牦牛发酵酸奶中耐久肠球菌的筛选鉴定和益生特性  

Identification of Enterococcus durans Isolated from Naturally Fermented Yak Milk and Its Probiotic Potentials

作　　者：黄坚[1] 童京京 岳华[1] 汤承[1] HUANG Jian;TONG Jingjing;YUE Hua;TANG Cheng(College of Life Science and Technology, Southwest Minzu University, Chengdu 610041, China)

机构地区：[1]西南民族大学生命科学与技术学院,四川成都610041

出　　处：《食品科学》2017年第12期43-49,共7页Food Science

基　　金：中央高校基本科研业务费专项(2015NZYQN32);"十二五"国家科技支撑计划项目(2012BAD13B06)

摘　　要：为从牦牛发酵酸奶中筛选出新的食源性益生菌株,通过培养分离、16S rRNA基因测序分析和生化实验鉴定出4株耐久肠球菌。这4株分离株与已报道的8株耐久肠球菌的同源性高达99.4%~99.9%,并且在系统发育树中单独聚为一支。其中耐久肠球菌SWUN5857的体外抗酸和抗胆盐能力最强,在体外可以有效抑制致病性大肠杆菌(抑菌圈直径(17.0±0.3)mm)和沙门氏菌(抑菌圈直径(18.0±0.2)mm)的生长,对常见的大多数抗生素都敏感,并且可以很好地与小鼠各段肠黏液产生黏附。短期喂服耐久肠球菌SWUN5857可以显著提高小鼠体质量(P<0.01),促进动物脾脏和胸腺的发育,同时还可提升动物体液和细胞免疫水平(P<0.01)以及肠道SIg A的表达水平(P<0.01)。综上所述,分离得到的耐久肠球菌SWUN5857能很好地适应胃肠环境压力,有效提高动物的生长性能和免疫功能,可以作为候选的益生性菌株。This study aimed to screen new probiotics from naturally fermented yak milk.We separated and identified fourEnterococcus durans strains by bacterial cultivation,gene sequence alignment and biochemical analysis.These four strainsshared99.4%–99.9%genetic homology by comparison of their16S rRNA sequences with those of eight other E.duransisolates previously reported and were clustered into a separate branch by phylogenetic analysis.Among these isolates,E.durans SWUN5857exhibited the most robust resistance to acidic and bile salts and could greatly adhere to intestinalmucus in different segments of the intestinal tract in Kunming mice,especially in lower intestines.Moreover,it inhibitedthe growth of pathogenic Escherichia coli((17.0±0.3)mm)and Salmonella((18.0±0.2)mm),and it was also sensitiveto common antibiotics in vitro.Mice gavaged with SWUN5857for a short term showed a significant body weight gain(P<0.01)and an increase in immune organ indexes.Besides,this treatment also significantly promoted the animal humoraland cellular immunity level(P<0.01)and enhanced the secretion of intestinal mucosa SIgA(P<0.01).In conclusion,E.durans SWUN5857can successfully adapt to the gastrointestinal condition and improve animal growth performance andimmunological function,being,therefore,a promising candidate probiotic.

关 键 词：牦牛酸奶 耐久肠球菌 分离鉴定 益生作用 

分 类 号：TS201.3[轻工技术与工程—食品科学] TS252.54[轻工技术与工程—食品科学与工程]