Addition of xylanase to high and low nutrient density diets on nutrient digestibility and palatability, fecal characteristics, fermentation products and intestinal permeability in dogs

Abstract

The objective of the study was to evaluate the effect of xylanase inclusion (80,000 birch xylanase units, BXU/kg of diet, as fed) in diets with high and low nutrient density on the coefficients of total tract apparent digestibility (CTTAD) of nutrients, dietary metabolizable energy (ME), fecal characteristics, fermentation products, and intestinal permeability of dogs. In addition, the palatability of the diet was evaluated. Four dietary treatments were applied: HD, high nutrient density without xylanase; HD+X, HD diet with xylanase; LD, low nutrient density without xylanase; LD+X, LD diet with xylanase. In experiment I, digestibility, fecal characteristics, fermentation products and intestinal permeability variables were measured in 12 adult Beagle dogs, distributed in a completely randomized design in a 2 × 2 factorial scheme. In experiment II, a palatability test was performed in pairs by means of two comparisons: HD vs. HD+X and LD vs. LD+X. The HD diet showed higher CTTAD compared to the LD diet (P < 0.05). The dietary inclusion of the enzyme showed no change in CTTAD of nutrients and ME (P > 0.05). There was an interaction between factors for the concentration of propionic, isovaleric and isobutyric acids (P < 0.05). Similarly, lower concentrations of putrescine and cadaverine were found in the feces of dogs fed HD+X diets (P < 0.05). The LD diet increased the intestinal permeability (P < 0.05), and palatability was not altered by the xylanase inclusion (P > 0.05). In conclusion, the addition of 0.5 g/kg xylanase does not affect nutrient digestibility and fecal characteristics of dogs fed low and high nutrient density diets. However, biogenic amine concentrations were reduced when adding xylanase to HD diets. Furthermore, LD diets lead to lower digestibility and increased intestinal permeability. Finally, the palatability is not affected by the inclusion of xylanase.