Fig. 7

The calculated causal relationship of the bacteria strongly associated with reproductive performance was visualized via linear non-Gaussian acyclic model (DirectLiNGAM) analysis. a The arrow indicates the trend of the causal contribution. The number indicates the value of the causal contribution calculated via DirectLiNGAM analysis. The negative and positive values indicate the negative and positive causal contributions, respectively. “AI number” is displayed in underlined black bold type. Bacteria written in red indicate bacteria for which a direct relationship with “AI number” was observed. The sharp (#) indicates bacterial genera whose abundance increased in the superior group in Fig. 3. The cross (♰) indicates bacterial genera with significantly different correlation values in Fig. 4. b Relative abundance of bacterial taxa directly associated with AI number. The data are presented as the mean ± standard error of the mean. Relative abundances of the other bacterial taxa are shown in Fig. S5