199 Effects of Dietary Fiber and Biotic Supplementation on Apparent Total Tract Macronutrient Digestibility, Fecal Characteristics, and Fecal Metabolites of Healthy Adult Dogs

Abstract

Abstract Synbiotics, or mixtures of live microorganisms and substrates selectively utilized by host microorganisms, may confer complementary or synergistic health benefits to the host. Although synbiotics have demonstrated the potential to modulate the gut microbiome and improve gastrointestinal health in many host species, research trials in companion animal diets are limited. Therefore, this study was conducted to determine the apparent total tract macronutrient digestibility (ATTD) of diets supplemented with fibers or biotics and to evaluate their effects on the fecal characteristics, metabolites, microbiota, and immunoglobulin (Ig) A concentrations of dogs consuming them. Healthy adult female beagles (n = 12; age= 6.2 ± 1.6 yr; BW = 9.5 ± 1.1 kg) were used in a replicated 3 x 3 Latin square design to test three dietary treatments: 1) basal diet based on rice, chicken meal, tapioca starch, and cellulose and without probiotics or prebiotics + a placebo treat (control, CT); 2) diet based on rice, chicken meal, garbanzo beans, and cellulose + placebo treat (GB); 3) diet based on rice, chicken meal, and garbanzo beans, and functional fiber/prebiotic blend (mannanoligosaccharides; fructooligosaccharides, inulin, pea fiber, alfalfa meal, Saccharomyces cerevisiae fermentation product) + probiotic-containing treat (synbiotic treatment, SYN). The probiotic treat contained Bacillus subtilus and Bacillus amyloliquefaciens (2 x 109 CFU/d). In each 28-day period, a 22-day diet adaptation was followed by a 5-day fecal collection phase for measurement of ATTD and fecal characteristics, metabolites, microbiota, and IgA concentrations. Fasted blood samples were collected on day 28 for serum chemistry and complete blood count. All data were analyzed using the Mixed Models procedure of SAS 9.4, with P < 0.05 being significant. ATTD of dry matter (DM), organic matter, and energy were less and DM fecal output was greater in dogs fed SYN than those fed CT or GB, whereas ATTD of crude protein was greater in dogs fed CT and SYN than those fed GB. ATTD of fat was higher and wet fecal output was less in dogs fed CT than those fed GB or SYN. Fecal DM% was greater in dogs fed CT than those fed SYN or GB, and greater in dogs fed SYN than those fed GB. Fecal short-chain fatty acids (SCFA; acetate, propionate, total SCFA) were higher in dogs fed GB than those fed CT or SYN, and higher in dogs fed GB than those fed SYN. Fecal IgA concentrations were greater in dogs fed GB than those fed CT. Serum triglycerides were less in dogs fed GB than those fed SYN or CT. Our results demonstrate that legume-based dietary fibers, with or without prebiotics and probiotics, slightly reduce nutrient digestibility, increase stool output, beneficially shift fecal metabolites, and reduce blood lipids of adult dogs.