Comparison of fermentation of selected fructooligosaccharides and other fiber substrates by canine colonic microflora

Objective-To compare fermentation characteristics of fructooligosaccharides (FOS) and other fiber substrates that are commonly found in canine diets. Sample Population-Fecal samples from 3 adult dogs. Procedure-The ability of fiber substrates to be used in microbial fermentation reactions was assess ed by use of an in vitro fermentation system. Dogs were fed a commercially available food, and feces were collected for use as the microbial inoculum. Substrates used were beet pulp, cellulose, soy fiber, mannanoligosaccharid es (MOS), FOS, and 4 inulin products (inulin 1, 2, 3, and 4). Each substrat e was incubated anaerobically with fecal inoculum and growth media for 6, 1 2, and 24 hours, and production of short-chain fatty acids (SCFA) was measu red. Results-Total production of SCFA was higher for fermentation of the 4 inuli n products and FOS, whereas fermentation of beet pulp, MOS, and soy fiber r esulted in moderate concentrations of SCFA. Fermentation of cellulose produ ced the lowest concentrations of total SCFA without detection of butyrate o r lactate. Butyrate production was greatest for fermentation of the 4 inuli n products and FOS. Total lactate production was greatest for FOS and inuli n 4. As expected, production of SCFA increased for all substrates as fermen tation time increased. Conclusions and Clinical Relevance-Canine fecal microflora ferment FOS-cont aining substrates in a similar manner, with little fermentation of cellulos e-based carbohydrates. Furthermore, results of an in vitro fermentation sys tem indicate that fiber type affects the metabolic activity of microorganis ms, thus influencing the amount and nature of the end products of fermentat ion.