Dietary oat beta-glucan reduces peak net glucose flux and insulin production and modulates plasma incretin in portal-vein catheterized grower pigs.
J Nutr. 2010 Sep;140(9):1564-9. Epub 2010 Jul 21. PMID: 20660287
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
Net glucose and SCFA flux and insulin secretion into the portal vein might be associated with the incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Our objectives were to clarify this association and study the impact of 2 doses of dietary oat beta-glucan on the variables. Three 35-kg portal vein-catheterized pigs were fed 3 diets containing 0, 3, or 6% oat beta-glucan concentrate (BG0, BG3, and BG6) for 7 d in a repeated 3 x 3 Latin square. On d 7, blood was sampled for 12 h postprandially. Net glucose flux and apparent hormone production were calculated from plasma portal-arterial differences x flow. Postprandially, pigs fed BG6 had lower (P<0.05) portal glucose at 15, 30, and 45 min and a lower (P<0.05) net glucose flux during the first hour. Pigs fed BG6 tended to have lower (P<0.10) portal C-peptide without lowering insulin, indicating that pigs fed BG6 had lower actual insulin release combined with a higher prehepatic retention of insulin. Pigs fed BG6 had lower (P<0.05) portal GIP and GLP-1, which in turn were correlated (R(2) = 0.81 and 0.88, respectively; P<0.01) with portal glucose. Pigs fed BG3 and BG6 had a higher (P<0.05) net SCFA flux than pigs fed BG0, indicating increased fermentation. In conclusion, dietary supplementation of 6% oat beta-glucan concentrate decreased net glucose flux, increased net SCFA flux, and decreased peak apparent insulin production, changes that were associated with GIP and GLP-1 mediation.