The objective of the study was to evaluate the quality of eggs laid by native breed hens of different ages (33 and 53 weeks of age), with particular consideration of the lysozyme parameters. Eggs were collected from 6 breeds/strains of laying hens under the genetic resources conservation in Poland, i.e. Greenleg Partridge (Z-11), Yellowleg Partridge (Ż-33), Rhode Island Red (R-11), Rhode Island White (A-33), Sussex (S-66) and Leghorn (H-22). The yolks of eggs from older hens had a more favourable, intense colour, but the freshness parameters (albumen height and Haugh units) of these eggs were lower. The albumen of eggs from older hens showed greater content and higher enzymatic activity of lysozyme in both thin and thick albumen. Among the six strains of hens, lysozyme content and enzymatic activity were highest in the egg albumen of strains Ż-33, Z-11 and R-11, and lowest in that of strain H-22. The analysed eggs showed statistically significant correlations between some interior egg quality traits (albumen weight, albumen height, Haugh units, yolk colour) and the discussed enzyme parameters. These traits are influenced by genotype and age of the hens.

中文翻译：

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蛋鸡基因型，年龄和一些内部蛋品质性状对溶菌酶含量的影响

该研究的目的是评估不同年龄（33和53周龄）的本地种母鸡产下的鸡蛋的质量，并特别考虑溶菌酶参数。在波兰的遗传资源保护下，从6个品种/品系的蛋鸡中收集了鸡蛋，即绿腿Green（Z-11），黄腿Part（Ż-33），罗德岛红（R-11），罗德岛白（A） -33），苏塞克斯（S-66）和来克亨（H-22）。年龄较大的母鸡的蛋黄色更佳，颜色更深，但这些蛋的新鲜度参数（白蛋白高度和霍夫单位）较低。年龄较大的母鸡的卵蛋白在稀蛋白和稠蛋白中均显示出更高的含量和更高的溶菌酶酶活性。在六种母鸡中，,-33菌株的蛋清中溶菌酶含量和酶活性最高，Z-11和R-11，在H-22菌株中最低。分析的鸡蛋在某些内部鸡蛋品质性状（白蛋白重量，蛋白高度，Haugh单位，蛋黄颜色）和所讨论的酶参数之间显示出统计学上显着的相关性。这些性状受母鸡的基因型和年龄的影响。