Abstract
A 15-week trial examined the effects of dietary enzyme supplementation on egg production, egg mass, egg composition, and nutrient retention in layers (Hy-Line W-36) fed diets containing wheat middlings (WM) from 25 to 40 weeks of age. The enzymes used were a commercially available combination of xylanase, amylase and protease. Seven diets were assigned to five replicate cages with five hens per pen. Diet 1 was a corn-soy control; diets 2, 4, and 6 contained 10, 20 and 30% levels of WM, respectively, while diets 3, 5 and 7 contained these same levels, respectively, but supplemented with 0.1% enzyme. Feed intake and egg production were not significantly affected by treatment. Hens fed the control diet had significantly better feed conversion ratio (FCR) than those fed the WM diets (1.84 versus 1.95, respectively). Enzyme supplementation had no effect on egg production, but had a significant (P < 0.001) effect on egg mass. Excreta crude protein retention was higher for the control diet (53.4 versus 46.0% for the WM diets). Enzyme increased significantly excreta calcium retention (54.6 versus 46.0%, respectively). Enzyme improved apparent metabolisable energy values compared to diets without enzyme supplementation (2,980 versus 2,898 kcal kg
−1
). Type of diet had the most significant effect on performance. Including WM in laying hen diets depend on the price of corn and could serve as a good alternative. Enzyme supplementation to WM diets improved apparent nutrient digestibility but had no effect on feed conversion nor egg mass.