珠江口野生棘线鲬胃肠道微生物多样性

【背景】野生棘线鲬(Grammoplites scaber)具有丰富的营养价值，但关于其胃肠道微生物方面的研究较少。【目的】研究棘线鲬胃肠道微生物群落特征，以揭示其潜在的益生菌和致病菌，为其健康生长的微生物群落调控提供依据。【方法】利用免培养和纯培养技术相结合的方式对来自珠江口的野生棘线鲬胃肠道样品进行了研究。【结果】通过对16S rRNA基因V3区高通量扩增测序，共得到456个操作分类单元(operational taxonomic units，OTU)。分析结果显示，在门水平上，棘线鲬胃肠道内的主要优势类群为变形菌门(Proteobacteria)和厚壁菌门(Firmicutes)。在属级水平上，梭菌属(Clostridium)在棘线鲬胃肠道样品中普遍存在，综合占比为57.11%。基于16S rRNA基因进行表型和功能预测的结果表明，棘线鲬胃肠道内有益菌和潜在致病菌同时存在且有功能相互制约的趋势。纯培养实验采用12种不同的培养基进行选择性分离，共获得纯培养菌株99株，归类于3个门(Proteobacteria、Firmicutes和Actinobacteria) 4个纲10个目10个科13个属，其中优势类群为变形菌门(占比50.51%)，实现纯培养最多的属级类群为嗜冷杆菌属(Psychrobacter)。【结论】揭示了野生棘线鲬胃肠道微环境微生物的物种组成与多样性，可以为硬骨鱼类核心肠道菌群的研究提供基础参考。此外，有益和有害菌群的揭示可为野生棘线鲬作为海洋食物资源利用的食品安全提供一定的借鉴，为发展海洋渔业养殖提供数据支撑。

Microbial diversity in gastrointestinal tract of wild Grammoplites scaber collected from the Pearl River Estuary

Background] Wild Grammoplites scaber is nutritious, but the microorganisms in its gastrointestinal tract (GI) are rarely studied. Objective] To study the microbial community in GI of G. scaber, reveal the potential probiotics and pathogens, and thus to provide a reference for the regulation of beneficial microbes. Methods] We collected the GI samples of G. scaber from the Pearl River Estuary and investigated them with the culture-independent method and pure culture method. Results] Through high-throughput sequencing of V3 regions of 16S rRNA genes, a total of 456 operational taxonomic units (OTUs) were identified. At the phylum level, Proteobacteria and Firmicutes dominated the microbes in the GI. At the genus level, Clostridium was prevalent in the samples, accounting for 57.11%. The 16S rRNA gene-based phenotypic and functional prediction suggested that the GI of G. scaber harbored both probiotics and pathogens, and they tended to restrict each other. A total of 99 strains were screened out with 12 different selective media, and they belong to 13 genera, 10 families, 10 orders, 4 classes, and 3 phyla (Proteobacteria, Firmicutes, and Actinobacteria). The dominant group was Proteobacteria (50.51%), and Psychrobacter was the predominant genus. Conclusion] This study reveals the microbial composition and diversity in the GI of wild G. scaber, laying a basis for the research on the core intestinal microflora of teleost. In addition, the probiotics and pathogens identified in this study can serve as a reference for the safety of food made with G. scaber and for the development of marine fishery.