Isolated pectin (apple) and fruit pulp (mango) impact gastric emptying, passage rate and short chain fatty acid (SCFA) production differently along the pig gastrointestinal tract

Abstract Addition of fibre hydrocolloids to diets is expected to result in altered rates of digesta passage due to structuring effects, and the localised production of short chain fatty acids (SCFA) as fermentation products. However, it is not known whether these effects are similar for extracted and intrinsic plant cell wall fibre types. The purpose of this study was to determine the effect of isolated (apple) pectin and fruit (mango) pulp on gastric emptying (GE), passage rate, and SCFA production along the porcine gastrointestinal (GI) tract. Thirty pigs were fed a starch-based diet with or without addition of either pectin or mango pulp over a 21-day intervention trial. Indigestible solid phase constant markers as well as solid and liquid phase pulse markers (fed 2, 4 or 6 hours prior to sampling) were fed to measure apparent mean retention time (aMRT) and GE, respectively. The GI tract was divided into nine sections and analysed for digesta contents, marker recovery and SCFA production. The control diet showed significantly faster GE of the liquid digesta phase compared to solid phase, while the addition of pectin significantly delayed GE of the solid phase. The addition of pectin and mango pulp each increased digesta water content, and the pectin diet significantly decreased aMRT along the small intestine. SCFA content was increased significantly in both isolated pectin and mango pulp diets, particularly in the caecum and large intestine, with the isolated pectin diet favouring butyrate production and the mango pulp diet favouring propionate production.