Glucose-based oligosaccharides exhibit different in vitro fermentation patterns and affect in vivo apparent nutrient digestibility and microbial populations in dogs

To evaluate the potential of indigestible oligosaccharides (OS) to serve as "dietary fiber-like" ingredients, it is necessary to determine their exten t of indigestibility. In vitro fermentation characteristics of two novel OS , alpha-glucooligosaccharides (GOS) and a maltodextrin-like OS (MD), were c ompared to those of fructooligosaccharides (FOS), gum arabic (GA), guar gum (GG) and guar hydrolysate (GH). Total short-chain fatty acid (SCFA) produc tion (mu mol/g dry matter) as a result of MD fermentation was higher initia lly compared with GA (P < 0.01), but GA was more extensively fermented at 2 4 h (P < 0.01). Total SOFA production for GOS was similar to that for FOS, GG, GH and GA. In the second experiment, GOS and MD were added at 6% to an enteral formula control diet (Control) and fed to ileal-cannulated dogs in a 3 x 3 replicated Latin-square design. Ileal digestibility of glucose was lower (P < 0.05) and carbohydrate (CHO) numerically lower (P = 0.08) for bo th GOS and MD compared with the Control, Total tract digestibility of CHO a nd glucose was lower only for MD (P < 0.01) compared with the Control. Tota l fecal weights were higher (P < 0.01) for both GOS and MD treatments. Feca l concentration of bifidobacteria was numerically increased by GOS and MD s upplementation (P = 0.13 and 0.23, respectively). Thus, GOS and MD are indi gestible yet fermentable OS, and may act as "dietary fiber-like" ingredient s.