Comparative Analysis of Nutrient Digestibility and Nitrogen Retention in Wild and Farmed Canids

The aim of this study, conducted in November 2012, was to determine whether farming of common foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) leads to changes in nutrient digestibility and nitrogen retention in comparison with their wild counterparts. Wild and farmed animals were compared within and between species. Each group consisted of five males and five females aged around eight months. Farmed silver foxes - a variety of the common red fox (group FSF) and farmed raccoon dogs (group FRD) were purchased from a breeding farm in southeastern Poland. Wild red foxes (group WRF) and wild raccoon dogs (group WRD) were trapped in the hunting grounds of the Polish Hunting Association (Olsztyn Division). The animals were placed in metabolism cages. The coefficients of nutrient and energy digestibility, and daily nitrogen balance and retention values were compared between groups. Farmed animals tended to have higher digestibility coefficients than their wild counterparts. No significant differences were noted within species. The coefficients of dry matter (P≤0.01), organic matter (P≤0.05, P≤0.05) and protein (only FSF vs. WRD - P≤0.05) digestibility were higher in foxes. Raccoon dogs were characterized by higher digestibility of carbohydrates - N-free extracts (P≤0.01). Nitrogen retention was higher in farmed animals. The highest and lowest levels of retained nitrogen were observed in groups FSF and WRD, respectively