Effect of xylanase supplementation on diet digestibility and fermentation products of dogs fed whole and defatted corn germ

ABSTRACT The objective of this study was to evaluate the coefficients of total tract apparent digestibility (CTTAD) of nutrients, fecal characteristics, intestinal fermentation products, and diet palatability in dogs fed xylanase-supplemented diets with inclusion of whole or defatted corn germ in two experiments. Experiment I - six adult dogs were distributed in a 6 × 6 Latin square in a 3 × 2 factorial scheme with the experimental diets: control, without the addition of germ (CO−); CO plus xylanase (CO+); 200 g kg−1 inclusion of whole corn germ (WG−); WG plus xylanase (WG+); 200 g kg−1 inclusion of defatted corn germ (DG−); and DG plus xylanase (DG+). Experiment II - the palatability test was performed in pairs: CO vs. 200 g kg−1 WG, CO vs. 200 g kg−1 DG, and 200 g kg−1 WG vs. 200 g kg−1 DG. Xylanase addition, compared with enzyme-free, led to greater CTTAD of dry matter (0.807 × 0.787), crude protein (0.849 × 0.828), and gross energy (0.838 × 0.820) (P<0.05). An interaction showed that xylanase increased metabolizable energy in DG diet (P<0.05). Germ inclusion resulted in higher fecal dry matter compared with CO (407.4 × 377.3; P<0.05). The DG diet reduced propionic concentration and total short-chain fatty acids compared with WG and CO (P<0.05). There was a preference of WG over CO both in the first choice and intake (P<0.05). Xylanase supplementation improves nutrient digestibility and GE in dog fed diets containing whole or defatted corn germ, while not affecting fecal characteristics and intestinal fermentation products. The use of WG has a positive effect on diet palatability.