Effect of age, protein source and carbohydrate type on fecal microbiota, fecal fermentation products, intestinal mucosae histology and imunological paramethers of dogs

Abstract

The dog population have shown in the last years increased life expectance. Due the important relationship between dietary carbohydrates and proteins, gut microbiota and fermentation products, intestinal immunity and systemic immunity, this area have been received attention. No publication in this area for old dogs was found in literature, but is possible to suppose that manipulating gut microbial population and fermentation products, an ameliorating on dog immunosenescence could be achieved. The effects of age and protein and carbohydrate sources on gut microbial counts, fermentation products formation, food digestibility, gut mucosa histology, and some immune parameters of dogs will be studied. The experiment will follow a 3x2 factorial arrangement of treatments, with 3 diets and 2 ages, adding up six experimental treatments. Three blocks with 12 dogs each will be used, with six adult dogs (4 to 6 years old) and six old dogs (>12 years old), and two repetitions per treatment in each block, totalizing six repetitions (dog) per treatment. Three experimental diets will be used: a control diet based on corn and poultry by-product meal, with non fermentable fiber (sugarcane fiber); a diet with 30% of soybean meal (replacing poultry by-product meal); a diet with 10,5% of beet pulb (a source of fermentable fiber). Each block will follow: days 1 to 10 - diet adaptation; 11 to 15 - total fecal collection for digestibility evaluation; days 16, 17 and 18 - fresh fecal collection for pH, fermentation products (ammonia, pH, lactate, acetate, propionate, butirate, branched-chain fatty acids, indol, phenol, and biogenic amines); day 28 - fresh fecal collection for bacterial enumeration and IgA determination; day 29 - blood collection for immunophenotyping evaluation; days 30-31 for mucosae sampling through endoscopy and colonoscopy. Data will be evaluated using the GLM procedure of SAS Software, considering the effects of animal, block, treatment and they interactions. Means will be compared by the Tukey test (P<0.05). (AU)