Statistical comparison of metabolites and analysis of differential metabolites and key metabolic pathways. Statistical comparison of metabolites and analysis of differential metabolites and key metabolic pathways. (A) PCA score plot, OPLS-DA score plot, and permutation test plot of PLS-DA derived from the GC-TOF/MS metabolite profiles. Blue represents the infected piglets treated with exogenous fecal microbiota, and yellow represents the infected piglets without exogenous fecal microbiota intervention. The green circle represents the R2 value, the blue square represents the Q2 value, the green line represents the regression line of R2, and the blue line represents the regression line of Q2. (B) Heat map of hierarchical clustering analysis. The light blue boxes indicate an expression ratio less than the mean, and the dark red boxes denote an expression ratio greater than the mean. Tree clusters and their shorter Euclidean distances indicate higher similarities. (C) Metabolic pathway analysis of biomarker metabolites. The x axis represents the pathway impact, and the y axis represents the pathway enrichment. Larger sizes and darker colors represent higher pathway enrichment levels and higher pathway impact values, respectively. Saisai Cheng et al. mSystems 2018; doi:10.1128/mSystems.00137-18