FIGURE 1

Effects of OTC administration on bacterial communities in zebrafish aquaria. (A) Bacterial communities in water, epidermal mucus and gut contents were analysed after feeding fish with OTC‐supplemented diet. Samples were also collected from a control aquarium without OTC administration. Genera corresponding to OTC‐resistant isolates identified by culture are highlighted in red. Data from replicate samples were combined and shown as stacked bar charts. (B) Beta diversity analysis using unweighted UniFrac distances was conducted to classify samples collected at Day 0, Week 1 and Week 4 from water, mucus and gut compartments. Groups of samples are indicated by dotted circles in different colours. (C) At Week 4, OTU abundances in OTC‐treated versus control groups were compared for water/mucus (4w_others ●) and gut (4w_gut ×) samples. Results are displayed in a volcano plot, showing log2 fold change relative to controls and –log10 FDR‐adjusted p values. OTUs with ≥ 4‐fold increases (red box) or decreases (blue box) and FDR ≤ 0.1 are highlighted.