Abstract
Dietary fiber is an important component of pet food that helps to promote colonocyte health by favoring saccharolytic fermentation and short-chain fatty acid production in addition to modulating gut microbiota and aiding laxation. The objective of this study was to evaluate and compare the effects of miscanthus grass fiber, prebiotic fiber blends, and traditional dietary fiber sources on apparent total tract digestibility, fecal metabolites, and gastrointestinal intolerance in adult canines. Animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee. Twelve female adult beagles were randomly assigned to one of six treatments containing cellulose, beet pulp, miscanthus fiber, or a blend of miscanthus fiber and tomato pomace, miscanthus fiber and resistant starch, or miscanthus fiber and fructooligosaccharide in a replicated 6x6 Latin square design. All treatment diets were formulated to meet or exceed AAFCO nutrient profile (2018). The dogs received each treatment for 21 d, with 17 d of diet adaptation followed by 4 d of total and fresh fecal collection. No difference in fecal score was observed (P < 0.05). Dogs fed the beet pulp diet had the highest organic matter digestibility and total dietary fiber digestibility (P < 0.05) when compared to all other treatments. Crude protein digestibility was significantly higher (P < 0.05) for the cellulose, miscanthus fiber, and miscanthus and resistant starch blend than the beet pulp diet. Fecal total short-chain fatty acid concentration was greatest for beet pulp and lowest for the cellulose treatment (P < 0.05) with the miscanthus fiber and miscanthus fiber blends with resistant starch, fructooligosaccharide, and tomato pomace being intermediate. No difference was observed in fecal total branched-chain fatty acid concentration (P < 0.05). The data suggest that miscanthus fiber is an adequate and functional source of fiber in extruded canine diets, and comparable to the traditional fiber source, cellulose.