Evaluation of oligosaccharide addition to dog diets: influences on nutrient digestion and microbial populations

Seven adult mixed breed female dogs (17.4±2.9 kg) surgically fitted with ileal T-cannulas were used in a 4×7 incomplete Latin square design experiment to evaluate oligosaccharide supplementation on dry matter (DM), nitrogen (N), ammonia, volatile fatty acid (VFA), bacteria, blood glucose concentrations, ileal pH, and fecal consistency. Fructooligosaccharide (FOS), mannanoligosaccharide (MOS), and xylooligosaccharide (XOS) were added at 5 g/kg of diet DM. There were no differences in DM digestibility, diet or fecal N, N digestibility, ileal or fecal ammonia, fecal consistency, ileal bacteria colony forming units, blood glucose, or ileal pH. Ileal butyrate proportion tended to be greater (P=0.07) in the control diet (0.076 of total VFA) compared with the oligosaccharide supplemented diets and lower (P=0.07) for the MOS diet compared with the FOS and XOS diets. Ileal propionate tended to be higher (P=0.09) in MOS (0.198 of total VFA) than FOS and XOS. Fecal bifidobacteria numbers were unaffected by dietary treatment. Fecal Clostridium perfringens tended to be lower (P=0.09) in MOS when compared to FOS and XOS. Oligosaccharides had relatively minor effects on bacterial growth in the large intestine and VFA proportions in the small intestine of the canine. For oligosaccharide feeding to cause microbial changes in the canine greater amounts of oligosaccharide may be required, or it may require application in select dietary situations.