| Enterococcus faecium HDRsEF1and Bacillus subtilis HDRsbsl, which were screened in our lab and have good security and probiotic properties, were combined to be a probiotics agent, It was used to completely or partly replace antibiotics in piglet creep diets and conservation diets.The possibility and mechanism of completely or partly replacement of antibiotics in piglet diets were studyed by feeding the weaned piglets experiment. The effectiveness of probiotics on piglets production performance, serum biochemical parameters, specific antibody levels after vaccine immunization, phagocytosis of phagocytic cells, pH value of the gastrointestinal tract, immune organ index, mucosal SIgA value, intestinal mucosal morphology and intestinal flora were used as evaluated index, which can lay the theoretical and technical foundation for the probiotics as alternatives to antibiotics in weaned piglets.192Duroc-Landrace-Yorkshire piglets (28days old) were divided into three treatments:antibiotics control group (basal diet+20g/t colistin sulfate+50g/t kitasamycin, antibiotics group), partial substitution group of antibiotics (basal diet+100g/t Bacillus subtilis+300g/t Enterococcus faecium+20g/t colistin sulfate, partial substitution group), Completed substitution group of antibiotics (basal diet+100g/t Bacillus subtilis+300g/t Enterococcus faecium, probiotics group). The experiment period was35d. The results and conclusions display as following.Partial substitution and probiotics group were compared with the antibiotic group. Indicators of average daily gain, feed consumption and feed conversion were flat, and the differences were not significant (P>0.05), the rate of diarrhea reduced32.1%(P<0.05) and36.6%(P<0.05) respectively and each group had no mortality. The results showed that probiotics had the same growth-promoting effects with feed antibiotics, but also were obviously superior to feed antibiotics in reducing diarrhea rates.Trachea, duodenum and jejunum SIgA level of probiotics group were increased by108.5%(P<0.01),51.5%(P<0.05),22.5%(P>0.05) than the antibiotic group. IgA, IgG and IgM levels of partial substitution and probiotics group were significantly increased than the antibiotic group, hog cholera (HC) antibody levels were increased by53.42%(P<0.05) and32.73%(P<0.05), Foot-and-mouth disease (FMD) antibody levels were increased by22.23%(P<0.05) and39.21%(P<0.05), HC and FMD antibody positive rate of partial substitution, probiotics group and antibiotics group were100%. The results showed that probiotics significantly enhanced immunity and specific antibody levels of nomally used pig vaccines in weaned piglets.Compared with the antibiotic group, the blood biochemical indicators of partial substitution and probiotics group were not significant (P>0.05), but better than the antibiotic group in certain extent. The results showed that probiotics have no adverse effects on pig liver and heart function.The results of slaughter experiment for probiotics group and antibiotics group displayed that phagocytosis percentage of phagocytic cells of probiotics group was slightly higher than the antibiotic group, stomach, duodenum, jejunum, ileum, cecum, colon and rectum content pH of probiotics group were reduced by3.64%(P>0.05),5.76%(P>0.05),3.49%(P<0.05),8.48%(P<0.05),8.25%(P<0.05),9.87%(P<0.05) and5.50%(P<0.05) than the antibiotic group. Compared with antibiotics group, the spleen index and mandibular lymph node index of probiotics group increased by1.1%(P>0.05) and14.9%(P>0.05), villus length of duodenum, jejunum, ileum and colon were respectively increased by14.71%(P<0.05),12.73%(P<0.05),15.87%(P<0.05) and19.46%(P O.05), the ratio of villus length and crypt depth were respectively increased by12.79%(P<0.05),16.03%(P<0.05),13.20%(P<0.05) and16.83%(P<0.05). The results showed that probiotics were significantly better than feed antibiotics in improving intestinal acid environment, intestinal mucosal immunity and intestinal protection functions.The results of PCR-DGGE showed that in the pre-test period bands of fecal bacteria were few and colors were light in all groups. There were almost no differences in bacterial species among groups. In the late test, bands of fecal bacteria incresed and their colors were darker in all group, there were differences of bacterial species between groups. The test group and the control group developed into two distinct bacteria subpopulations. There were many similar bands between test groups, compared with control group, the test groups showed obvious difference. The results showed that probiotics had significant impact on the developments and establishments of intestinal microbial flora in weaned piglets. |
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