| Abstract: | A trial was performed to examine the effects of levels of barley substitution and supplementation with β-glucanase in a corn-soybean diet on growth performance and intestinal characteristics of broiler chickens. The experiment involved five levels of barley substituted for corn (0, 125, 250, 500, and 1000 g/kg) and two levels of β-glucanase supplement (with 0.5 g/kg and without) in a factorial arrangement with two replicates. Four hundred day-old commercial strain Harber broiler chickens were randomly allocated into twenty groups of ten dietary treatments for a six-week feeding trial, growing (0-3 week) and finishing period (4-6 week). Unless supplemented with β-glucanase, broilers receiving the diet with more than 250 g/kg of the barley substitute gained slower during the growth period. Conversely, supplementing β-glucanase did not improve total weight gain (0-6 weeks) with a diet of 500 g/kg barley substitution. As the level of barley substitution increased, feed intake in the growing period decreased significantly and viscosity of the intestinal contents increased. However, such an increase did not significantly influence feed conversion (P > 0.05). Supplementation with β-glucanase on diet up to 250 g/kg of barley substitute not only enhanced body weight gains of growing broilers, but also improved the live-weight of six-week-old broilers (P < 0.05). |
