Fig 7.

VOC volcano plot. Statistically significant VOC emerged from non-parametric Wilcoxon rank-sum test combined with FC analysis. Because of the chosen comparison direction of placebo/probiotic, increased and decreased metabolite concentrations in the placebo group were marked as down (blue) and up (red), respectively. The −log10 (P-values) is meaningful for the level of significance of each VOC and was plotted versus the log2 fold change. It represents the difference between the levels of expression for each VOC between the two groups at T1 (10 days of GFD) panel A, T5 panel B, and T6 panel C (20 days of 10 g/day gluten intake, of which the last 10 days were the wash-out). Pairwise comparison analysis based on the non-parametric Wilcoxon rank-sum test combined with FC was applied to evaluate differences between the levels of expression for each VOC between the two groups at T1, T5, and T6.