Production Performance and Egg Quality of Laying Hens as Influenced by Genotype and Rearing System

ABSTRACT The aim of this study was to evaluate the effect of rearing systems and genotypes on production performance and egg quality. Isa Brown and New Hampshire genotypes were used in this study. These two genotypes were housed in floor and organic rearing systems. During the experimental period, which lasted one year (52 weeks), the following production performance parameters were recorded: egg production, daily egg mass, feed consumption, feed conversion efficiency, and mortality. Fifteen eggs per group were collected for analysis at 64 weeks of hen age. These samples were evaluated for external parameters (egg weight and egg shape index), internal parameters (albumen height, Haugh unit, and the proportions of albumen, yolk and shell), eggshell quality parameters (shell thickness, shell deformation and shell breaking strength), and eggs’ chemical composition (dry matter, minerals, protein and lipids). Generally, Isa Brown hens had better production performance than New Hampshire hens. At the same time, organic New Hampshire layers performed better than floor-reared ones. Genotype had a significant effect on all ten egg quality parameters (external, internal and eggshell quality), rearing system independently affected only egg weight, and the interaction of the observed factors significantly influenced seven parameters. Genotype had a significant effect on three of the four chemical composition parameters, while no significant effect of the rearing system was established on the chemical composition of eggs. The rearing system x genotype interaction significantly affected the eggs’ protein content.

摘要 本研究旨在评估饲养系统与品系对家禽生产性能及蛋品质的影响。本试验选用伊莎褐（Isa Brown）与新汉夏（New Hampshire）两个品系，分别采用地面饲养与有机饲养两种模式。试验周期为1年（52周），期间记录的生产性能指标包括产蛋量、日均蛋重、采食量、饲料转化率及死亡率。在母鸡64周龄时，每组采集15枚鸡蛋用于品质分析，检测指标涵盖外部品质指标（蛋重、蛋形指数）、内部品质指标（蛋白高度、哈氏单位（Haugh unit）以及蛋清、蛋黄、蛋壳占比）、蛋壳品质指标（蛋壳厚度、蛋壳变形度、蛋壳抗破强度），以及鸡蛋化学成分（干物质、矿物质、蛋白质与脂类）。总体而言，伊莎褐鸡的生产性能整体优于新汉夏鸡；同时，采用有机饲养的新汉夏蛋鸡生产性能优于地面饲养的个体。品系对全部10项蛋品质指标（外部、内部及蛋壳品质）均有显著影响；饲养系统仅对蛋重产生独立影响；二者的交互作用对7项指标存在显著影响。品系对4项化学成分指标中的3项具有显著作用，而饲养系统对鸡蛋化学成分无显著影响。饲养系统与品系的交互作用仅对鸡蛋蛋白质含量存在显著影响。