PSV-B-21 - Evaluation of whole soybeans as an ingredient in dog diets: apparent total tract digestibility and stool quality of extruded diets with graded levels of dehulled whole soybeans by dogs

Increasing the amount of liquid fat to the ration during extrusion can negatively affect product density and product expansion. Ingredients, like whole soybeans (WSB), which are high in fat may aid increased energy density while avoiding production issues. In a preliminary extrusion project, the effects on the process of foods were evaluated, followed by animal evaluation. The objective of this study was to determine the effect of dehulled WSB on nutrient digestibility and stool quality by dogs. Experimental diets were extruded with 0%, 10%, 20%, and 30% WSB (WSB0, WSB10, WSB20, and WSB30, respectively). Seven castrated male and three spayed female Beagles of similar age (6.25 ± 0.452 years) were individually housed and fed the experimental diets. The study was designed as replicated 4 × 4 Latin square where dogs were allowed 9-d adaptation followed by 5-d total fecal collection for each period. Titanium dioxide was added to all diets (0.4%) to serve as an indigestible dietary marker to determine apparent total tract digestibility (ATTD). Least-square means of fecal parameters and ATTD were analyzed with a single degree of freedom contrasts and significance at α = 0.05. There was no difference among treatments for food intake or fecal scores. However, there were linear increases (P < 0.05) in DM fecal output, as is fecal output, fecal moisture, and defecation frequency stools/day as WSB increased in the diets. Apparent total tract digestibility of dry matter, crude protein, acid hydrolyzed ether extract, and gross energy decreased linearly as dogs were fed increasing levels of WSB in the diets (P < 0.05). In conclusion, additional thermal processing before extrusion may improve nutrient digestibility, although stool quality was not affected by the inclusion of WSB.