The Study Of Characteristics Of Enterococcus Faecalis From Pigs And It's Effects On Growth Performance And Immunity Of Piglets

The characteristics of Enterococcus faecalis isolated from healthy intestinal tract of piglets and its effects on growth performance and immunity of piglets were studied. The strain characteristics results showed as follows. The bacterium's survival rate was 86.1% and 91.3% when the E. faecalis sustained in artificial gastric juice 2 hours under pH 2.0 and pH 3.0, respectively, The viable count was 106cfu/mL when the strains cultured in 0.3% pigs bile salt medium of MRS 6 hours. The E. faecalis had temperature tolerance in the present study. The survival rate was 44.77% when the strain sustained in 65℃1 min, while the rate was 5% when 70℃50 sec. The result of high copper tolerance was different using two different methonds. the results were showed that E. faecalis could grow in different copper medium. When the copper content was 200ppm/L, the survival rate of filtration sterilization is higher than autoclave sterilization, the survival rate was 5.08% and 0.82% respectively. The E. faecalis could produce 625.26mg/L extracellular polysaccharide. The in vitro antibacterial test showed that the E. faecalis could inhibit pathogenic bacteria from swine and chicken. The susceptibility test showed that E. faecalis was sensitive to penicillin, ampicillin, norfloxacin, doxycycline, chloramphenicol, and Cefalotin, medium sensitive to gentamicin, streptomycin, ciprofloxacin, azithromycin bacitracin, tetracycline, and cefotaxime, and insensitive to co-trimoxazole, sulfamethoxa-zole tebuconazole, Polymyxa Su B, and rifampin. Fuethermore, a series of protective agents were filtered in this study, and a freeze-dried formula which suitable for E. faecalis was obtained.The effects of E. faecalis and other probiotics home-made in laboratory on weight gain and diarrhea rates of piglets were studied. The results showed that the weight gain of treatment piglets increased 17.64%, 14.31% and 6.04% (P <0.05) compared with the control group and diarrhea rate reduced 36.34%, 47.55 % and 47.87% when the E. faecalis and probiotics were given at 5d and 10d after birth. Adding E. faecalis and other probiotics in weaned piglet's diet, the average daily daily gain and feed efficiency was increased, the diarrhea rates were reduced, and the number of E. coli and Staphylococcus aureus in fecal was decreased, the content of Lactic acid bacteria was increased. Compared with the control group, the Serum IgG antibody levels was increased, the albumin and globulin ratio and the Serum urea were reduced, but no antibody synergy with PRV vaccine.