Colonic fermentation of inulin increases whole-body acetate turnover in dogs

Abstract

Metabolism of acetate from colonic fermentation was investigated in dogs. Beagle dogs (n = 9) were fed a control diet for 17 d followed by a 3% inulin-enriched diet (from chicory) for 4 and 21 d. On 3 occasions, the dogs were administered simultaneously infusions of [1-13C]acetate i.v. and [1,2-13C2]acetate intrarectally. Peripheral acetate concentration and turnover did not change over time after consumption of an inulin-enriched diet for 4 d. After 21 d of consuming the inulin-enriched diet, the whole-body acetate turnover increased significantly by 31% from (mean ± SEM) 15.6 ± 2.2 to 20.4 ± 2.9 μmol/(kg·min) without a change in concentration. The rate of colonic acetate production that reached the peripheral circulation was 4.8 ± 1.8 μmol/(kg·min). However, no [1,2-13C2]acetate tracer was recovered in the peripheral circulation. The fraction of oxidized tracer was higher in the gut (64 ± 3%) than in peripheral circulation (46 ± 3%) in dogs fed an inulin-enriched diet for 21 d. In conclusion, colonic fermentation of inulin occurred and indirectly stimulated whole-body acetate turnover in dogs fed an inulin-enriched diet for 21 d. © 2005 American Society for Nutrition.