Advanced analysis of bacterial communities in cecal digesta. (A) Principal component analysis of cecal digesta of broilers receiving basal diet without treatment (C), basal diet plus enramycin (A), basal diet plus Bacillus species–fermented products (SYN), basal diet plus essential oils (EO), and basal diet plus Bacillus species–fermented products and essential oils (SYN+EO; n = 4). Principal coordinate analysis of quantitative traits (unweighted UniFrac distances) (B), and qualitative traits (weighted UniFrac distances) (C) of cecal bacterial communities of the control, A, SYN, EO, and SYN+EO groups (n = 4).