Chicory increases acetate turnover, but not propionate and butyrate peripheral turnovers in rats

Chicory roots are rich in inulin that is degraded into SCFA in the caecum and colon. Whole-body SCFA metabolism was investigated in rats during food deprivation and postprandial states. After 22 h of food deprivation, sixteen rats received an IV injection of radioactive ¹⁴C-labelled SCFA. The volume of distribution and the fractional clearance rate of SCFA were 0.25-0-27 litres/kg and 5.4-5.9%/min, respectively. The half-life in the first extracellular rapidly decaying compartment was between 0.9 and 1.4 min. After 22 h of food deprivation, another seventeen rats received a primed continuous IV infusion of ¹³C-labelled SCFA for 2 h. Isotope enrichment (¹³C) of SCFA was determined in peripheral arterial blood by MS. Peripheral acetate, propionate and butyrate turnover rates were 29, 4 and 0.3μmol/kg per min respectively. Following 4 weeks of treatment with chicory root or control diets, eighteen fed rats received a primed continuous IV infusion of ¹³C-labelled SCFA for 2 h. Intestinal degradation of dietary chicory lowered caecal pH, enhanced caecal and colonic weights, caecal SCFA concentrations and breath H₂.The diet with chicory supplementation enhanced peripheral acetate turnover by 25% (P = 0.017) concomitant with an increase in plasma acetate concentration. There were no changes in propionate or butyrate turnovers. In conclusion, by setting up a multi-tracer approach to simultaneously assess the turnovers of acetate, propionate and butyrate it was demonstrated that a chronic chicory-rich diet significantly increases peripheral acetate turnover but not that of propionate or butyrate in rats.