Relative abundance of potentially pathogenic bacteria according to BugBase analysis based on the 16S rRNA gene sequencing dataset. The outcome was grouped according to the gut segments and age. Gut segments were ileal chymus (IC), ileal mucosa (IM), and caecum chymus (CC). The relative abundance is presented on the y-axis, which is calculated by closed/open OTU picking ratio. Differences between groups were assessed using Mann–Whitney–Wilcoxon test, with Benjamini–Hochberg false discovery rate (FDR) correction. FDR-corrected p-values below 0.05 were considered significant. a, b: Averages with different letter marks differ significantly (FDR p < 0.05).