Results of rumen metabolites analysis. (A) Principal component analysis (PCA) of rumen metabolites. (S1-4: SUS1-4, T1-4: TOL1-4). (B) Partial least squares-discriminate analysis (PLS-DA, of rumen metabolites. The x-axis and the y-axis indicate the first and second principal components, respectively. Dots represented samples and the distances among dots demonstrated the similarities among samples according to the rumen metabolites. (C) Classification of rumen differential metabolites (SUS/TOL, variable importance in the projection [VIP] > 1.0, P < 0.05). (D) Metabolic routes for propionate and butyrate production by direct conversion from carbohydrates. G: glucose; P: phosphate; F: fructose; The red arrows indicate a significant higher in rumen metabolites in SUS group. (E) The fold change of different metabolites involved in carbohydrates metabolism (SUS/TOL, VIP > 1.0, P < 0.05). (F) The fold change of amine in rumen metabolites. (G) Metabolic pathways were analyzed based on different metabolites (Impact > 0.1, P < 0.05).