一株羊源弯曲乳杆菌的分离及安全性评价

Isolation and Safety Evaluation of a Sheep-Derived Lactobacillus curvatus

本试验旨在评估一株分离得到的羊源弯曲乳杆菌的潜在益生特性和安全性。采集新鲜健康绵羊粪便样品共13份,用于乳酸菌的分离筛选,再进行小鼠致病性试验,以确定分离菌的安全性。结果表明:1)初分离得到55株乳酸菌(编号:Y1~Y55)。2)分离菌Y15可耐受pH=3和1.0%胆盐,对青霉素G、头孢噻肟、氨苄西林、克林霉素和四环素敏感,对金黄色葡萄球菌和大肠杆菌抑制活性较好,无溶血活性。3)结合生化特性和测序结果将其命名为弯曲乳杆菌Y15。4)弯曲乳杆菌Y15在37℃下迅速生长至16 h达稳定期且具有良好的产酸能力。5)灌胃弯曲乳杆菌Y15对小鼠体征、分泌物、排泄物、体增重、采食量、体腔脏器和血液学参数均无显著影响(P>0.05),可显著增加结肠组织中杯状细胞数量(P<0.05),显著降低肝脏指数(P<0.05),显著升高血清总蛋白含量(P<0.05);小鼠腹腔注射试验中,2组小鼠体重无显著差异(P>0.05),体内脏器无明显眼观病理变化。综上可知,羊源弯曲乳杆菌Y15具有良好的益生特性,无急性毒性作用,通过了小鼠体内安全性试验。

This study was to evaluate the potential probiotic properties and safety of a sheep-derived Lactobacillus curvatus.Thirteen sheep fecal samples were collected for the isolation of lactic acid bacteria.Then,the pathogenicity test in mice was carried out,mice were then examined to determine the safety of isolated bacteria.The results showed as follows:1)fifty-five lactic acid bacterial strains(number:Y1 to Y55)were isolated.2)The isolated bacterium Y15,tolerated pH=3 and 1.0%bile salt,was susceptible to penicillin G,cefotaxime,ampicillin,clindamycin and tetracycline;and it showed the ability to inhibit Staphylococcus aureus and Escherichia coli without any detectable hemolytic activity.3)Based on biochemical properties and sequencing results,the Y15 was named Lactobacillus curvatus Y15.4)Lactobacillus curvatus Y15 grew quickly at 37℃to reach a level of stable good acid-producing level in 16 h.5)Lactobacillus curvatus Y15 via gavage had no significant effects on the body signs,secretions,excretions,body weight gain,feed intake,body cavity organs and hematological parameters of mice(P>0.05),could significantly increase the number of colonic goblet cells in colon tissues(P<0.05),significantly reduced the liver index(P<0.05),and significantly increased the serum total protein content(P<0.05).In addition,intraperitoneal injection of Lactobacillus curvatus Y15 into mice did not result in any significant changes of body weight(P>0.05),and no obvious pathological changes in internal organs.In conclusion,Lactobacillus curvatus Y15 isolated from sheep has good probiotic properties,and it do not induce any acute toxicity that passed the in vivo safety test in mice.