Investigation of the Digestibility, Fecal Characteristics, and Palatability of Oil Mil By-Products as a Plant-Based Protein Source in Canine Diets

This study investigates the digestibility, fecal characteristics, and palatability of plant-based protein sources in canine diets. With an increasing number of pet owners adopting vegan lifestyles for ethical, health, and environmental reasons, the demand for plant-based dog diets has risen. Using plant by-products can also be a practical and sustainable option for feeding pets. This study included eight healthy female dogs fed four different plant-based diets using a Latin square (4 × 4) crossover design, with linseed press cake, sunflower press cake, pumpkin press cake, and soy press cake as protein sources. To measure the acceptance of the protein sources, a five-bowl test was used. The apparent total tract digestibility of the different diets and the fecal quality were compared as well as the acceptability of the individual protein sources. The results showed significantly (<i>p</i> < 0.0001) better acceptance for the pumpkin press cake compared to the other three tested press cakes, whereas the addition of potato flakes changed the acceptance and showed no significant (<i>p</i> = 0.1105) differences between the press cakes. Among the tested diets, the highest protein digestibility was observed for the pumpkin diet (85.11% ± 1.77%), followed by the sunflower (84.23% ± 2.20%) and soy diets (82.35% ± 3.37%), while the linseed diet showed the lowest protein digestibility (77.52% ± 6.04%).