Involvement of lipogenesis in the lower VLDL secretion induced by oligofructose in rats

Abstract

Dietary supplementation with oligofructose (OFS; 100 g/kg), a non-digestibleoligomer of β-D-fructose, decreases serum triacylglycerols in serum and VLDL of rats. In order to investigate the role of hepatic metabolism in the hypolipidaemic effect of OFS, male Wistar rats were fed on a standard diet with or without 1OOg Raftilose® P 95 /kg as OFS source for 30 d. OFS feeding (1) significantly decreased triacylglycerol and phospholipid concentrations in both blood and liver, (2) increased the glycerol-3-phosphate liver content but decreased the hepatic activity of glycerol-3-phosphate acyltransferase ( EC 2.3.1.15), suggesting a decrease in acylglycerol synthesis, (3) did not affect the blood non-caterified fatty acid concentrations, but (4) reduced by 54% the capacity of isolated hepatocytesto synthesize and secrete triacylglycerols from labelled acetate; the activity of fatty acid synthase, a key lipogenic enzyme was also significantly decreased. These findings suggest that OFS decreases serum triacylglycerols by reducing de nova fatty acid synthesis in the liver; the lower insulin level in the serum of OFS-fed rats could explain, at least partly, the metabolic effect induced by such nondigestible carbohydrates.