斜带石斑鱼消化道乳酸菌在模拟胃肠道环境中的存活  

Survival of lactic acid bacteria isolated from gut of Epinephelus coioides in mimic gastrointestinal environments

作　　者：孙云章[1,2] 杨红玲[1] 马如龙[1,3] 宋凯[1,2] 

机构地区：[1]集美大学水产学院省高校水产科学技术与食品安全重点实验室,福建厦门361021 [2]集美大学水产学院厦门市饲料检测与安全评价重点实验室,福建厦门361021 [3]南京农业大学消化道微生物实验室,江苏南京210095

出　　处：《中国水产科学》2010年第1期128-135,共8页Journal of Fishery Sciences of China

基　　金：国家自然科学基金项目(30600461);福建省高校水产科学技术与食品安全重点实验室基金项目(2009J102);集美大学科研基金项目(ZQ2006012)

摘　　要：从斜带石斑鱼(Epinephelus coioides)幼鱼消化道分离到3株乳酸菌,通过抑菌试验筛选出抑菌效果较好的2株菌(MM1和MM4),经生理生化鉴定结合16SrRNA基因测序分析,MM1菌株鉴定为乳酸乳球菌(Lactococcus lactis),MM4菌株鉴定为屎肠球菌(Enterococcus faecium)。进一步研究了MM1和MM4的体外生长特性,及其对不同pH值的人工胃液、含有不同浓度胆盐的人工肠液及高温的耐受能力。结果表明,MM1和MM4均在培养6h左右进入对数生长期。对人工胃液的耐受能力相似,pH4.0和3.0的人工胃液对2株菌存活的影响较小,而pH2.0的人工胃液对2株菌的影响较大,经2h处理后两者的存活数即下降到105CFU/mL,经4h处理后的存活数低于5.0×103CFU/mL。MM1和MM4对含不同浓度胆盐的人工肠液均具有较好的耐受能力,含中低浓度胆盐(0.1%～0.3%)的人工肠液对2株菌的存活影响很小,处理3h后2株菌的存活数均维持在107CFU/mL以上;高浓度胆盐(0.5%～0.7%)处理3h后2株菌的存活数明显下降,但活菌数仍维持在105CFU/mL以上。MM1和MM4具有一定的耐高温能力,60℃处理30min二者存活数在107CFU/mL以上;80℃处理30min二者存活数在106CFU/mL以上。结论认为,2株乳酸菌具有生长速度快、抑菌能力强、对胃肠道环境和高温耐受能力较强的特点,具有作为益生菌的应用潜力。Application of probiotics in aquaculture for primary disease control has become a promising research field. Lactic acid bacteria can inhibit the growth of pathogenic bacteria and have been used as probiotics to modulate composition of gut microbiota and maintain health of host. In this study, three strains of lactic acid bacteria were isolated from gut of juvenile Epinephelus coioides, among which two were selected for further study based on their pathogen inhibition activity. The two strains were identified as Lactococcus Lactis （MM1） and Enterococcus faecium （MM4）, respectively. Growth characteristics of the two strains and their tolerance to mimic gastrointestinal environments and high temperature were studied in vitro. The results showed that both strains propagated rapidly and entered logarithmic growth phase after 6 h incubation in MRS media. MM1 and MM4 showed similar tolerance to artificial gastric juice. Survival number of both strains were more than 106 CFU/mL after 2 h incubation and more than 10s CFU/mL after 4 h incubation at pH 3.0 or pH 4.0, which suggested that artificial gastric juice at pH 3 and pH 4 had slight effect on both strains. However, survival number of both strains were only 10^5 CFU/mL after 2 h incubation and less than 5.0 × 10^3 CFU/mL after 4 h incubation at pH 2.0. MM1 and MM4 exhibited excellent tolerance to artificial intestinal juice （containing different concentrations of bile salt and trypsin）. Survival number of both strains were more than 10^7 CFU/mL after 3 h incubation with artificial intestinal juice containing 0.1%-0.3% bile salt and maintained 10^5 CFU/mL after 3 h incubation with high concentration bile salt （0.5%-0.7%）. Furthermore, MM1 and MM4 exhibited good tolerance to high temperature. Survival number of both strains were more than 107 CFU/mL after 30 min treatment at 60 ℃ and maintained 106 CFU/mL after 30 min treatment at 80 ℃ . Therefore, MM1 and MM4 have the potential to be probiotics for their good performances on growth, pathogen inhibi

关 键 词：乳酸菌 人工胃液 人工肠液 高温 胆盐 细菌存活 

分 类 号：R378[医药卫生—病原生物学]