Enzyme complex at different levels in diets with enriched ingredients for commercial laying hens
Revista Brasileira de Zootecnia
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,
... eonine, 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 (DM AM ), crude protein (CP AM ), gross energy (GE AM ), and phosphorus (P AM ); digestible crude protein (CP D ); and intake, retention, and excretion of phosphorus. No effects of EC levels were detected on the metabolizable energy values or digestibility coefficients, except for CP AM , which showed a quadratic response (maximum coefficient at 89.0 mg.kg -1 EC). A quadratic effect was also observed for CP D (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. which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Silva et al. 7 enzyme supplementation significantly increased the retention of protein and calcium (P<0.05) but had a negative effect (P<0.05) on the retention of phosphorus. According to Wang et al. (2006) , the use of enzymes improves the utilization of feedstuffs, thereby allowing for a reduction in the inclusion of certain nutrients, e.g., amino acids and minerals. This fact could be demonstrated in the present study, in which no alteration occurred in phosphorus intake, although an increase in the enzyme-complex levels raised the retention and excretion of that mineral. Conclusions The use of an enzyme complex containing pectinase, cellulase, phytase, β-glucanase, xylanase, protease, and amylase in corn-and soybean meal-based diets for layers improves their ileal digestibility of protein and apparent digestibility of phosphorus. However, the addition of that complex to the diets does not have any effect on apparent metabolizable energy, nitrogen-corrected apparent metabolizable energy, or its metabolizability coefficients.