Four wheat-based diets with either a low soluble content of non-starch polysaccharides (NSPs, 13 g/kg); low viscosity, LV) or a high content of NSPs (33.5 g/kg; high viscosity, HV), with and without exogenous xylanase (XYL), were fed to male Ross 308 broiler chickens from 7 to 21 days age. The enzyme was supplemented at 100 FXU/kg diet, and its preparation was based on endo-1,4-beta-xylanase produced by Aspergillus oryzae. Each diet was fed to eight pens, with five birds in each pen, following randomisation. Chicks fed XYL had an improved feed efficiency, hepatic coenzyme Q10, caecal butyric acid concentration, nitrogen digestibility (p p p < 0.05), but no differences were observed on nutrient digestibility and growth performance variables. This also suggests that birds may tolerate a greater dietary NSPs content; thus, further benefits may be obtained by the application of XYL in low energy wheat-based diets.
