鳙鱼是我国的重要经济鱼类,在我国各大水系均有分布。由于集约化养殖和抗生素等化学药物的使用,原生态环境中的鳙鱼已较为稀少。本研究选定广州市从化区某天然池塘未经投喂的鳙鱼为研究对象,探究该环境中鳙鱼肠道菌群特征。通过三代16-S rRNA扩增子测序,发现该生境中鳙鱼肠道菌群以厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)为主。在属水平上则主要包括未命名菌属ZOR006、Clostridium_sensu_stricto_1、Romboutsia、Paeniclostridium、Methylocystis等；通过对鳙鱼肠道菌群的分析,发现鳙鱼肠道菌群具有Cetobacterium、Bacteroides、Lactobacillus和Bacillus等多类已报道具有益生功能的菌属,可见该环境中的鳙鱼肠道菌群存在一定丰度的有益菌属,有利于水产饲用益生菌的分离。为分离到水产饲用的鳙鱼源益生菌,通过产酶能力测定和体外抑菌实验对候选菌株进行筛选,分离出同时具有产酶和抑菌功能的三株潜在益生菌,YB6、YB42和YB56。通过对其生长特性、疏水性能、自聚集率、同病原菌副溶血弧菌ATCC17802的共凝聚率的测定,表征其生理特性；最后通过菌落形态观察及16-S rRNA序列分析,YB6、YB42和YB56的鉴定结果显示其分别为贝莱斯芽孢杆菌(Bacillus velezensis strain)、暹罗芽孢杆菌(Bacillus siamensis strain)和解淀粉酶芽孢杆菌(Bacillus amyloliquefaciens strain)。

Bighead carp is an important economic fish in China, which is distributed in all major river systems in China. Due to intensive farming and the use of antibiotics and other chemical drugs, bighead carp is rare in the original ecological environment. In this study, bighead carp in a natural pond in Conghua District of Guangzhou was selected as the research object to explore the intestinal microflora characteristics of bighead carp in this environment. By sequencing 16-S rRNA amplifiers of the third generation, Firmicutes and Proteobacteria dominated the intestinal flora of bighead carp in this habitat. At the genus level, the dominant genera are bacillus ZOR006, Clostridium_sensu_stricto_1, Romboutsia, Paeniclostridium. and Methylocystis. Through the analysis of bighead carp intestinal flora, it is found that bighead carp intestinal flora includes Cetobacterium, Bacteroides,Lactobacillus and Bacillus, which have been reported to have probiotic functions. It can be seen that there is a certain abundance of beneficial bacteria in the intestinal flora of bighead carp in this environment, which is conducive to the separation of aquatic probiotics. In order to isolate the probiotics of bighead carp for aquatic feeding, the candidate strains were screened by enzyme-producing ability test and bacteriostatic test in vitro, and three potential probiotics with enzyme-producing and bacteriostatic functions were isolated, named YB6, YB42 and YB56. The growth curve, hydrophobicity, self-aggregation rate, and coagglutination rate with Vibrio parahaemolyticus ATCC17802 were measured to characterize its physiological characteristics. Finally, by observing colony morphology and analyzing 16S rRNA sequence, the identification results of YB6, YB42 and YB56 showed that they were Bacillus velezensis strain, Bacillus Siamensis strain and Bacillus amyloliquefaciens strain, respectively.

广东省重点领域研发计划项目（2018B020205002）