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

ABSTRACT 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 (GEAM), and phosphorus (PAM); 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‒1EC). 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.

摘要 本研究旨在评估复合酶制剂（enzyme complex, EC）在玉米-豆粕型产蛋鸡日粮中的添加水平对养分及能量消化率的影响。本试验选取75只26周龄的迪卡褐壳产蛋鸡，采用完全随机试验设计，分为5个处理组，每组设置5个重复。试验所用日粮的基础原料额外强化了3%的蛋氨酸、赖氨酸、半胱氨酸、苏氨酸、色氨酸与代谢能，同时添加33.3%的磷。各处理组日粮分别添加0、150、200、250或300 mg·kg⁻¹的复合酶制剂。本试验测定的指标包括：表观代谢能（apparent metabolizable energy, AME）、氮校正表观代谢能（nitrogen-corrected AME, AMEn）、干物质表观代谢率（dry matter apparent metabolizability coefficient, DMAM）、粗蛋白质表观代谢率（crude protein apparent metabolizability coefficient, CPAM）、总能表观代谢率（gross energy apparent metabolizability coefficient, GEAM）、磷表观代谢率（phosphorus apparent metabolizability coefficient, PAM）、可消化粗蛋白质（digestible crude protein, CPD），以及磷的摄入量、保留量与排泄量。结果显示，复合酶制剂的添加水平对代谢能值及多数养分表观代谢率均无显著影响，仅粗蛋白质表观代谢率呈现二次曲线响应，其最大值出现在89.0 mg·kg⁻¹的添加水平下。此外，可消化粗蛋白质、磷排泄量与磷保留量同样呈现二次曲线效应：可消化粗蛋白质的最小值出现在115 mg·kg⁻¹添加水平，磷排泄量的最大值出现在173.2 mg·kg⁻¹添加水平，磷保留量的最大值出现在122.4 mg·kg⁻¹添加水平。在产蛋鸡玉米-豆粕型日粮中添加复合酶制剂，可提升其回肠蛋白质消化率与磷的表观消化率，但对表观代谢能、氮校正表观代谢能及各养分表观代谢率无显著影响。