| The microbiota colonized in intestines are extremely important for the host healthy. It is important to study intestinal microflora and the relationship between microflora and host for theoretical and practical significance, which would improve the host healthy, prevent disease and promote clinical diagnosis.The butyrate in intestines arised from microbial fermentation, At present, the study about butyrate-producing bacterium gradually become focus in the intestinal nutrition field, Which would help us to explore intestinal unknown functional microorganisms and obtain a better understanding of the microbial ecology of butyrate-producing bacterium; on the other hand, the studies also provide theoretical support to regulate the formation of butyrate and the quantity.of butyrate-producing bacterium.1 Comparison of volatile fatty acid and microbiota in faeces between healthy and diarrhoeal pigletsThe aim of this section was to compare volatile fatty acid (VFA) concentration and microbiota in faeces between the health and diarrhoeal piglets. Fecal samples of healthy and diarrhoeal piglets were collected, and used for determination of VFA concentration and analysis of microbiota. Results showed that, as compared to healthy piglets, the concentration of acetate in feces of diarrhoeal piglets was tended to increase, while the concentration of total VFA (TVFA), propionate and butyrate tended to decrease (P>0.05). The ratio of acetate to TVFA in faeces of diarrhoeal piglets was higher significantly than that in healthy piglets (P<0.05), while the ratio of propionate to TVFA in faeces decreased significantly after diarrhea (P<0.05). DGGE anlysis of total bacterial community and Clostridium clusterⅣgroup showed no significant changes in both bacterial community were found in faeses of piglets after diarrhoea. Similarity analysis of DGGE profiles revealed that the faecal samples of diarrheal piglets gathered in a same cluster. Results of real-time PCR showed that as compared to healthy piglets, the 16S rRNA gene copies of total bacteria. Lactobacilli and Clostridium cluster IV group decreased significantly in faeses of piglets after Diarrhea(P<0.05), while there was no significant change in the 16S rRNA gene copies of E. coli.2 Isolation and selection of butyrate-producing bacterium from the faces of pigletTo investigate the diversity of butyrate-producing bacteria in pig intestinal tract, Hungate technique with modified YCFA and M2GSC media were used to isolate and select butyrate-producing bacteria from faces of piglets. Total 172 suspected bacterial colonies were isolated according to the discriminating colonial morphology. After 24 h incubation under 37℃, the concentration of butyrate in the incubation liquid of suspected bacterial colonies was determined by GC. Thirty-three butyrate-producing bacteria were obtained by the preliminary screening. The concentration of butyrate in their incubation liquid was between 2 and 8 mmol/L. After preservation and reactivation,11 butyrate-producing strains were finally obtained for the further study.3 Identification and classification of the butyrate-producing bacterium from the faces of pigletThis study was designed to identify and classify butyrate-producing bacteria isolated from pig intestinal tract by morphological, biochemical characteristics and molecular analyses, The results showed that:Strains LGM-B3 and LGM-B7 were obligate anaerobic and Gram-positive bacteria without spore, belonged to Clostridium subterminale. Sequencing of the 16S rRNA gene revealed that strains LGM-D3. LGM-D10 and LGM-12 belonged to the same genus, which were related to Clostridium tertium with the homology of 99%. Strains LGM-F18 and LGM-15a were obligate anaerobic and gram-negative bacteria and had a closest relative with Megasphaera elsdenii. Strains LGM-F14 and LGM-F26 were gram-positive and facultative anaerobic bacteria, which were identified to be related closely to Enterococcus and Streptococcus, respectively. Strains LGM-J1, LGM-J9, LGM-J13, LGM-J13-2 and LGM-J16 belonged to Clostridium perfringens, were gram-positive anaerobic bacteria. The results demonstrated that these butyrate-producing bacteria clustered in different branches of phylogenetic tree, which suggests that butyrate-producing bacteria in the intestine have high diversity. |
