Pathway enrichment analysis

Pathway enrichment analysis was performed using online software; MetaboAnalyst (www.Metaboanalyst.ca) intended for the analysis of metabolomics data [28]. Briefly, we performed the analysis using only the metabolites that were up- or downregulated by at least twofold as indicated by our statistical analysis. Only metabolites that were present on all biological samples were considered for further analysis. The metabolites that passed our criteria were input into the software and the pathway enrichment analysis was performed [28]. The output of this algorithm marks a metabolic pathway if the input list of the metabolites suggests that the pathway associated with a specific pathway are present at levels that would not be expected by random chance.