Xylanases in diets with alternative feeds and energy reduction in commercial layers

The use of alternative ingredients has been increasing in a continuing attempt to reduce production costs, along with the use of additives, such as carbohydrases, for their possible positive effects on nutrient metabolization by layers. Thus, this study aimed to evaluate the effects of different xylanases in diets with reduced metabolizable energy (ME) and the inclusion of alternative ingredients on the metabolizability of nutrients in diets for commercial laying hens, by conducting two metabolism tests. In the first trial,100 layers hens were distributed in a fully randomized 2 × 2 + 1 factorial design (two metabolizable energy reductions × two xylanases, plus one control diet). In the second assay,140 layer hens were distributed in a fully randomized 2 × 3 + 2 factor design (two xylanases× three ingredients, plus two control diets, positive and negative). It was concluded that supplementation with pantanal xylanase improved the metabolizability of nutrients in corn-based diets and soybean meal for light commercial layers, allowing for a reduction of up to 200 kcal/kg of ME in the diets. Xylanases are more effective on wheat bran enabling a decrease of 150 kcal/kg of ME in commercial laying diets without affecting nutrient metabolizability. The action of pantanal xylanase in diets containing fibrous ingredients was similar to that of commercial xylanase.