This study investigated the effects of exogenous enzymes supplementation on kibble diets for dogs formulated with soybean meal (SBM) as a substitute for poultry by-product meal (PM), highlighting nutrient digestibility, fermentation products formation, post-prandial urea response and selected fecal bacteria counts.
Two kibble diets with similar compositions were used in two trials: a PM-based diet (28.9% of PM; soybean hulls as a fiber source) and an SBM-based diet (29.9% of SBM). Each of two experiments followed a block design with six dogs per diet. Data were submitted to analysis of variance and means compared by orthogonal and polynomial contrasts (p < 0.05).
In both experiments, nutrients and energy digestibility did not differ between diets (p > 0.05). SBM consumption resulted in increased fecal moisture and production (p < 0.05), without effect on fecal score. Higher concentration of propionate, acetate and lactate, and lower ammonia and pH were found in the feces of dogs fed SBM (p < 0.05). Higher post-prandial urea was verified in dogs fed SBM (p < 0.05). In experiment 2, the addition of enzymes increased fecal concentration of propionate, acetate and total short-chain fatty acid (p < 0.05) and tended to reduce post-prandial urea concentration (p = 0.06).
Although with similar digestibility, SBM shows a worse utilization of absorbed amino acids than the PM. Soybean oligosaccharides can beneficially change gut fermentation product formation. Enzymes can increase the gut fermentation activity and improve the SBM proteic value.
Source: L. Tortola et al., 2013. Enzyme effects on extruded diets for dogs with soybean meal as a substitute for poultry by-product meal. JAPAN online May 2013. doi: 10.1111/jpn.12009