Bacterial community compositions of crab intestine, surrounding water, and sediment in two different feeding modes of Eriocheir sinensis

The aim of this study was to reveal the relationship between bacterial communities in the intestine of the Chinese mitten crab Eriocheir sinensis and in the surrounding environment, and to compare these bacterial communities in two different feeding modes: iced fresh trash fish mode and formulated diet mode. We investigated bacterial communities of samples obtained from different feeding modes through high-throughput sequencing technology. Compared with water and sediment, crab intestine had the lowest OTU richness and bacterial community diversity. There were no significant differences in bacterial diversity and OTU richness of water, sediment, and crab intestine between these two feeding modes. Bacteroidetes and Proteobacteria were the most abundant phyla in water, sediment, and crab intestine. Chloroflexi, Actinobacteria, and Tenericutes were the dominant phyla in water, sediment, and crab intestine, respectively. Analyses demonstrated a low average similarity and a small number of shared OTUs between water, sediment, and crab intestine in the two feeding modes. In the iced fresh trash fish feeding mode, there was a total of 86 shared OTUs among three habitats, accounting for 25.60%, 6.95%, and 2.77% of total OTUs in the intestine, surrounding water, and sediment, respectively. In the formulated diet feeding mode, there was a total of 64 shared OTUs among three habitats, accounting for 18.99%, 8.85%, and 2.08% of total OTUs in the intestine, surrounding water, and sediment, respectively. The results suggested that feeding modes did not affect the microbial community in water, sediment, and crab intestine. This study is the first to report on the relationship of bacterial communities in the crab intestine, surrounding water, and sediment, which can expand our knowledge of the bacterial community in E. sinensis culture ecosystems.