Fig. 4

The diversity of fish gut microbiome at 105 days of feeding (dof). a Alpha diversity (richness and Shannon diversity index) of gut microbiome. Values are presented as mean ± standard error, the absence of letters above error bars indicates no significant differences between the four treatments. b Venn diagram showing the shared amplicon sequence variants (ASV with prevalence > 33% in each treatment) between the gut microbiome from the four treatments. c Principal component analysis (PCoA) showing the distribution of gut microbiome from the four treatments, P values were calculated based on two-way PERMANOVA. Capital letters refer to replicate tanks (A, B. C), numbers refer to fishes sampled for gut microbiome per tank (1, 2, 3). d Heatmap showing the relative abundance (RA) of the indicator species selected from the four treatments, indicator species are coloured according to their phylum taxonomy. FTS flow-through system, BFS biofloc system, M moderate NSP diet, H high NSP diet