Effect Of Probiotic L. Plantarum P-8on Gut Microbiota,Intestinal Immunity And Growth Performance Of Broiler Chickens

In this study, a probiotic strain, named L. plantarum P-8and was originally screened from koumiss, was fed to cobb500broiler chickens through drinking water. Its effects were compared with the experimental group fed with antibiotics. There major beneficial effects of L. plantarum P-8versus antibiotics were analyzed: intestinal bacteria, intestinal immunity function and animal performance. The objective was find the interaction between the gut microbiota with intestinal functions, as well as animal growth performance. The final aim of this study, was to define the mechanism of action of this probiotic microbe in broiler chickens gut, specifically the regulation of intestinal microbiota. The basal diet was mainly composed of corn and soybean. In the experiment, a total of270newly hatched cobb500broiler chickens were randomly divided into3treatments. Group1was the control group that was not given antibiotic in their diet (Control G), Group2was the antibiotic-treated group that contained chlortetracycline and salinomycin in diet (Antibiotic G). Group3was the probiotic group that L. plantarum P-8was added in their drinking water (2.0×106cfu/mL, LP-8G). The trial period was42days.Firstly, by using454pyrosequecing technology, the differences in intestinal microflora between probiotic and antibiotic groups was compared. The results showed that Antibiotic and LP-8G fecal samples were largely segregated. Secondly, using RT-qPCR method, the differences of intestinal dominant genus、Lactobacillus species and Bidobacterium species between the three groups were compared. The results showed that ingestion of LP-8could significantly increase the overall intestinal bacteria、Lactobacillus and Bifidobacterium genera in of broiler chickens of7、28、42d of age (P<0.01), as well as Fusobacterium of broiler chickens of28and42d of age (P<0.05), while significantly reduced Escherichia coli of broiler chickens of7、28、42d of age (P<0.01). In contrast, antibiotic treatment could significantly reduce intestinal Atopobium genus of28、42d old broiler chickens (P<0.01). Spleens、thymus and fabricius were sampled and processed to calculate the index of immune organ at day42of experiment. The contents of IgG in serum and SIgA in intestine mucous were measured by ELISA. The number of CD3+and IgA+of the small intestine mucous、Peyer’s and cecal tonsil were measured by immunohistochemistry. The percentage of CD3+、CD4+、CD8+T-lymphocyte subclass of spleen、intestinal epithelium、lamina propria and cecal tonsil were measured by flow cytometry. The gene expressive of intestinal cytokines was studied by relative quantification2-△CT in14、42d old broiler chickens. The results showed that the thymus, splenic and fabricius indices of42d old broiler chickens in LP-8G significantly increased (P<0.05). Moreover, the intake of L. plantarum P-8significantly increased blood IgG and SIgA of intestinal mucosa of14..42d old broiler chickens (P<0.05). In addition, the intake of L. plantarum P-8significantly increased the number of CD3+and IgA+of intestinal mucosa、cecal tonsils and Peyer’s IgA+(P<0.01). The intake of antibiotic significantly reduced the number of intestinal mucosal IgA+、Peyer’s CD3+and IgA+、cecal tonsils CD3+(P<0.01) in42d old broiler chickens. Intake of L. plantarum P-8could significantly improve the percentage of CD4+、CD8+、CD3+in intestinal mucosa、lamina propria、cecal tosil of14d old broiler chickens and the percentage of CD4+and CD4+/CD8+ratio in intestinal mucosa、lamina propria, the percentage of CD3+in cecal tosil of42d old broiler chickens. However, intake of antibiotic could significantly reduce the percentage of CD4+and CD3+of lamina propria, the percentage of CD3+of cecal tosil in42d old broiler chickens (P<0.01). The intake of L. plantarum P-8could significantly increase the gene expressive of the gut Bu-1、IL-12(P<0.05). Intake of antibiotic could significantly reduce the gene expression of IL-2、IL-4and IL-10in the gut of the42d old broiler chickens (P<0.05).The results of growth performance showed that ADG of22-42d old broiler chickens of LP-8G was significantly higher than the control G (P<0.05). ADG was significantly higher in antibiotic G than in the control G during1～21%、22～42days, and during the whole period (P<0.05).General conclusions can be drawn based on the above results:the probiotic L. plantarum P-8could survive in the host gut, improve the intestinal microbiota structure, reduce the adhesion and colonization of harmful bacteria, promote the growth of beneficial bacteria, and enhance intestinal defense function. L. plantarum P-8could regulate humoral and cellular immunity in the gut-associated lymphoid tissues in favor of the immune function and status of the host. L. plantarum P-8could significantly improve the growth performance during the late growth period of broiler chickens production.