Evaluation of Fermentability of Whole Soybeans and Soybean Oligosaccharides by a Canine In Vitro Fermentation Model

Abstract

Soybean oligosaccharides (OS) have been recognized as a prebiotic that can be fermented in the colon, resulting in short-chain fatty acid (SCFA) production that can be used as an energy source for colonocytes, supporting cell differentiation and gut health. The objective was to determine the effects of WSBOS on in vitro fermentation, using dog feces as inoculum. Treatments included total dietary fiber (TDF) residues from WSB, soybean hulls (SH), pea fiber (PF), and beet pulp (BP), as well as WSB TDF residue plus soybean OS (WSBOS) and WSB TDF residue plus raffinose, stachyose, and verbascose (WSBRSV). Fresh fecal samples were collected from dogs and maintained in anaerobic conditions until substrate inoculation. Test tubes containing fiber sources and inoculum were incubated for 4, 8, and 12 h at 39 °C. Organic matter disappearance (OMD), pH, and SCFA were measured. The WSBOS and WSBRSV had greater (p < 0.05) OMDs than BP. Butyrate production was greatest (p < 0.05) for WSBOS (294.7 µmol/g) and WSBRSV (266.1 µmol/g), followed by BP (130.3 µmol/g) and WSB (109.2 µmol/g), and lowest (p < 0.05) for PF (44.1 µmol/g). The production of total SCFA was greatest (p < 0.05) for BP and WSBOS, followed by WSB, and lowest (p < 0.05) for PF. In conclusion, WSB has the potential as a prebiotic demonstrating greater butyrate production than BP in a canine in vitro fermentation model due to the fermentation of both OS and fiber in WSB. Further animal feeding studies are needed to determine the appropriate amount of WSB in canine diets.