一株健康仔猪肠道乳酸菌的筛选鉴定与饲喂安全性的研究

摘要

A strain of lactic acid bacterium was screened from the intestinal tract of a healthy piglet.It’s i⁃dentification was based on bacterial culture,physiological and biochemical tests and 16S rDNA sequence analy⁃sis.Its potential probiotic feature was evaluated by its growth curve in MRS and its functional properties,inclu⁃ding antagonistic activity against pathogenic bacteria,survival form gastrointestinal tract conditions ( acidity and bile),antibiotic susceptibility and safety in chicken feeding.A strain WLEF-01 was identified as Enterococcus faecium.It exhibited rapid growth in MRS at 37℃ and entered the logarithmic phase after incubation 0.5 h.The generation time of WLEF-01 was 20 min and it reached 1.5×1011cfu/ mL in the stationary phase.The strain se⁃creted acid to the medium making pH 6.8 to 4.5 and showed better resistance to 1% bile salted and lower pH4.WLEF-01 revealed antagonism against pathogenic E.Coli and S.aureus to some degree.Fed to chicken from 0to 12 weeks,WLEF-01 2×107cfu/ g had no bad effects,which suggested that the strain is safe.From the resultsobtained,it can be concluded that WLEF-01 isolated from piglet intestinal tract is a potential probiotic strainfor feeding additive.%从健康仔猪的肠道中分离筛选到一株乳酸菌，经生理生化测定和16s rDNA基因序列同源性分析，该菌株为屎肠球菌，命名为WLEF－01。该菌株在MRS培养基37℃下培养，延滞期约0．5 h，对数生长期的代时为20 min，稳定期阶段的浓度可达1．5×1011cfu／mL。 WLEF－01的产酸能力较强，可使培养基pH从6．8降至4．5，并可耐受1％的猪胆盐作用2 h，在pH4以上酸性环境有耐受能力，并具有拮抗大肠杆菌和金黄色葡萄球菌生长的作用。在饲料中按2×107cfu／g浓度添加，饲喂泰和乌骨鸡12周龄，安全性好，有一定的益生功能。结果表明，屎肠球菌WLEF－01菌株具有作为益生菌饲料添加剂的开发应用潜力。