Nutrient Digestibility of a Vegetarian Diet with or without the Supplementation of Feather Meal and Either Corn Meal, Fermented Rye or Rye and Its Effect on Fecal Quality in Dogs

SIMPLE SUMMARY: There is a particular need to find components for more sustainability in dog foods. Rye can be produced with a very low environmental impact among cereals. Animal products like hydrolyzed feather meal cannot be used for human consumption. The aim of the present study was to evaluate the offering of a vegetarian diet supplemented with or without feather meal and either corn meal, fermented rye or rye on the fecal quality and the digestibility of nutrients in dogs. Thus, eight Beagle dogs (11.0 ± 1.31 kg) with a median age of three years were included for this study. The dogs received a vegetarian basic diet containing wheat, broken rice and rice protein or the same diet supplemented with hydrolyzed feather meal (2.7%) and either 20.1% of corn meal, 60.4% of fermented rye or 20.1% of rye as is basis (moisture content of the diets about 42%). During the study, the feces were well formed and firm and the digestibility of the diet was not different by using rye compared to all other diets. Moreover, the acceptance “food intake scoring“ was similar among the experimental diets fed to dogs. Therefore, rye can be considered as an alternative cereal grain in dog foods. ABSTRACT: Cereals with low environmental input like rye and animal by-products which cannot be used for human food like feather meal are receiving growing interest as sustainable feed sources. Thus, eight Beagle dogs were included in a 4 × 4 Latin Square design and received a vegetarian basic diet or the same diets supplemented with hydrolyzed feather meal (2.7%) and either 20.1% of corn meal, 60.4% of fermented rye or 20.1% of rye as is basis (moisture content of the diets about 42%). Compared to other groups the dry matter (DM) content of feces from dogs fed the basic diet was higher (30.0%, p < 0.05), while dogs fed the basic diet + rye had the lowest DM-content (26.5%, p < 0.05). However, the fecal scores were considered to be within an acceptable range (well-formed and firm). Starch digestibility was lower (p < 0.05) for dogs fed the basic diet + corn meal. The dogs showed a high and identical acceptance (scoring of food intake) of the experimental diets. As a comparable quality of feces and a high nutrient digestibility were observed when rye was used in the experimental diets—it can be considered an alternative carbohydrate source in dog foods.