The effect of the genetic origin of hens on selected egg traits.

Background: Eggs have been considered an important component of the human diet for centuries. There is currently a wide assortment of eggs available to consumers, varying in terms of weight (from S to XL), housing system (0 to 3), diet, packaging, etc. Although the egg’s nutritional value is most important to consumers, their perceptions are unfortunately generally based not on facts, but on popular opinion. Most commercial lines of laying hens used in Poland are of foreign origin. However, some farms use commercial lines from Polish breeding farms. Therefore, research was undertaken to determine selected characteristics of eggs obtained from hens of different origins raised in an intensive system, i.e. industrial production of eggs.

Methods: The research material consisted of eggs from Hy-Line Brown and Messa 43 hens from large-scale production. The eggs were obtained from hens at the ages of 35, 40 and 45 weeks. The analysis included selected external and internal characteristics of eggs laid during the study period. The eggs were evaluated immediately after laying, and the following quality parameters were determined: egg weight, shell weight, shell thickness, white weight, yolk weight, and pH of white and yolk. Chemical analysis of dry matter, total protein, crude fat and crude ash content in the whites and yolks was performed. The cholesterol content and fatty acid profile in the yolk were analysed as well. A statistical analysis of the results was performed.

Results: The analyses revealed significant differences in the weight and morphological composition of eggs depending on the genotype of the hens. Compared to eggs obtained from Hy-Line Brown hens, eggs from Messa 43 hens had significantly lower shell thickness, greater weight between 35 and 45 weeks of age,       a larger proportion of shell, and a smaller proportion of albumen. Yolks and whites of eggs from Hy-Line Brown hens contained significantly more dry matter and total protein than those of Messa43 chickens, while the cholesterol content in the yolks of both groups was similar. The fatty acid profile of the egg yolk was similar irrespective of the origin of the hens.

Conclusions: Significant differences in egg weight and the parameters of morphological components of eggs were found between the experimental groups. Genotype did not influence cholesterol content or the fatty acid profile in the yolk.