Digestibility and metabolizable energy of raw soybeans manufactured with different processing treatments and fed to adult dogs and puppies.

The objective of this study was to evaluate the apparent total tract digestibility (ATTD), ME, and fecal characteristics of adult dogs and puppies fed raw soybeans (RSB) and their by-products. Six treatments were evaluated: 1 reference diet (REF), based on a maize-poultry by-product meal, and 5 extruded diets containing 70% of the ingredients of the REF diet and 30% of a soybean processed product [defatted soybean meal (DSM), micronized soybeans (MSB), soybean meal (SBM), RSB, or toasted soybeans (TSB)]. Six adult dogs (5.8 yr old) and 6 puppies (5.1 mo old) were used in a study with a double Latin square design (6 × 6). Urease was reduced in all diets after extrusion, but trypsin inhibitor was reduced only in the diets containing SBM, DSM, and RSB. The ATTD of CP in DSM, SBM, MSB, TSB, and RSB were 85.1%, 85.2%, 88.4%, 84.7%, and 78.9%, respectively, for adult dogs. Soybean meal and DSM had the lowest ATTD of acid-hydrolyzed fat (AHF; 84.3% for both ingredients in adult dogs). The ATTD of DM and AHF in DSM and AHF in all soybean products were greater in puppies than adult dogs (P < 0.05). The ME content was greatest in MSB (21.39 MJ/kg) and least in DSM (15.23 MJ/kg). The feces of dogs fed soybean products were softer and had a lower pH (average of 5.91 vs. 6.05 for adult dogs fed soybean products and REF diets, respectively) and ammonia content (average of 3.82 vs. 4.32 g/kg for adult dogs fed soybean products and REF diets, respectively), except those fed RSB, which had similar fecal pH and ammonia values, compared with those fed the REF diet. Soybean products are good protein sources for both adult and growing dogs, provided they are heat treated before diet extrusion.