Dog foods were produced via extrusion, baking, and pelleting to yield increasing amounts of starch resistant to digestion (resistant starch [RS]). The foods were compared to a negative dextrose control that contained dextrose in place of starch. Amounts of cooked starch and RS were confirmed by in vitro methodologies. These foods were fed to healthy adult dogs in a Latin square design. Feces were scored for quality and collected to calculate apparent digestibility. Fresh feces were also collected for fecal short-chain fatty acids and microbiome evaluations. The corn-based extruded kibble was more digestible, followed by the baked and pelleted treatments. The extruded treatment produced stools closest to the ideal, but dogs fed the pelleted and baked also produced acceptable feces. The SCFA composition in the feces of dogs fed extruded was like the pelleted treatment, with a higher tendency to produce butyrate. Changes in fermentation were not a consequence of differences in microbiome composition among dogs fed corn-based foods. Dogs fed the control had osmotic diarrhea, with a higher fecal pH and higher proportions of branched-chain fatty acids, which was undesirable. The extruded food performed better overall than baked and pelleted, but they were all acceptable as food forms for dogs.

Read the full article in the Journal of Animal Science.