Abstract The aim of this study was to perform a comparative analysis of table egg quality in relation to the genotype and age of laying hens. A total of 180 eggs were analysed, comprising 30 eggs from Lohmann Brown hens and 30 eggs from Lohmann LSL hens at 25, 50, and 72 weeks of age. Morphometric traits (egg weight, length, width, and shape index), shell characteristics (eggshell surface area, shell thickness, and shell strength), and quantitative traits of egg components (percentage of shell, albumen, and yolk; thick albumen height; Haugh units; and yolk colour parameters L*, a*,b* and Roche score) were evaluated. In addition, feed conversion ratio, egg production rate, and total egg number per hen were recorded throughout the laying period. The results showed a significant effect of hen genotype on egg weight (Lohmann Brown: 64.70 g vs. Lohmann LSL: 59.97 g), egg length and width, egg shape index, eggshell surface area and strength, albumen proportion (65.09 vs. 63.23%), yolk proportion (24.90 vs. 26.72%), thick albumen height, Roche score, Haugh units, and yolk b* colour. Hen age significantly affected egg weight (25 weeks: 56.77 g vs. 72 weeks: 66.20 g), egg width and length, the proportion of shell, albumen (25 weeks: 65.71% vs. 50 weeks: 62.71%), and yolk, eggshell surface area (25 weeks: 70.08 cm² vs. 72 weeks: 77.58 cm²), as well as yolk colour parameters L* and a*. Significant genotype × age interactions were observed for egg weight and width, egg shape index, and also eggshell surface area and strength, Haugh units, and yolk colour parameters a* and b*.
Wegner et al. (Sun,) studied this question.