Published in the Journal of Animal Science, this study by Isabella Corsato Alvarenga and colleagues explored how food processing methods influence nutrient utilization and colonic health in adult dogs. The researchers tested three corn-based diets—pelleted, baked, and extruded—using corn as the only starch source, and compared them to a baked control diet in which corn was replaced by dextrose.
Processing methods significantly affected the degree of starch cooking and resistant starch (RS) content. The extruded diet had the highest starch cook and lowest RS, while the pelleted diet retained the most RS due to lower thermomechanical energy. The baked diet showed intermediate properties. Twelve adult dogs were fed each treatment in a 4 × 4 Latin square design, and their feces were analyzed for consistency, digestibility, short-chain fatty acids (SCFAs), and microbial diversity.
Results revealed that the extruded food achieved the highest apparent total tract digestibility (ATTD), followed by baked and pelleted diets. Dogs consuming the extruded diet also showed the best fecal quality and SCFA profiles, particularly higher butyrate levels, which support gut health. In contrast, the dextrose control caused osmotic diarrhea, high fecal pH, and low SCFAs, indicative of microbial imbalance or dysbiosis.
Interestingly, despite the higher resistant starch content in the pelleted diet, this did not translate into improved fermentation or better colonic function. Microbiome analyses showed similar bacterial diversity among dogs fed the corn-based diets, suggesting that processing affects digestion and fecal quality more than microbial composition.
Overall, the study demonstrates that extrusion processing yields superior outcomes in terms of nutrient digestibility and gastrointestinal stability. The authors conclude that extrusion may be the most effective method for producing corn-based dog foods that balance nutrient absorption and gut health.
Source: Alvarenga, I. C., Lierz, R., Chen, Y., Lu, A., Lu, N., & Aldrich, C. (2024). Processing of corn-based dog foods through pelleting, baking and extrusion and their effect on apparent total tract digestibility and colonic health of adult dogs. Journal of Animal Science, 102. Published March 30, 2024.
