青石斑鱼肠道菌群研究

Study on the intestinal microflora of Epinephelus awoara

以中国沿海重要经济鱼类青石斑为研究对象,分别以营养琼脂和脑心浸液琼脂培养基检测其肠道中总的好气和兼性厌氧菌及专性厌氧菌的数量,以TCBS(Thiosulfate Citrate Bile Salts Su-crose)、麦康凯、NAC(Nalidixic acid-cetri mide)、锰营养盐、TPY(Tryptone-phytone-yeast extract)和SL(Rogosa SL.)琼脂等6种选择性培养基对青石斑肠道菌群进行计数和选择性分离,并对分离的优势菌株进行16S rRNA基因同源性分析。结果表明,青石斑鱼肠道内好气及兼性厌氧菌的总量可达5.3×105CFU/g。在6种选择性培养基中TCBS培养基上生长的菌落数量最多,约占总好气菌及兼性厌氧菌的36%,优势菌与牙鲆弧菌(Vibrio olivaceussp.nov.)同源性最高;麦康凯琼脂平板中生长的菌落数量次之,约占总好气菌及兼性厌氧菌的24%,优势菌与阿氏肠杆菌(E.asburiae)同源性最高;而NAC和锰营养盐琼脂平板中生长的菌落数量较少,优势菌分别与假单胞菌属(Pseudomonassp.)和枯草芽孢杆菌(Bacillus subtilis)的同源性最高。厌氧菌的数量很少,约为总好气和兼性厌氧菌数量的1%,其中TPY培养基中生长的菌落数量约占总厌氧菌数量的53%,优势菌与拟杆菌(Bacteroidessp.)同源性最高;SL培养基中没有检测到细菌。

In this experiment, studies were conducted on the intestinal microflora of E. awoara, one of the commercially valuable fish in the coastal areas of China. Nutrient agar was used for cultivating the total intestinal aerobe and facultative anaerobe, while Brain Heart Infusion Agar was used for cultivating the total anaerobe. Another six kinds of selective medium, including TCBS, Macconkey, NAC, Manganese Nutrition, TPY and SL medium, were used for screening and isolating different intestinal microflora. The 16S rRNA gene homology of the predominant strains was analyzed. The results indicated that the total aerobe and facultative anaerobe in the intestinal tract of E. awoara reached 5. 3 × 10^5 CFU/g. The bacteria grown in TCBS medium was the most in quantity among the bacteria grown in the 6 kinds of selective medium, approximately accounting for 36 G of the total aerobe and facultative anaerobe, with the predominant bacteria having the highest homology with V. olivaceus sp. nov. The bacteria grown in the Macconkey medium was the next, approximately accounting for 24 G of the total aerobe and facultative anaerobe, with the predominant bacteria having the highest homology with E. asburiae. Whereas bacteria grown in NAC and Manganese Nutrition medium were much less, the predominant bacteria having the highest homology with Pseudomonas sp. and Bacillus subtilis, respectively. The anaerobe was very lower in quantity, only accounted for 1% Of the aerobe and facultative anaerobe in the intestinal tract. Among the anaerobe, the bac- teria grown in TPY agar occupied about 53 ~ of the total anaerobe, with the predominant bacteria having the highest homology with Bacteroides sp. No bacteria in the SL medium were detected.