Document Type : Original Article


Department of Poultry Nutrition, Animal Production Research Institute, ARC, Dokki, Giza-12618, Egypt


This experiment was conducted to study the ability of supplemental xylanase enzyme (Xyl) to improve growth performance, carcass traits, meat quality and feeding cost of broilers fed on low metabolizable energy (ME) corn-soybean meal diets. Two hundred and forty, one day old unsexed Arbor Acres broiler chicks were randomly distributed into six treatments (2x3 factorial design) each had four replicates. Chicks were fed on corn-soybean diet supplemented with two levels of Xyl (0 and16000 U/kg of diet), and three ME levels which were standard strain recommendation (STD), 100 kcal lower than STD (E100) and 150 kcal lower than STD (E150) of each feeding phase for STD, E100, and E150 levels, respectively. The dietary ME values were 3000, 2900 and 2850  kcal/kg diet at starter phase; 3100, 3000 and 2950 kcal /kg at grower phase; and 3200, 3100 and 3050 kcal/kg at the finisher phase. All diets were formulated to save the strain requirements from the rest of nutrients. All chicks were housed in open system broiler house and received the same managerial conditions and veterinary program during experimental period (1-40 d of age). Parameters of growth performance, carcass characteristics, physical and chemical evaluation of broiler meat were carried out and feeding cost was calculated. The recorded results showed that xylanase supplementation to broiler diets resulted in significant improvement of body weight, body weight gain, feed conversion ratio, dressing %, and breast meat yield %, while feed intake and ultimate pH (pHu) of both breast and thigh cuts  were decreased. Regarding to ME of diets, reducing ME values from STD level to E150 level caused significant reduction in final body weight, abdominal fat %, pHu of breast meat samples and concentrations of malondialdehyde (MDA) and low density lipoprotein (LDL). Furthermore this reduction of ME levels caused significant increase of feed intake, % of drum stick and concentration of total protein of broiler meat at 40 d of age. Among experimental treatments chicks of both STD+Xyl and E100+Xyl treatments showed better growth performance, carcass traits, and meat quality compared with other treatments. In addition applying these treatments resulted in saving 9.25 % and 3.51% from feeding cost/kg of body weight relative to feeding cost of STD group. According to these results it could be concluded that adding xylanase enzyme to either STD or E100 corn-soybean meal broiler diets could enhance the quality of produced broiler accompanied with saving in feeding cost.


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