草鱼肠道黏膜厌氧细菌的分离与鉴定

ISOLATION AND IDENTIFICATION OF ANAEROBES IN THE INTESTINAL MUCOSA OF GRASS CARP CTENOPHARYNGODON IDELLUS

  • 摘要: 研究以草鱼(Ctenopharyngodon idellus)为实验对象, 运用厌氧培养的方法, 研究了饥饿状态下草鱼肠道黏膜固有微生物的类群及其在不同肠段的分布。实验结果显示草鱼前肠、中肠与后肠中细菌的数量分别是3.17×103、1.63×104和1.79×107 cfu/g。研究共分离到274株单菌落, 经16S rRNA鉴定, 分别属于拟杆菌属(Bacteroides spp.)、鲸杆菌属(Cetobacterium spp.)、梭形杆菌属(Fusobacterium spp.)、气单胞菌属(Aeromonas spp.)、希瓦氏菌属(Shewanella spp.)、芽孢杆菌属(Bacillus spp.)、泛菌属(Pantoea spp.)和柠檬酸杆菌属(Citrobacter spp.)8个种类, 其中专性厌氧细菌的数量占9.1%, 兼性厌氧细菌的数量占90.9%。进一步分析发现, 前肠中只分离到兼性厌氧细菌, 中肠与后肠专性厌氧细菌和兼性厌氧细菌都有分布。专性厌氧细菌Bacteroides paurosaccharolyticusBacteroides luti在中肠与后肠都有分布, 而Cetobacterium someraeFusobacterium ulcerans只在后肠有发现。兼性厌氧细菌是草鱼肠道黏膜的优势菌群, 其中嗜水气单胞菌Aeromonas hydrophila占73.7%。草鱼肠道不同部位固有厌氧微生物组成存在差异, 细菌数量也明显不同, 后肠中具有更高的细菌丰度和多样性。

     

    Abstract: The bacteria community in the gastrointestinal tract of fish has been the subject of numerous studies. However, most of those researches have focused on the molecular ecology of intestinal microbiota. Few studies pay attention to the bacterial culture, especially to the culture of the anaerobic intestinal bacteria, which leads to poor description in anaerobic autochthonous bacteria of gut. In this study, we investigated the autochthonous microflora of intestinal mucosa in grass carp (Ctenopharyngodon idellus) with the culture dependent method. The bacterial numbers in foregut, midgut and hindgut of the fish were 3.17×104, 1.63×105 and 1.79×108 cfu/g, respectively. A total of 274 bacterial isolations were sequenced and identified as genus Bacteroides, Cetobacterium, Fusobacterium, Aeromonas, Shewanella, Bacilluss, Pantoea and Citrobacter. 9.1% of which were obligate anaerobic bacteria and the others were facultative bacteria. The anaerobic bacteria, Bacteroides paurosaccharolyticus and Bacteroides. Eggerthii, were only found in midgut and hindgut, while Cetobacterium somerae and Fusobacterium varium were only found in hindgut. The facultative bacteria existed in the whole gut, among which Aeromonas hydrophila was dominant. Our results suggest that species and quantities of intestinal bacterial vary with the segments of C. idellus, and hindgut presents higher bacterial abundance and diversity.

     

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