Abstract:To reveal the differences in the microbial composition of skin mucus and the habitat of Chinese sturgeon (Acipenser sinensis) in different physiological states, we compared the community structure of the skin mucus flora of healthy and sub-healthy Chinese sturgeons and explored the correlation between the structure of the bacterial community and physiological state of Chinese sturgeons. Skin mucus and aquaculture water of healthy and sub-healthy Chinese sturgeons were collected, and the bacterial flora composition was analyzed using high-throughput sequencing technology. The results showed that microbial diversity and richness were significantly higher in the sub-healthy group than in the healthy group (P<0.05). Statistical analysis of the sequences showed that many unique operational taxonomic units (OTUs) were present in the mucus samples compared with the aquaculture water, and the number of shared OTUs with the aquaculture water changed according to the health status. The principal component and principal coordinate analyses between different groups showed a strong separation tendency, and the relative distance between samples within groups was small. There were significant differences in the composition and dominant species of skin mucus and aquaculture water communities of Chinese sturgeons at the phylum and genus levels. The dominant phyla in the water were Proteobacteria (31.84%) and Firmicutes (24.37%); the dominant phyla in the healthy group were Proteobacteria (55.23%) and Bacteroidetes (21.00%); and the percentage of Proteobacteria (40.23%) in the sub-healthy group, but the proportion of Acidobacteria (18.29%), Gemmatimonadetes (10.08%), Actinobacteria, and Verrucomicrobia increased. The dominant flora in water samples were Sphaerochaeta (10.56%) and Cloacibacillus (7.95%). The dominant flora in the healthy group were Ralstonia (19.83%) and Mucilaginibacter (8.11%). The dominant flora in the sub-healthy group, compared to the healthy group, consisted mainly of Sphingomonas (16.71%) and WPS-1_genera_incertae_sedis (5.05%). Functional prediction revealed that the functional abundance of flora in the sub-healthy group showed a decreasing trend compared with that in the healthy group, including environmental adaptation, biological metabolism, and signal transduction. Similarity and difference analysis of the mucus microbiome of Chinese sturgeons in different physiological states and aquaculture water showed that it changed with the physiological state, and the genus Sphingomonas was the dominant genus of mucus flora in the sub-healthy group, which can be used as a health marker. By comparing the microbial communities in the skin mucus of healthy and sub-healthy Chinese sturgeons, different microbial community structures were observed in different health states, which provides a new perspective for their healthy culture and monitoring.
