Changes in short-chain fatty acid plasma profile incurred by dietary fiber composition

Pigs were used as model for humans to study the impact of dietary fiber (DF), the main substrate for microbial fermentation, on plasma profile of short-chain fatty acids (SCFA; acetate, propionate, and butyrate). Six female pigs fitted with catheters in the portal vein and mesenteric artery and with a flow probe around the portal vein to monitor blood flow were used. Equal DF bread diets were prepared from white wheat flour with added purified wheat fiber (WFL), whole wheat grain (WWG), wheat aleurone flour (WAF), or rye aleurone flour (RAF). The main DF components of the WFL diet was cellulose >> arabinoxylan >> beta-glucan, whereas in the WWG, WAF, and RAF, diets it was arabinoxylan >> cellulose >> beta-glucan. The diets were fed to the pigs during 3 wk in a crossover design. Within an experimental week, WFL was supplied on Days 1 through 3 and WWG, WAF, or RAF was supplied during Days 4 through 7. Fasting blood sampling and flow measurements were performed on Days 4 through 7 and SCFA in plasma was analyzed by gas chromatography. The net SCFA absorption was similar for all diets (32-41 mmol/h). However, after switching to the arabinoxylan-rich diets, there was a shift in absorbed SCFA with a gradual higher net absorption of butyrate (2.4-4.0 vs. 1.6 mmol/h; P < 0.001). In conclusion, changing the fermentable substrate from predominantly cellulose to arabinoxylan-rich materials resulted in an altered SCFA uptake profile.