3.5 | Intestinal microbiota depletion promotes the potential key players in the regenerating intestine ofApostichopus japonicus
At 97% sequence identity, the CV samples contained 1,877 OTUs, the samples from the XGF group contained 1,620 OTUs, and the GF samples contained 1,228 OTUs (Table S2). We analyzed both genus and species numbers in the samples from the 3 groups to further identify the differences in the bacterial communities of A. japonicusintestines during regeneration stages. The CV, XGF and GF groups contained 597, 578 and 446 genera, respectively. The number of OTUs and bacterial species from GF samples were significantly lower than those from CV samples. No developmental defects or regrowth rate differentiation were observed in the XGF samples compared to those in the CV samples; therefore, we compared and analyzed the CV and GF groups in this study.
Analysis of bacterial communities revealed distinct taxonomic compositions between the CV and GF samples at the order and genus levels. In CV samples, the Oceanospirillales order prevailed (average of 41.51% of all the reads) and was represented mostly by the Halomonadaceae (41.04%) family, mainly related to Halomonas(41.03%) genus. Alteromonadales (14.87%) was the next most abundant order, represented mainly by the Pseudoalteromonadaceae (7.74%) and Colwelliaceae (5.24%) families and the Pseudoalteromonas(7.11%) and Colwellia (5.15%) genera. The next most abundant order was Burkholderiales (8.08%), which was represented mainly by the Burkholderiaceae (7.41%) family and the Ralstonia (7.29%) genus (Table 1, Table S3-4).
In GF samples, the most abundant order was Flavobacteriales (52.68%), which was represented mostly by the Flavobacteriaceae (50.15%) family, with Flavobacterium , Polaribacter ,Flavobacteriaceae_uncultured and Crocinitomix comprising 41.78%, 2.85%, 1.5% and 1.08% of the total, respectively. Burkholderiales (average 9.25%) was the next most abundant order, represented mainly by the Burkholderiaceae (8.18%) family, mainly related to the Ralstonia (7.92%) genus. Rhodobacterales was also present (6.59%), mainly related to the Rhodobacteraceae (6.59%) family (Table 1, Table S3-4).
The average abundances of Flavobacteriaceae (4.42%) and Rhodobacterales (3.91%) (the potential key players) in CV samples were significantly lower than those in GF samples.