猪源乳酸菌的筛选、体外益生效果评价及对小鼠肠道菌群的影响

Isolation and Probiotic Assessment of Lactic Acid Bacteria Strains from Piglets and It′s in vivo Effects on Intestinal Microbial Population of Mice

试验旨在筛选具有体外益生活性的乳酸菌株,并探讨其对小鼠肠道菌群的影响。试验从健康仔猪粪便中分离得到6株具有溶钙能力和对肠道致病菌有较强抑制性能的细菌,分别命名为R1-R6。经体外益生效果评价表明,在pH为3和4的条件下,菌株R1的菌数均显著高于其他菌株（P〈0.05）,并可耐受浓度为0.3%的胆盐条件。细胞黏附试验表明,菌株R1的黏附率显著高于其他5株乳酸菌株（P〈0.05）;乳酸菌R1对大肠杆菌、金黄色葡萄球菌、沙门氏菌和藤黄微球菌这4种指示菌的抑菌能力均要优于其余的5株细菌。菌株R1经16S rRNA基因序列分析鉴定为植物乳杆菌（Lactobacillus plantarum）。经小鼠体内评价研究表明,通过灌喂小鼠乳酸菌R1可提高小鼠肠道内乳酸杆菌的数量（P〈0.05）,同时显著降低其肠道内肠杆菌数量（P〈0.05）。结果表明,所筛选的乳酸菌R1具有益生菌特性,具有较好的开发应用前景。

The experiment aimed to isolate new lactic acid bacteria with putative probiotic potential from health piglet feces and to investigate their effects on the intestinal flora in mice. Six strains that showed the ability to dissolve calcium in medium and inhibition of enteric pathogens were selected and named R1, R2, R3, R4, R5 and R6. For the in vitro probiotic properties, stain R1 had a higher （P〈0.05） number than other bacteria at pH 3 and 4 and also showed a better （P〈0.05） tolerance to 0.3% of bile salt. R1 also had a stronger （P〈0.05） adhesion to mucin than the other five lactic acid bacteria. Meanwhile, stain R1 showed the best antimicrobial activity towards intestinal pathogens, including Escherichia coli, Staphylococcus aureus, Micrococcus luteus, Salmonella enterica. R1 was identified as Lactobacillus plantarum by 16S rRNA gene sequence analysis. In vivo studies showed that mice fed with R1 had an increased （P〈0.05） number of intestinal lactobacilli as well as a lower （P〈0.05） number of E. call in their gut. The study indicated that the lactic acid bacteria RI is a good candidate for its application as novel probiotic strain in the animal feed industry.