Abstract
The experiment was conducted to estimate the matrix value of xylanase and the effect of dietary xylanase supplementation on growth performance, viscosity, digestibility, and carcass traits in broiler chickens. A total of 588 one-day-old Ross 308 broiler chicks were raised with a commercial diet until day 7 and seven-day-old chicks were randomly allotted to one of seven dietary treatments with twelve replicates. Diets were corn-soybean meat based with wheat added. Dietary treatments were as follows; four basal diets (PC, energy sufficient diet; NC-1, -40 kcal/kg ME reduced from PC diet; NC-2, -80 kcal/kg ME reduced from PC diet; NC-3, -120 kcal/kg ME reduced from PC diet) and three different xylanase activity levels diet (NCX-1, 1,500 U/kg xylanase activity; NCX-2, 3,000 U/kg xylanase activity, NCX-3 4,500 U/kg xylanase activity) in the NC-3 diet. The standard xylanase dose was decided from the previous in vitro experiment. The weight gain and feed intake were measured and feed efficiency was calculated weekly. One bird per pen was selected and euthanized to harvest the intestinal digesta, breast meat, and leg meat samples on days 24 and 35. The linear and quadratic regression analysis and regression plateau were used to determine the xylanase recommendation and marginal level. The viscosity, digestibility, and proximate analysis of meat were analyzed from taken samples. Xylanase-added treatments were performed for higher (p < 0.05) body weight and body weight gain. Furthermore, xylanase-added treatments showed higher protein digestibility and lower viscosity compared to non-xylanase treatment. The maximum metabolizable energy compensation level of xylanase calculated by the regression was 120 kcal/kg and the marginal xylanase level showed maximum performances were 3,622 U/kg on the linear plateau and 4,000 U/kg on the quadratic plateau. Therefore, our experiment suggested that xylanase addition in an energy deficiency diet not only enhances growth performance but also reduces viscosity, and enhances protein digestibility and the maximum compensation level of metabolizable energy was 120 kcal/kg. The recommended levels of xylanase supplementation were determined to be 3,622 and 4,000 U/kg.