The Variability of Quality Traits of Table Eggs and Eggshell Mineral Composition Depending on Hens' Breed and Eggshell Color.

Abstract

Simple SummaryThe quality of the bird’s eggshell is extremely important because it constitutes a barrier that protects the developing embryo from external conditions. The shell color is a characteristic for a specific breed and its intensity is one of the basic selection criteria, especially among ornamental breeds of hens. The presence or absence of a specific dye is genetically determined, and environmental conditions or nutrition affect it only to a negligible degree. The shell is an inorganic part of the egg. Differences in the mineral composition are determined mainly by the feeding system and the age of birds, although differences are also observed between the lines or breeds, so probably also due to the color. The content of given elements affects the shell quality, determining its strength, thickness, or preventing the appearance of defects that affect the hatching results. In case of table eggs the variability of colors is attractive for consumers, particularly if the differences are extreme (white, green, brown). Based on the study, it was clearly visible that genetically determined eggshell color affects not only the quality of shell itself but also the whole egg parameters.The aim of the study was to evaluate the relationship between the eggshell color parameters and its mineral composition as well as the internal quality of eggs derived from various breeds of hens, varied by eggshell color: seledine from Araucana, brown from Marans, and white from Leghorn. The sample consisted of 180 eggs (60/group) The eggshell color was measured using CIE L*a*b* system. The quality evaluation included traits of whole egg (weight, specific gravity, proportions of elements, shape index), yolk (weight, color, index, pH), albumen (weight, height, pH), and shell (color, strength, weight, thickness, density). The mineral composition of eggshells was analyzed. The eggs origin affected the quality characteristics of particular egg elements (p < 0.001). However, the impact of analyzed colors on the egg quality traits varied, and in the case of whole egg and albumen traits the most favorable was the white color (p ≤ 0.05), while in the case of the strength of shell or its thickness it was the dark brown color (p ≤ 0.05). The eggshell color influenced variations in its mineral composition (p < 0.001) except potassium and sodium content, while the proportion of particular mineral elements in shell was correlated with the L*a*b* color space coordinates (p ≤ 0.05).