Apparent total tract digestibility, fecal characteristics, and blood parameters of healthy adult dogs fed high-fat diets

Pet foods may be formulated with decreased starch to meet consumer demands for less processed diets. Fats and oils may be added to low-starch diets to meet energy requirements, but little is known about its effects on canine health. The study objective was to evaluate the effects of feeding healthy adult dogs low carbohydrate, high-fat diets on apparent total tract digestibility, fecal characteristics, and overall health status. Eight adult Beagles were enrolled in a replicated 4 x 4 Latin Square design feeding trial. Dogs were randomly assigned to one of four dietary fat level treatments (T) within each period: 32% (T1), 37% (T2), 42% (T3), and 47% (T4) fat on a dry matter basis. Fat levels were adjusted with the inclusion of canola oil added to a commercial diet. Each dog was fed to exceed its energy requirement based on NRC (2006). Blood samples were analyzed for complete blood counts, chemistry profiles, and canine pancreatic lipase immunoreactivity levels. Apparent total tract digestibility improved (P < 0.05) as the fat level increased for dry matter, organic matter, fat, and gross energy. Fecal output decreased as levels of fat increased in the diet (P = 0.002). There was no effect of fat level on stool quality or short-chain fatty acid and ammonia concentrations in fecal samples (P >= 0.20). Blood urea nitrogen levels decreased with increased fat level (P = 0.035). No significant differences were seen in canine pancreatic lipase immunoreactivity (P = 0.110). All blood parameters remained within normal reference intervals. In summary, increased dietary fat improved apparent total tract digestibility, did not alter fecal characteristics, and maintained the health status of all dogs.