3.5 | Abundance and composition of microbiota at phyla,
genera and species levels
A total of 37 phyla were obtained from all fish species (Supplementary
Figure 1S). We then selected the most abundant phyla with above 5%. We
obtained nine phyla classified as Proteobacteria, Firmicutes,
Bacteroidetes and Actinobacteria phyla with relatively high abundance,
representing 66.60%, 9.82%, 9.04% and 5.18%, respectively (Figure
4). Herbivorous fish species had significantly lower abundance of
Proteobacteria phylum than carnivorous and filter-feeding species
(p < .05). On the contrary, herbivorous fish species
had significantly higher abundance of Firmicutes and Bacteroides phyla
than omnivorous, filter-feeder and carnivorous species (p< .05). The omnivorous fish species had significantly higher
abundance of Verrucomicrobia phylum than omnivorous,
filter-feeder and herbivorous species (p < .05).
A total of 324 bacterial genera were obtained. We then removed
unidentified bacterial genera, and others and selected only those with
more than 0.5% abundance. The results on composition showed 45
bacterial genera were obtained (Supplementary Figure 2S). The four fish
species with different feeding habits had distinct microbiota
composition at genera for the nine phyla. Carnivorous and filter-feeder
species were dominated with Limnobacter species (25.05% and
23.56%) and Pseudomonas species (26.07% and 8.16%),
respectively. The microbiota of omnivorous species was mainly composed
of Rhodobacter species (14.99%), Zymomonas species
(10.63%), Clavibacter species (8.57%) and Luteolibacterspecies (6.68%). The herbivorous fish species was mainly composed ofBacteroides species (22.56%) and Citrobacter species
(9.43%).
We obtained 14 genera with significant differences in abundance of
microbiota (Table 3). The carnivorous fish species had significant
higher Acinetobacter species than the other three fish species
(p < .05). The omnivorous fish species had higher
abundance of Anaerospora , Arenimonas ,Dechloromonas , Deefgea , Luteolibacter andZymomonas genera than herbivorous and carnivorous fish species
(p < .05). The herbivorous fish species had
significantly higher Bacteroides genus than omnivorous,
carnivorous and filter feeder fish species (p < .05).Escherichia , Limnobacter and Mycoplana genera were
abundant flora of filter-feeder and carnivorous fish species, whilePseudomonas genus was abundant flora of filter-feeder and
omnivorous fish species.
A total of 2048 species of bacteria were obtained. Pseudomonas
stutzeri , Escherichia coli and Acinetobacter lwoffii were
the most abundant species (Figure 5). The Acinetobacter
johnsonii , Acinetobacter lwoffii , Escherichia coli andPseudomonas stutzeri had significant different abundance among
omnivorous, herbivorous, filter-feeder and carnivorous fish species
(p < .05). The carnivorous fish species had
significantly higher Acinetobacter johnsonii , Acinetobacter
lwoffii and Pseudomonas stutzeri than
the other three fish species
(p < .05). The filter-feeder and carnivorous fish
species had significantly higher Escherichia coli than omnivorous
and herbivorous fish species.