鳙鱼肠道菌群多样性及潜在益生菌的分离鉴定

该研究利用三代16S rRNA扩增子测序技术分析天然池塘生境鳙鱼肠道菌群特征，并从中分离潜在益生菌。该生境鳙鱼肠道菌群以厚壁菌门（Firmicutes，10.28%）和变形菌门（Proteobacteria，21.47%）为主。在属水平上，以未命名菌属ZOR006（21.63%）、严格梭菌属（Clostridium_sensu_stricto_1，10.84%）、罗姆布茨菌属（Romboutsia，10.34%）、类梭菌属（Paeniclostridium，9.63%）、甲基孢囊菌属（Methylocystis，8.74%）为主。为分离到既有利于营养物质的吸收又能抑制病原微生物的鳙鱼源芽孢杆菌（Bacillus），对从该生境鳙鱼肠道中分离的菌株进行产酶、抑菌等功能相关益生特性试验。试验共分离出3株细菌，YB6、YB42和YB56，通过菌落形态观察及16S rRNA序列分析，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）。试验结果表明，3株菌均具有良好的产胞外蛋白酶、淀粉酶、纤维素酶及抑制病原菌的能力，可以作为促消化和病原拮抗益生菌做进一步的研究。

Diversity of Gut Microbiota in Bighead Carp and the Isolation and Identification of Potential Probiotics

Using third-generation 16S rRNA amplicon sequencing, characteristics of the gut microbiota of bighead carp in natural pond habitats was analyzed and potential probiotics were isolated from the microbiota. The gut microbiota of bighead carp in natural ponds is dominated by Firmicutes (10.28%) and Proteobacteria (21.47%) at the phylum level. At the genus level, unnamed genera ZOR006 (21.63%), Clostridium_sensu_stricto_1 (10.84%), Romboutsia (10.34%), Paeniclostridium (9.63%), and Methylocystis (8.74%) were dominant. To isolate Bacillus from bighead carp, which is beneficial to the absorption of nutrients and inhibition of pathogenic microorganisms, the probiotic properties of strains isolated from the gut of bighead carps in natural ponds were tested for enzyme production and antibacterial functions. Three strains of bacteria, namely YB6, YB42, and YB56, were isolated in the experiment. Through colony morphology observations and 16S rRNA sequence analysis, these strains were identified as Bacillus velezensis, Bacillus siamens, and Bacillus amyloliquefaciens, respectively. These three strains exhibited excellent ability to produce extracellular protease, amylase, and cellulase and inhibit pathogenic bacteria; therefore, they may be used as probiotics to promote digestion and antagonize pathogens in further research.