Effect of protease supplementation on production performance of laying hens

The experiment was conducted with the objective of evaluating the effect of protease enzyme supplementation on performance parameters and quality shell of laying hens. We used 240 Isa Brown commercial laying hens with 44 weeks of age. A completely randomized split-plot design (5 periods of 21 days) with four treatments and six replications (10 hens per replication) was used. The experimental diets were formulated according to the requirements of the breed. The following parameters were evaluated: egg production, feed intake, feed conversion, average egg weight, egg loss, specific gravity, percentage and shell thickness. After collection, the data were analyzed with SISVAR Statistical Package, and the means compared by SNK test at 5% probability. It was concluded that supplementation of diets low in nutrients with 500 g ton-1 of protease (100 U g-1), provides egg production and feed conversion rates similar to those obtained in laying hens fed diet with the nutritional level recommended for the breed. However, protease supplementation did not show effect on egg shell quality.

本试验旨在评估蛋白酶（protease）添加对蛋鸡生产性能参数及蛋壳品质的影响。试验选用240只44周龄的伊莎褐（Isa Brown）商品蛋鸡。试验采用完全随机裂区设计，设置5个21天的试验周期，共设置4个处理组与6个重复组（每个重复组饲养10只蛋鸡）。试验日粮按照该品种的营养需求进行配制。本次试验测定的指标包括：产蛋率、采食量、饲料转化率、平均蛋重、破蛋率、蛋比重、蛋壳百分比及蛋壳厚度。数据采集完成后，采用SISVAR统计分析软件包进行统计分析，组间均值比较采用SNK检验，显著性水平设定为5%。试验结果表明，在低营养水平日粮中添加500 g·ton⁻¹（100 U·g⁻¹）的蛋白酶，可使蛋鸡的产蛋率与饲料转化率达到与饲喂符合品种推荐营养水平日粮的蛋鸡相近的水平。但蛋白酶添加对蛋壳品质无显著影响。