Two studies were conducted using adult dogs to evaluate the effect of increasing the inclusion of soybean meal (SBM) in an adult dog food on body composition, hematological and biochemical blood analyses, and total tract nutrient digestibility. Nutritionally complete and balanced diets were formulated with commercial SBM (48% CP) to replace 0, 10, 20, or 30% of the protein provided by dried chicken protein. In study 1, diets were fed during a 24-wk feeding trial using 36 female adult hounds to evaluate food intake, body weight, body composition, and blood measurements. There were no diet-related differences in food intake or body weight. All diagnostic blood components remained within normal physiological ranges for healthy, adult dogs

In the second study, diets were evaluated in a digestibility study using 12 adult dogs in a 4 × 4 Latin square design. Increased SBM inclusion was associated with linear increases in the digestibility of crude protein, fat and crude protein retention (P < 0.05). Linear reductions in fecal DM content (P < 0.01) and increased fecal output (P < 0.05) were noted with increased SBM inclusion. The researchers concluded that partial replacement of dried chicken protein with SBM in a nutritionally complete and balanced diet does not compromise the nutritional status and long-term health of adult dogs.