Fig. 3

Taxonomic relative abundance according to phylum, family and genus. a Overall, taxonomic relative abundance in phylum and genus are shown for all groups. b In phylum, Firmicutes significantly increased (2Y versus (vs.) 1Y, p = 0.037) and Bacteroidetes reduced (2Y vs 8 W, p = 0.004; 2Y vs 1Y, p = 0.024) in the 2Y group compared to both 8 W and 1Y groups. Proteobacteria was increased (1Y vs. 8 W, p = 0.049) and Actinobacteria was decreased (1Y vs 8 W, p = 0.002; 1Y vs 2Y, p = 0.008) in the 1Y group. Cyanobacteria was increased in the aged group (1Y and 2Y) compared to the 8 W group (p = 0.002 and p < 0.001, respectively). c In family, Bacteroidaceae and Rikenellaceae were significantly more abundant and Muribaculaceae was significantly reduced in the aged group (1Y and 2Y) compared to the 8 W group (all p < 0.05). Prevotellaceae was significantly reduced in the 2Y group than in 8 W group (p < 0.001). d In genus, the aged group (1Y and 2Y) were increased Alistipes and Bacteroides, and decreased Paraprevotella compared to the 8 W group (all p < 0.01). The 2Y group revealed significantly decreased Prevotella than both 8 W and 1Y groups (all p < 0.05). *p < 0.05, **p < 0.01, and ***p < 0.001 by Kruskal–Wallis test followed by Dunn’s post hoc test. Data are presented as means ± standard error