Microbiota comparison in the intestine of juvenile Chinese mitten crab Eriocheir sinensis fed different diets

Intestinal microflora, as a component of the host bacteria ecosystem, can influence the healthy growth of crab. The aim of this study was to determine the intestinal microflora of the juvenile Chinese mitten crab Eriocheir sinensis with different feeding modes. We investigated the bacterial communities of crab intestine resulting from three different feeding modes using high-throughput sequencing technology, including traditional, formulated, and mixture (combined traditional and formulated) diet feeding modes. Intestinal microbiota biodiversity and richness were not affected by the different feeding modes. The most dominant community members at the phylum level were Tenericutes, Bacteroidetes, Firmicutes, and Proteobacteria. Significant differences were only observed in the relative abundance of Tenericutes (P = 0.0390) and Proteobacteria (P = 0.0273) in the female crab intestines among different feeding modes. The seven most abundant genera in the intestine of male and female crabs included Candidatus Bacilloplasma, Candidatus Hepatoplasma, Prolixibacter, Vibrio, Dysgonomonas, Coprobacillus, and Lactovum. Moreover, high average similarity of the microbial community was observed in the intestine of male and female crabs among the three different feeding modes and also between male and female crabs within these feeding modes. The most abundant genera in the latter ( > 10%) were Candidatus Bacilloplasma, Candidatus Hepatoplasma, and Prolixibacter. In addition, unique microbial genera were found in male or female crab intestine among different feeding modes. Differences were also observed in the relative enrichment of the dominant bacteria in male and female crab intestine among different feeding modes. Nevertheless, these findings suggested that the microbial communities in the intestines of crabs showed overall high average similarity among the three feeding modes or between the sexes as reflected by the biodiversity, richness of intestinal microbiota, and the most dominant community members at the phylum and genera levels. The results of this study provide a theoretical reference regarding the diversity of intestinal bacteria in juvenile E. sinensis.