of the intestinal mucosa of duodenum and jejunum were shed,the lamina propria was exposed,more intestinal villi of ileum were fused with each other,the arrangement of glands was disordered,and Cldn2 was significantly higher(P<0.05);among them,Cldn1,Zo-1,Zo-2 and Tff2 of broiler chickens in the MOS prevention The broiler duodenum Cldn1,Zo-1,Zo-2 and Tff2were significantly higher(P<0.01),Avbd1,Avbd2 and Tgf-β1 were significantly higher(P<0.05),jejunal mucosa Muc5 was significantly higher(P<0.05),ileal Cldn1 was significantly higher(P<0.05),Tlr4 was significantly lower(P<0.01),and TNF-αwas significantly lower(P<0.05).Compared with the model control group,the broiler chickens in the MOS prophylaxis medium dose group had significantly higher body weight(P<0.05),neatly arranged mucosal epithelial cells in all intestinal segments,more villi folds,densely arranged glands,significantly lower Cldn2 in all three intestinal segments(P<0.05),duodenal matter Cldn1,Zo-1,Avbd1,Avbd2,jejunal Muc5,Ocln.Cldn1,Muc2,and Muc5 were significantly higher(P<0.05),duodenal Tff2 was highly significant(P<0.01),and p-NF-κB protein expression was highly significant lower(P<0.01).2.Effect of MOS on intestinal absorption in broilers:compared with the blank control group,ileal Glut2 was significantly lower(P<0.05)and Fabp6 was highly significantly lower(P<0.01)in the model control group;serum CHE,GLU and HDL-c were significantly increased(P<0.05),duodenal Fabp2 was significantly increased(P<0.05),Smct1 was highly significantly increased(P<0.01)and Y~+lat1 was significantly increased(P<0.05).Compared to the model control group,duodenal Smct1 was extremely significantly increased(P<0.01)and ileal Y~+lat1 was significantly increased(P<0.05)in the MOS prophylaxis mid-dose group.In summary,the prophylactic addition of medium dose MOS(0.1 g/L mannan-ol igosaccharide solution at 22 days of age)to drinking water can increase broiler body weight,ileal weight,increase the expression of physical,chemical and immune barri ers in the broiler intestine,reduce the expression of TLR receptors and inflammatory factors in various intestinal segments,increase the expression of anti-inflammatory fa ctors,alleviate E.coli-induced intestinal barrier damage in broilers,enhance the expre ssion of amino acids and fatty acid transport carriers,promote nutrient absorption and enhance broiler growth performance.