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).

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Abstract. The aim of study was to assess the growth performance, meat quality, and fatty acid composition of meat-type guinea fowl fed balanced commercial diets under two different feeding programs, similar to those for slaughter turkeys and broiler chickens, respectively. A total of 80 4-week-old meat-type guinea fowl divided into two groups (four replicates per group; 10 birds in each replicate) were raised for 14 weeks. One group received commercially available diets in a three-phased program (TM group), whereas the other group was fed commercial diets in a two-phased program (CM group). Growth-performance-related traits were recorded. At the end of rearing (14 weeks of age), eight birds from each group were slaughtered. Carcass yield and technological traits of meat (pH, color, water-holding capacity, natural and thermal loss, tenderness, fatty acid profile) were analyzed. Groups did not differ in terms of body weight as well as carcass yield and characteristics. There was no difference in meat quality and the fatty acid profile of breast and thigh meat of guinea fowl from TM and CM groups. The findings of this study suggest that both commercial diets (for broiler chickens and turkeys) can be used in meat-type guinea fowl rearing. Due to the lower price of diets fed to the CM group and the lack of significant variation in meat quality traits, its use seems to be more justified from an economic point of view.

Purpose The purpose of this paper is to evaluate changes in selected quality traits of chicken table eggs during their storage under standard storage conditions and in refrigeration. Design/methodology/approach The sample consisted of 570 eggs from Hy-Line hens. The eggs were placed on trays of 30 pieces each, and then group C (control) eggs were stored at 14°C temperature and 70 per cent humidity and group F (experimental) eggs were refrigerated at 5°C and 30 per cent humidity. Changes in egg mass and air cell depth were measured on the laying day and, then, after every 7 days for 5 weeks for group C and for up to 24 weeks for group F. Initially for every week and then after every four weeks, the quality of 30 eggs from each group was evaluated. The following traits were analysed: whole egg (mass, specific gravity), shell (conductivity, strength, mass, thickness, and density) and content (proportions, pH, albumen quality and yolk colour). Findings It was shown that due to a significant limitation of qualitative changes (lower water loss, higher specific mass, lower shell conductivity, better albumen quality, lower pH content, more favourable proportions of morphological elements) in eggs stored in refrigeration despite prolonged time, reduced temperature should be considered as a factor allowing for a significant prolongation of egg shelf life during storage. Originality/value The unusually elongated time of the experiment allows for a practical implementation of the results, especially in the case of eggs intended for processing.

Abstract. The aim of study was to evaluate the quality of hen eggs influenced by supplementation of copper with lysine chelate (CHL). The material consisted of eggs from two groups of Hy-Line Brown laying hens aged 300 days. Group I, negative control (NC), did not receive any additives. The hens from group II were treated with CHL at a dose of 30 mg Cu L −1 with drinking water. After 4 weeks of supplementation, 60 eggs from each group were randomly collected for quality analysis. The characteristics of the whole egg and its individual elements (shell, yolk, and albumen) were evaluated. The supplementation of CHL increased the egg weight, as well as the weight and height of albumen. There were no changes in the shell strength parameters, and its darker color may increase potential consumer acceptance, but requires confirmation by sensory analysis of the eggs. The copper addition was relatively small, but even this dose caused some changes in egg quality. Little changes in the mineral composition of individual elements of the eggs have been reported. It is therefore very important to continue research to find the smallest effective dose of this micronutrient, to study the duration of time it should be given in order to obtain the best quality of eggs, and to minimize the mineral disorders in organisms.