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

Abstract

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 radioactive14C-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 of13C-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 0·3 μmol/kg per min respectively. Following 4 weeks of treatment with chicory root or control diets, eighteen fed rats received a primed continuous IV infusion of13C-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.