Diversity of gastrointestinal tract microbes in wild Grammoplites scaber collected from the Pearl River Estuary

Grammoplites scaber is a source of highly nutritious marine food. However, studies on microorganisms in their gastrointestinal tract environments are very rare. To discovery the composition and diversity of microbes in gastrointestinal tract environments of wild G. scaber, we collected the intestinal samples from the Pearl River Estuary and studied them based on cultural and uncultural methods. After the amplification, sequencing, and analysis of the V3 regions of bacterial 16S rRNA genes from experimental sample, a total of 456 OTUs were obtained. Results of similar analysis revealed that Proteobacteria and Firmicutes were the most predominant groups at the phylum level and Clostridium was the prevalent genus in their gut environments with accounting for 57.11%. Results of phenotypic and functional prediction based on 16S rRNA gene showed that both beneficial bacteria and potential pathogenic bacteria existed in their gastrointestinal tract environments, and they tended to restrict each other at the ecological function level. This study revealed at firstly the microbial composition and diversity in the gut microenvironment of wild G. scaber , and also provided a basic reference for further study on the core intestinal microflora of teleost. In addition, the discovery of beneficial and harmful bacteria can provide certain reference for the food safety treatment of G. scaber as marine food resources, and provide scientific data support for the development of marine aquaculture industry.

糙皮棘鲬（Grammoplites scaber）是一种营养价值极高的海洋食用生物。然而，针对其胃肠道环境中微生物的相关研究却极为匮乏。为探明野生糙皮棘鲬胃肠道环境中的微生物组成与多样性，本研究从珠江口采集其肠道样本，并结合培养法与非培养法开展相关研究。通过对实验样本中细菌16S rRNA基因的V3可变区进行扩增、测序及分析，共获得456个操作分类单元（Operational Taxonomic Units，OTUs）。相似性分析结果显示，在门分类水平上，变形菌门（Proteobacteria）与厚壁菌门（Firmicutes）为优势菌群；梭菌属（Clostridium）则为肠道环境中的主要菌属，其相对丰度占比达57.11%。基于16S rRNA基因的表型与功能预测结果表明，其胃肠道环境中同时存在有益菌与潜在致病菌，二者在生态功能层面呈现相互制约的关系。本研究首次揭示了野生糙皮棘鲬肠道微环境中的微生物组成与多样性，为进一步研究硬骨鱼类核心肠道菌群提供了基础参考。此外，有益菌与有害菌的发现可为糙皮棘鲬作为海洋食用资源的食品安全处理提供一定参考，并为海水养殖业的发展提供科学数据支撑。