Bacterial community in Sinonovacula constricta intestine and its relationship with culture environment

Although the importance of intestinal microbes to aquaculture animals has been recognized, the intestinal bacteria of Sinonovacula constricta and its culture environment are rarely studied. In this study, high-throughput sequencing was used to explore the intestinal bacterial communities of pond water, sediment, and S. constricta intestine. Significance analysis and principal coordinates analysis (PCoA) showed that there were significant differences in bacterial communities among animals' intestine, pond water, and sediment (p < 0.05). Venn analysis showed that intestinal bacteria shared a considerable number of OTUs (operational taxonomic units) with the sediment and water. SourceTracker analysis suggested that the contribution of sediment to the intestinal bacteria of S. constricta was much larger than that of rearing water. The Kruskal-Wallis test showed that the dominant bacterial taxa differed significantly between animals' intestines and the pond environment, and each of them has a unique bacterial composition. A network diagram indicated the complex positive and negative interactions between intestinal bacteria at the OTU level. Furthermore, BugBase analysis indicated that the bacterial contribution to potential pathogens in the animals' intestines is similar to that in sediments, suggesting that sediment was the main source of potential pathogens in S. constricta intestine. This study provided a theoretical basis for environmental regulation and disease prevention of S. constricta in aquaculture. KEY POINTS: • Culture environment had a significant effect on the intestinal bacterial community in S. constricta. • Sediment was a major source of intestinal bacteria and potentially pathogenic bacteria. • Complex positive and negative interactions existed between intestinal bacteria.