| In our study, we want to study the effect of Enterococcus faecium culture on the Intestinal colonization, Plasma and intestinal fluid immunoglobulins (Ig), Blood test and Lymphoid cell subsets of peripheral blood. And study the effects of Enterococcus faecium on the production of cytokines in supernatants of Con A-stimulated splencytes. We also use artificial rumen simulation instrument to evaluate the effect of Enterococcus faecium on ruminal fermentation. Trial 1: In this experiment we study the tolerance of bovine bile, simulate gastric and small intestinal juice to assess whether the Enterococcus faecium can be used as probiotic. Meanwhile, fourty BALB/c mice were assigned to administrate Enterococcus faecium culture to investigate the effect of Enterococcus faecium on intestinal microbiota. The results showed that Enterococcus faecium retained viability and increased in number after exposure to bovine bile 60 min, exhibited a intrinsically tolerant to bovine bile. When exposure to simulated gastric juice 60 min , the strain retained 56.03% viability of initial count. And exposure to small intestinal juice 120min, the strain retained 92.16% viability of initial count. After mice received Enterococcus faecium culture, the number of enterobacteria in the fecal was significantly decreased in the whole trial. Fecal aerobic bacteria count on day 7 and 14 were higher in Enterococcus faecium-fed mice, but fecal aerobic bacteria count was similar in two group in day 21. Fecal lactobacilli in mice recived Enterococcus faecium culture mice had higher counts than the control during the administration period.Trial 2: This research investigated the effect of Enterococcus faecium culture on mice Blood test and lymphocyte subset in peripheral blood, Immunoglobulins in plasma and intestinal fluid, Cytokine production secreted by splenocytes. The results showed that the percentage of double positive (DP) cell and the concentration of MCHC were significantly higher in peripheral blood of mice received Enterococcus faecium culture. MCV were significant decreased in the Enterococcus faecium-fed mice. But compared to control group, the percentage ofγδT cell, NK cell, Th cell, Tc cell, T cell et al and WBC,RBC, LYM et al in peripheral blood weren't affect by Entercoccus faecium culture administration. Plasma IgG concentration were significantly higher in Enterococcus faecium-fed mice compared with controls. Intestinal IgA concentrations were also increased in mice received Enterococcus faecium culture, but the difference is not significant. Plasma IgA and IgM of the mice appeared to be unaffected by Enterococcus faecium culture administration. The data of cytokines production showed that the continuous administration of E. faecium did not influence the concentration of IL-2 in all the time points assayed (compared with the control, P>0.05) . The concentration of IL-4,IL-6 and IFN-γincreased progressively in the spleen cell of E. faecium-fed mouse and peaked on day 14 of the trial, at that time point significantly higher than the controls(P<0.05) .Afterwards, the concentration was decreased. By day 21 of the trial, IL-6 and IFN-γconcentration were lower than the controls(P<0.05).Trial 3: This experiment want to study the effect of Enterococcus faecium on ruminal fermentation. And evaluate whether Enterococcus faecium can be used as direct-fed microbe in ruminant according the result of this study. Experiment were used completely random trial design and the artificial rumen simulation instrument. The group which didn't supply Enterococcus faecium was control group, analysis the effect of supply 1.25×106 and 6.25×106mL-1 Enterococcus Faecium on rumen fluid pH value, microbial crude protein(MCP), NH3-N and the VFA concentration. Ruminal pH value and MCP were not significantly affected by supplementing Enterococcus Faecium(P>0.05).However,supplementation with Enterococcus Faecium can increase in ruminal NH3-N concentration(P<0.01). Compared with control group ,acetate and total VFA concentration in 1.25×106 mL-1 Enterococcus Faecium group were higher than the control group. However,the concentration of propionate and butyrate, and the ratio of acetate to propionate were not significantly affected by supplementation of Enterococcus Faecium(P>0.05). The results implicated that Enterococcus Faecium did not change the type of rumen fermentation. but appropriate dose of supplementation could improve rumen digestion of carbohydrate in feed.
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