Effects of Xylanase and Protease Supplementation on Growth Performance, Meat Quality, Gut Health, Cecal Fermentation, and Bone Traits in Broiler Chickens

This study investigated the effects of dietary xylanase and protease supplementation, applied individually or in combination, on growth performance, intestinal characteristics, gut fermentation, meat quality, and skeletal traits in broiler chickens. A total of 540-day-old male broiler chicks were allocated to six experimental groups and fed a control corn-soybean meal-based diet or diets supplemented with xylanase, protease, or a xylanase–protease combination. Enzyme supplementation significantly improved body weight gain and feed efficiency, particularly between days 22 and 42, and reduced intestinal digesta viscosity. Improvements in gut morphology were reflected by increased villus height and villus-to-crypt ratios, accompanied by higher cecal total volatile fatty acid concentrations, increased Lactobacillus populations, and reduced coliform counts. In contrast, breast meat physicochemical composition and antioxidant status were not affected by dietary treatments. Skeletal development was positively influenced, with improvements observed in selected morphometric and structural bone traits. Overall, dietary xylanase and protease supplementation enhanced broiler performance and skeletal development primarily through improved digestive efficiency and favorable modulation of gut morphology, microbial ecology, and intestinal fermentation, without adverse effects on meat quality.