Enzyme complex at different levels in diets with enriched ingredients for commercial laying hens

The objective of this study was to evaluate levels of inclusion of an enzyme complex (EC) in corn- and soybean meal-based diets for laying hens on the digestibility of nutrients and energy. A metabolism trial was conducted using 75 Dekalb Brown laying hens at 26 weeks of age, which were distributed into five treatments with five replicates in a completely randomized design. The ingredients used in the diets received an additional (enriched) 3% methionine, lysine, cysteine, threonine, tryptophan, and metabolizable energy and 33.3% phosphorus. Treatments consisted of diets including 0, 150, 200, 250, or 300 mg.kg(-1) EC. We determined apparent metabolizable energy (AME); nitrogen-corrected AME (AMEn); apparent metabolizability coefficients of dry matter (DMAM), crude protein (CPAM), gross energy (GE(AM)), and phosphorus (P-AM); digestible crude protein (CPD); and intake, retention, and excretion of phosphorus. No effects of EC levels were detected on the metabolizable energy values or digestibility coefficients, except for CPAM, which showed a quadratic response (maximum coefficient at 89.0 mg.kg(-1) EC). A quadratic effect was also observed for CPD (minimum at 115 mg.kg(-1) EC), P excretion (maximum at 173.2 mg.kg(-1) EC), and P retention (maximum at 122.4 mg.kg(-1) EC) when EC was used. The use of the EC in corn- and soybean meal-based diets for laying hens improves their ileal digestibility of protein and apparent digestibility of phosphorus. However, EC addition to the diets does not affect AME, AMEn, or their metabolizability coefficients.