青海湖裸鲤肠道中益生性乳酸菌的筛选

Screening of Probiotic LAB from G. przewalskii Intestinal

从青海湖裸鲤肠道中分离21株乳酸菌代表株,对其益生性进行研究。通过纸片扩散法、人工模拟胃肠道分析乳酸菌抗生素敏感性以及对胃肠道环境的耐受性。对筛选出来的优良乳酸菌进行胆盐耐受性、抑菌活性、高盐耐受性、温度生长范围的研究。结果表明:21株乳酸菌主要对万古霉素、庆大霉素、多粘菌素B、环丙沙星、青霉素G有抗性,抗性菌株分别达到20株(95.24%),18株(85.71%),20株(95.24%),20株(95.24%),17株(80.95%)。大多数乳酸菌对胃肠道环境的耐受性较差,7 h后活菌数最高的为qz1242,达到31.95%;其次为qz1209,存活率为18.52%;qz1215存活率为10%,qz1231存活率为9.27%。对这4株优良菌进一步检测显示:乳酸菌代表株在1%胆盐浓度下具有耐受性,并随着胆盐浓度的增加对乳酸菌的生长显示出抑制性。在质量分数为10%的盐条件下都生长良好,显示出耐盐性,其中qz1215在15%的高盐浓度下仍可以生长。qz1209、qz1215、qz1242在5~50℃温度范围内都生长良好,显示出较宽的温度生长范围。代表株发酵上清液对金黄色葡萄球菌、沙门氏菌等6种病原菌具有较强的抑制作用。本研究可为动物肠道附着益生性乳酸菌的开发与应用提供依据。

21 Representative strains of LAB were isolated from Gymnocyprisprzewalskii intestinal contents to analyze their probiotic. 21 strains of LAB were detected susceptibility in an agar diffusion technique to 10 kinds of commonly used antibiotics andartificial gastrointestinal tolerability testing, screening excellent strains were subject to simulation of tolerance to bile, high salt, antimicrobial activity, growth temperature range. All of LAB were resistant to vancomycin gentamicin, polymyxin B, ciprofloxacin, penicillin G. The resistance strains were reached 20（95.24%）, 18（85.71%）, 20（95.24%）, 20（95.24%）, 17（80.95%）, respectively. Most LAB resistance had some differences between speciesand some were multi-drug resistant strains. After 7 h artificial gastrointestinal tolerability testing, the results showed a low survival rate of lactic acid bacteria, the highest survival rate for qz1242, reached 31.95%, followed by qz1209, the survival rate was 18.52%, qz1215 survival rate was 10%, qz1231 survival rate was 9.27%. The results showed that LAB representative strains resistant to bile salt at a concentration of 1%, with the bile concentration increasing exhibit inhibitory. In10% of the mass fraction of salt were growing well, it showed salt tolerance, qz 1215 at 15% of the high salt concentration can still grow. They can growat 5-50 ℃ temperature range, which showed a wide growth temperature range. Fermentation supernatant of representative strains had a strong inhibitory effect to Staphylococcus aureus, salmonella and other six kinds of pathogens. This study may provide the basis for the development and application of animal gut probiotic lactic acid bacteria. It canprovide reference data for its application in the fermentation direction.