Influence of Xylanase Inclusion on Productive Performance, Egg Quality and Intestinal Health of Commercial Laying Hens Fed Energy-Reduced Diets.

This study evaluated the inclusion of increasing levels of xylanase in reduced-energy diets for commercial laying hens. A total of 280 Lohmann LSL white laying hens were equally allocated one of five dietary treatments, with seven replicates of eight hens each being a positive control: a wheat and soybean meal-based diet (PC, ME 2725 kcal/kg), a negative control diet (NC, PC minus 100 kcal) and three diets with increasing xylanase levels of 50, 100 and 150 g/MT (NC + XM50, NC + XM100 and NC + XM150, respectively). The hens were monitored from 20 to 40 weeks of age to assess productive performance, egg quality and intestinal health, including histomorphometry, permeability and microbiota composition. Xylanase inclusion at 50 and 100 g/MT significantly improved egg production and egg mass, as well as shell strength and thickness, while maintaining feed intake and feed conversion efficiency, while xylanase inclusion at 150 g/MT decreased egg production and egg mass. Additionally, intestinal permeability was significantly reduced, and positive changes were observed in the gut microbiota. Higher doses of xylanase (100 and 150 g/MT) increased bacterial abundance and diversity, with a greater presence of beneficial phyla such as