Studies on Microbial Community Diversity of Four Takifugu rubripes Culture Systems

In order to investigate the microbial community characteristics of Takifugu rubripes pond culture systems, 16S rRNA gene high-throughput sequencing technology was used in this study. The community structure and diversity of gut microorganisms, water microorganisms and sediment microorganisms in T. rubripes single culture system, the bi-species polyculture system of T. rubripes with Mercenaria mercenaria, the tri-species polyculture system of T. rubripes with Penaeus japonicus and M. mercenaria, and the traditional bi-species polyculture system of T. rubripes with Penaeus japonicus were compared. The results showed that Campilobacteria, Proteobacteria, Spirochaetota and Firmicutes are the dominant bacteria in the intestinal microbes of T. rubripes. Campylobacter may be the unique dominant bacteria in the gut of T. rubripes. Desulfobacterota, Bacteroidota, Firmicutes and Chloroflexi are the dominant bacteria in the sediment. Proteobacteria, Cyanobacteria, Bacteroides and Actinobacteriota are the dominant bacteria in the water. Although there was no significant difference in microbial α diversity in the gut of T. rubripes in different systems, the PCoA analysis showed that there were significant differences in microbial community structure among gut, sediment and water of T. rubripes in different culture systems. The similarity between gut microbes and environmental microbes each culture system was low, indicating that the intestinal microbial composition of T. rubripes may be less affected by environmental microorganisms. Redundancy analysis showed that the community structure and diversity of environmental microorganisms were affected by sediment and water environmental factors, respectively. Among them, salinity, ammonia nitrogen, nitrous nitrogen, nitrate nitrogen and total nitrogen were significantly correlated with the community structure of water flora (P<0.05) while nitrous nitrogen, nitrate nitrogen and total nitrogen were significantly correlated with the community structure of sediment flora (P<0.05).