Hanne Christine Bertram

Scope Liver is an important metabolic organ regulating whole‐body homeostasis. This study aims to investigate how prebiotic‐induced changes in the metabolic activity of the gut microbiome (GM) and dietary calcium depletion modulates the hepatic metabolome and transcriptome. Methods and results The serum metabolome, liver metabolome, and transcriptome are determined on samples from ovariectomized (OVX) rats fed a control diet (Control, n = 7), a control diet supplemented with 5% w/w inulin (Inulin, n = 7), or a calcium‐deficient diet (CaDef, n = 7). Inulin fortification is associated with higher serum concentrations of acetate, 3‐hydroxybutyrate, and reduced concentration of dimethyl sulfone, revealing that changes in the metabolic activity of the GM are reflected in circulating metabolites. Metabolomics also reveal that the inulin‐fortified diet results in lower concentrations of hepatic glutamate, serine, and hypoxanthine while transcriptomics reveal accompanying effects on the hepatic expression of ferric iron binding‐related genes. Inulin fortification also induces effects on the hepatic expression of genes involved in olfactory transduction, suggesting that prebiotics regulate liver function through yet unidentified mechanisms involving olfactory receptors. Conclusion Inulin ingestion impacts hepatic gene expression and is associated with an upregulation of ferritin synthesis‐related genes and liver ferritin content.