PSVIII-8 Evaluation of barley protein in adult dog diets and the impact on digestibility, stool quality, and palatability.

Abstract Barley protein concentrate (BP) is a new (>55% protein) ingredient that is being commercialized for use in pet foods. In this study, we evaluated the impact of BP dietary inclusion on nutrient digestibility, stool quality, and palatability in adult dogs. The high-protein, chicken-based test diets were formulated to include BP at 5% or 10%, substituting pea protein, to match protein, fat, and crude fiber. Diets were formulated to meet AAFCO Adult Maintenance ranges. The study was approved and followed by the facility’s Institutional Animal Care and Use Committee. The palatability assessment consisted of a 2-bowl preference test over a 2-day period (n=30 each) to determine intake ratio (IR) between test diets (5% and 10% BP) and vs. control. Total tract nutrient digestibility was evaluated (N=6 per diet) with 5 days of diet acclimation followed by 5 days of total fecal collection. Fecal samples were scored to assess stool quality on a 1-5 scale, where 1= nonformed/ diarrhea and 5=hard formed. Digestibility and stool quality data were analyzed by Mixed procedure of SAS 9.4 (SAS Inst. Inc., Gary, NC), with treatment as the fixed effect. An LSMEANS statement was used to calculate the least square means for each treatment with Tukey-Kramer adjustment for multiple comparison among treatments. With P < 0.05 considered statistically significant, no differences were observed between diets for dry matter digestibility (all > 77%). Crude protein digestibility (all > 80%) was similar for 5% vs control, but 10% BP inclusion tended to be lower than control (P < 0.053). Fat digestibility was slightly higher (P < 0.05) for 5% inclusion (93.9%) vs. control (92.7%) and 10% inclusion (92.3%) (P < 0.05). Stool scores were similar between groups (all averages between 3.3-3.5). The 5% BP diet had similar palatability relative to control (IR=57:43, 5% BP vs. control). However, we observed that 10% BP inclusion had lower palatability compared to control (64:36, 10% BP vs. control; P < 0.05), with no significant difference found for 5% vs 10% (58:42, 5% BP vs. 10%; P > 0.10). In summary, small changes were observed for digestibility but not stool quality with BP inclusion of up to 10%. However, palatability may be impacted at higher inclusion levels in adult dog diets.