Effect of phytase and carbohydrases supplementation on digestibility, palatability, fecal characteristics and fecal fermentation products in dogs fed plant-protein diet

Abstract

The use of exogenous enzymes in canine nutrition has been studied as a way to improve the nutritional value of plant by-products. This study conducted 2 experiments to evaluate the effects of exogenous phytase and a complex of carbohydrases supplementation on plant protein based diets for dogs. Dietary treatments consisted of an animal protein-based diet (AD; poultry offal meal and meat-and-bone meal) without enzyme inclusion; a plant protein-based (PD; soybean meal) without enzymes, considered the control diet; PD + 5000 phytase units (FTU)/g (PD + P5); PD + 10,000 FTU/g (PD + P10); PD + 15,000 FTU/g (PD + P15); PD + 50,000 units of a carbohydrase enzyme complex (U)/g (PD + C); PD + a combination of 5000 phytase units FTU/g and 50,000 units of a carbohydrase complex U/g (PD + PC). In experiment 1, 14 dogs were fed the experimental diets and distributed in a randomized block design to assess digestibility, fecal characteristics, and fecal fermentation products. In experiment 2, a palatability test was evaluated in pairs by the means of two comparisons: PD vs. PD + PC and PD + P5 vs. PD + PC, with 16 dogs. The inclusion of PD + PC did not alter the digestibility of the diet (P > 0.05). The inclusion of phytase linearly increased fecal pH, concentrations of acetic and propionic acids, and total production of short-chain fatty acids (P < 0.05) in the feces of the dogs. Dogs fed the diet with enzyme complex (PD + PC) had a greater intake ratio when compared to the PD diet (P < 0.05). There was no difference (P > 0.05) in the first choice of the dogs for a specific diet for any of the comparisons made. Enzyme supplementation did not influence nutrient digestibility, but it increased the ME content of the PD. In addition, supplementation with the carbohydrase complex increased the production of total short-chain fatty acids and reduced fecal dry matter without compromising the acceptance of the diets.