Fig 4. Metagenomic analysis of bacterial communities in the gill samples of zebrafish with TiO₂NP-induced injury.

(A) Relative abundance (% relative to the total) of the bacteria populations calculated for specific hypervariable regions of 16S ribosomal RNA through new-generation sequencing analyses. (B) Relative abundance (% counts of total) of the top 10 overall bacteria families (listed in the following paragraph). (C) Top 5 bacteria families in the Proteobacteria phylum (most abundant phylum; listed below). (D) Top 4 bacteria families in Bacteroidetes phylum (second abundant phylum; listed below).