| Intestinal barrier function is very important for health status of broilers. At present,interest in the use of probiotics for health maintenance and disease prevention or treatmenthas increased markedly. Lactobacillus, as one of probiotics, can improve intestinal health ofbroiler chickens. Adhesion and colonization of Lactobacillus to the intestinal mucosal surfaceare critical prerequisite for exerting beneficial effect to their host. Although many studies haveshown that Lactobacillus exert favorable effects on intestine of the host, the mechanism ofLactobacillus modulating barrier function of small intestine is still not entirely understood. Inthe present experiments, our objective is to select potential hightly adherent strains ofLactobacillus and investigate effects of the strain on intestinal barrier function of broiler, andgain further understanding of the mechanism by which Lactobacillus protect intestinalmucosal barrier. The results of the present experiments will also provide scientific evidencefor application of Lactobacillus in practice.Trial1. Effect of selected Lactobacillus strain with high adhesion on expression ofintestinal mucin-2in broiler chickenSix strains were used in the present study. strain with high adhesion was selected, theacid and bile salt tolerance of the strain was further evaluated. The results showed that Lfermentum1.2029showed good adhesive ability and was able to survive in low pHconditions and in the presence of bile salts. To study the mucin expression of the smallintestine epithelium of broilers after the strain was orally administrated. Twenty four1-d-oldArbor Acres broilers were blocked into2experimental treatments: control group andlactobacillus treatment group. Fresh prepared aliquots (500μL,108CFU) of L. fermentum1.2029were administered to the treatment group birds via orogastric inoculation. Accordingly,the control group birds were inoculated with the same volume of PBS. The results showedthat the strain significantly increased goblet cell density in the jejunum and did not affectgoblet cell density of other intestinal segments. The treatment group with administration oflactobacillus induce a3.89-fold and3.32-fold increase in MUC2mRNA level in the jejunum and in the ileum compared with the controls (P <0.05), respectively. In the duodenum, mucinmRNA expression tended to increase after lactobacillus treatment, although the increase wasnonsignificant. The study suggests that L. fermentum1.2029can protect intestinal mucus bystimulating Muc2expessionTrial2. Effect of Lactobacillus fermentum1.2029on intestinal mucosal immuneresponse in Necrotic Enteritis of broiler chickensTo investigate the anti-inflammatory properties of L.fermentum1.2029in NE of chickens.Two hundred and fouty1-day-old male Arbor Acres broilers were blocked into3experimentalgroups: normal group, NE model group and L. fermentum treatment group. L. fermentum1.2029(1.0mLd-1,108CFU mL-1) was orally administered daily to L. fermentum treatmentgroup during the course of the experiment. Accordingly, all uninfected normal chickens wereinoculated with the same volume of PBS. C. perfringens (0.5mL on d1and1.0mL on d14–21,108CFU mL-1) was administered to chickens in NE model group. At28d, samples werecollected for histological scoring and mRNA analysis. Gross NE lesion scores were alsoperformed. The results showed that L. fermentum1.2029reduced NE lesion severity inchickens. Histological scores revealed that the control group revealed intact mucosa.Intestinal specimens from C. perfringens challenge group exhibited strong inflammatorydamage, whereas in L. fermentum1.2029treatment group, these symptoms were attenuated.The results from real time-PCR analysis showed that C. perfringens increased mRNAexpression of TLR2and IFN-γ by two fold and three fold, respectively. L. fermentum1.2029treatment down-regulated the level of TLR2and IFN-γ (P <0.05). The expression of IL-10was decreased after C. perfringens infection, L. fermentum1.2029treatment up-regulated thelevel of IL-10(P <0.05). TLR4had no significantly changes among three groups. The resultsshowed that L. fermentum1.2029could regulate intestinal mucosal immune response andameliorate inflammation by changing expression of cytokine and TLR expression.Trial3. The effect of L. fermentum1.2029on intestinal epithelial restitution inNecrotic Enteritis of the broiler chickensTo investigate effect of L. fermentum1.2029on intestinal epithelial restitution inNecrotic Enteritis of the Broiler Chickens, Two hundred and fouty1-day-old maleArbor Acres broilers were blocked into3experimental groups: normal group, NE modelgroup and L. fermentum treatment group. L. fermentum1.2029(1.0mLd-1,108CFU mL-1) wasorally administered daily to L. fermentum treatment group during the course of the experiment.Accordingly, all uninfected normal chickens were inoculated with the same volume of PBS. C.perfringens (0.5mL on d1and1.0mL on d14–21,108CFU mL-1) was administered tochickens in NE model group. The results showed that L. fermentum1.2029promoted the migration of enterocytes along the crypt-villus axis in NE of chickens (P <0.05). Enzymaticactivity of sucrase and the expression of cdx1were increased by L. fermentum1.2029(P <0.05). L. fermentum1.2029treatment increased significantly the expression of EGFR in ileummucosa when compared with NE model and the EGF concentrations in plasma (P <0.05), butdid not affect ability of cell proliferation in crypt. In conclusion, L. fermentum1.2029couldaccelerate intestinal epithelial restitution in case of NE. The restitution process wasaccompanied with differentiation of the epithelium.Trial4. Effect of L. fermentum1.2029on expression of tight junction protein innecrotic enteritis of chickensTo investigate effect of Lactobacillus fermentum1.2029on expresion of tight junctionprotein in necrotic enteritis (NE) of chickens,2401-d-old Arbor Acres broiler chicks wererandomly separated into3groups: normal group, NE model group and L. fermentumtreatment group. At28d, chickens were killed, and ileal segments of24birds from eachexperimental group were collected for observation by electron microscope and mRNAanalysis by real-time PCR. The results showed L. fermentum1.2029improved damage ofmicrovilli in NE, L. fermentum1.2029increased level of claudin-1and occludin in NE ofchickens (P <0.05). The results indicated that L. fermentum1.2029had protective functionfor intestinal barrier... |
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