Evaluation of Faba Beans (Vicia faba L.) As a Dietary Ingredient in Dog Diets

Legumes are increasingly popular in pet foods. Dehulled faba beans (FB) are a legume well researched in human diets, but not pet foods. Therefore, the objective of this work was to evaluate the effect of graded levels of FB in dog diets. Four experimental diets were extruded in a single-screw extruder (Model 525; ExtruTech, Inc. Sabetha, KS) in which FB were included at 0% (FB0), 10% (FB10), 20% (FB20), and 30% (FB30) in exchange for rice. The FB and experimental diets were analyzed for proximate constituents. Diets were then fed to twelve Beagle dogs in a replicated 4 x 4 Latin square design. Dogs were adapted to food for 9 days, and feces were collected for 5 days, then (d14) blood was collected by brachial venipuncture into vacuum tubes. Feces were scored on a scale from 1 to 5 (1=runny; 5= very hard feces). Fecal output was estimated using chromic oxide to determine digestibility. Blood was analyzed for complete blood count (CBC) and chemistry profile. The experiment was approved by the KSU IACUC. Means were separated by multivariate analysis of variance (MANOVA) by the GLM procedure (SAS, v 9.4). There were no differences among treatments for dietary intake, fecal output, and stool score. Apparent total tract digestibility (ATTD) of DM was highest (P<0.05) for FB0 (89.3%), intermediate for FB20 (88.9%), and slightly lower for dogs fed FB10 and FB30 (average 88.1%). Organic matter ATTD differed (P<0.05) for each treatment: with FB0>FB20>FB10>FB30 (92.7, 92.2, 91.7 and 91.4%, respectively). Gross energy ATTD was greater (P<0.05) for FB0, FB10 and FB20 (average 83.4%) than FB30 treatment (82.6%). Crude protein ATTD was greater (P<0.05) for FB0 and FB20 (average 90.7%) than for dogs fed FB10 and FB30 (average 89.8%). Crude fat ATTD was greater (P<0.05) for FB20 (95.2%), intermediate for FB0 and FB30 (average 94.0%), and for dogs fed FB10 it was lowest and similar to FB30 (93.5%). No differences were noted among treatments for CBC or chemistry profile and all values were within normal range for adult medium sized dogs. Palatability was slightly lower for total volume, intake ratio, and first choice for dogs fed the FB10 and FB30 relative to control. However, palatability measures for dogs fed the FB20 did not differ from that of dogs fed the control. This study suggests that FB is an effective ingredient for use in a commercial dog diet.