Urooj Anwar¹, Attalla F. El-kott², Muhammad Qamar Bilal¹, Muhammad Riaz¹, Muhammad Farooq Khalid³, Riaz Mustafa³, Umar Farooq³, Muhammad Ashraf¹, Muhammad Farhan Ayaz Chisti¹ and Muhammad Aziz ur Rahman^1*

Current study was planned to evaluate supplementation of two different xylanase levels on digesta viscosity, blood metabolites and intestinal morphology of broiler chickens fed low energy wheat-based diet. A total of 480-day old broiler chicks were used in the current study with 8 replicates per treatment, and each replicate had ten birds. Six iso-caloric and iso-nitrogenous diets were prepared according to strain recommendations. Wheat was used in all dietary treatments except control treatment in which corn-soybean was used. Experimental diets were formulated as, 1) =control, corn-soybean based diet 2) = wheat-based diet, 100% wheat, no corn, 3) = 100% wheats, ME lowered 75 Kcal with 1000XU/kg of feed, 4) = 100% wheats, ME lowered 75 Kcal with 1500XU/kg of feed, 5) = 100% wheats, ME lowered 150 Kcal with 1000XU/kg of feed, 6) = 100% wheats, ME lowered 150 Kcal with 1500XU/kg of feed. Less viscosity, cholesterol and urea nitrogen noted in birds fed control diet and 100% wheat-based diet without xylanase supplementation (P<0.05). Low blood glucose was observed in diets without supplementation of xylanase and without reduced energy levels (P<0.05). Better villus height, villus width and villus surface area were in birds fed control diet and wheat-based diet with no lowered energy level and without xylanase supplementation (P>0.05). Based on the findings of current study, the inclusion of xylanase in diets with 75 Kcal lowered energy perform better than diets with 150 Kcal lowered energy.