Fig. 2

Identification of the ruminal characteristic metabolites with varied dietary regimes. a PCA plot of metabolites detected by metabolome in the rumen liquid samples of lambs among four groups. b Pathway enrichment analysis was performed using the top 50 significantly (FDR < 0.05) different metabolites among groups, and the difference among the four groups was identified using the Kruskal–Wallis test (n = 8 per group). c WGCNA identification of rumen metabolite modules correlated with rumen development indexes, *P < 0.05, **P < 0.001. d The top 20 metabolites with the strongest influence on prediction accuracy of the random forest analysis presented in order of importance (top to bottom); the colored boxes on the right represented the relative level of the corresponding metabolites in each group. e The levels of 3-IAld and PGD2 in the rumen among four groups; means with different letters were significantly different via comparing any two diets by a fold-change threshold of 2 and a false discovery rate (FDR) < 0.05 from Wilcoxon rank-sum test and Benjamini and Hochberg multiple testing corrections. f Spearman’s correlation analysis between levels of 3-IAld and PGD2 and thickness of rumen epithelia and muscle layer. g The level of 3-IAld and PGD2 precursors in the rumen fluid; means with different letters were significantly different via comparing any two diets by a fold-change threshold of 2 and a false discovery rate (FDR) < 0.05 from Wilcoxon rank-sum test and Benjamini and Hochberg multiple testing corrections