3.1 | The faster and slower regeneratingApostichopus japonicus have different intestinal microbial
communities
We assessed the intestine regeneration rate of the faster and slower
regenerating A. japonicus individuals, including intestinal
length and weight. The intestinal length of the faster regenerating
individuals was significantly longer than that of the slower
regenerating individuals during intestine regeneration (10-14 d). The
intestine of the faster regenerating individuals was also heavier than
that of the slower regenerating individuals (Figure 1). There were
significant differences between the two groups. Thus, we assessed the
intestinal microbiome of the faster and slower regenerating groups.
At 97% sequence identity, a total of 3,147 OTUs were obtained across
all samples. The samples from the faster regenerating group contained
2,373 OTUs (on average), while the slower regenerating group samples
contained 2,365 OTUs (on average)
(Table
S1). The Shannon indices were 5.69 and 4.77, and the Chao1 richness
values were 897 and 688 OTUs in the faster and slower regenerating
groups, respectively. The results indicated that the alpha diversity of
the bacterial community was different between the faster and slower
regenerating groups (F and S) (Figure S1).
Analysis of the intestinal microbiota revealed that the faster and
slower regenerating individuals had distinct taxonomic compositions
(Figure 2a, Figure S1). In the F samples, Flavobacteriales (average
21.3%) and Rhodobacterales (19.3%) were the most abundant orders,
represented mainly by the Flavobacteriaceae (20.3%) and
Rhodobacteraceae (19.3%) families, respectively. Compared to that in
the F samples, a markedly varied profile was detected in the S samples
(Figure 2a, Figure S1). The Micrococcales order prevailed (average
27.9%) and was represented mostly by the Microbacteriaceae (27.7%)
family. Rhodobacterales (13.3%) was the next most abundant order,
represented by the Rhodobacteraceae (13.3%) family. The reads
affiliated with Flavobacteriales were significantly more abundant in the
faster regenerating individuals than in the slower regenerating
individuals (Figure 2b).