Effect of genotype and age of laying hens on the quality of eggs and egg shells

Abstract

The paper presents the results of testing of the egg and egg shell quality of two light line hen hybrids (Tetra SL and Bowans Brown). There were total of 4 tests. At the end of 35, 45, 55 and 65 weeks of age, the external and internal egg quality properties were tested as well as the quality of egg shell. Testing was conducted on a sample of 30 eggs for each hybrid. The weight and egg shape index were determined for each egg, as properties of the external quality, also internal quality properties such as albumen height and value of Haugh units (HU), and of the egg shell qualities - measured the egg shell deformation, the shell breaking force, the weight of raw shell and egg shell thickness were determined. The weight of the eggs did not differ significantly under the influence of said factors. Significantly higher mean values of the egg shape index at the age of 35 weeks were determined in comparison to 65 weeks of age. Under the influence of genotype, significantly higher (p<0.05) values of the albumen height in genotype Tetra SL were recorded. Albumen height in the 35th week of age was significantly higher (p<0.01) compared to other ages. Tetra SL layers showed significantly higher (p<0.05) HU values. With the increase of the age of hens the value of this parameter decreased, so, in the 35th week of age, statistically significantly higher HU value (p<0.01) was determined, compared to other ages. Deformation of the egg shell, breaking force and egg shell weight did not differ significantly influenced by genotype and age of laying hens. Significantly higher egg shell thickness values (p<0.05) were recorded for genotype Bowans Brown. With the increase of age of laying hens, there were no significant changes in egg shell thickness. Overall, it is concluded that both examined hybrids in terms of egg and egg shell quality traits have given satisfactory results. For most of the egg quality traits, better results were observed for Tetra SL hen genotype, while the most egg shell quality traits were in favour of hens of Bowans Brown genotype.