Source of dietary fiber fed to dogs affects nitrogen and energy metabolismand intestinal microflora populations

Twenty-eight adult ovariohysterectomized dogs were fed one of four diets di ffering in type of dietary fiber to assess the effects of fiber on energy d igestibility, partitioning of nitrogen (N) components, and changes in intes tinal microflora. Dietary fiber sources were beet pulp (BP), short-chain fr uctooligosaccharides (FOS), cellulose (C) and a fiber blend (FB; BP, gum ta lha, and FOS). Dry matter (DM) intake was reduced and DM digestibility was increased for dogs fed the FOS diet. Fecal N and microbial N excretion (g/d ay) was greater with the FB diet. This diet tended to reduce urinary N excr etion. Bacterial characterization of intestinal contents found that FOS inc reased total aerobic bacteria in the distal colon. Fiber Blend decreased co unts of Clostridium spp. in the ileum. We concluded that fermentable fiber sources increase microbial growth in the colon, and have the potential to t rap and remove N from the body. (C) 2000 Elsevier Science Inc.