Physicochemical parameters and morphological qualities of edible eggs depending on the period of the reproductive period of chickens

Abstract

Abstract Changes in egg quality observed under intensive poultry farming conditions indicate the possibility of regulating these parameters without violating their inherent high nutritional benefits. Morphological characteristics, such as the weight and shape of the egg, the weight of the yolk, protein, shell, its strength and others are determined mainly by genetic factors and conditions of keeping and feeding. Egg mass is the most important physical indicator of nutritional and market value, which determines the productivity of poultry. At 26 weeks of age (beginning of laying) the egg weight averaged 57.7 ± 0.81 g, and at 80 weeks of age (end of laying) - 62.2 ± 1.86 g. The weight of eggs obtained from hens of the cross “Lohmann-white”, increased due to changes in the absolute mass of its constituent components. The mass of egg white during the reproductive period increased by 4.50–4.99%; yolk - by 6.8-14.9%; shells - by 4.4-18.8%, although this practically did not affect their ratio in percentage terms. The shell thickness increased from 365.0 ± 6.99 microns to 378.0 ± 7.09 microns. With an increase in the shell thickness, the density of eggs also increased from 1.070 ± 0.002 g / cm3 to 1.078 ± 0.002 g / cm3. The shape index of eggs ranged from 71.5 - 74.9%, while the increase in egg mass was accompanied by a decrease in the shape index. During the reproductive period, the Howe index was at the level of 82.5-84.4 conventional units. The protein index and Howe units decreased with age. All morphological and physicochemical parameters corresponded to the optimal values: protein index from 7.6 to 8.4%, yolk index from 39.0 to 42.0%, shape index from 74.9 to 75.3, Hau units from 82, 5 to 84.4 conventional units.