Comparative study of chemical components in hen eggs: free-range Canary hens vs. commercial breeds

Abstract

The growing interest of consumers in sustainable and differentiated quality products, along with the efforts of the ‘Asociación La Campera para la Recuperación de La Gallina Campera Canaria’, to gain recognition for this native breed and promote its production, justifies this study. The research evaluates the nutritional value of these eggs produced in the Canary Islands compared to those from commercial hens. To this aim, the ash, moisture, crude protein contents and lipid profile of 100 + 30 eggs obtained from four variants of the Canary Island free-range hen (Negra, Jabada Negra, Jabada Dorada and Rubilana) and from two commercial hens (Isa Brown and Leghorn) were determined. During the study, all hens (33 in total), were reared on the floor with the same diet and the same housing and natural lighting conditions without stressors. Analyses followed standard official and chromatographic methods. Statistical comparisons were made using parametric or non-parametric tests, depending on data normality. The results showed that eggs from Canarian variants exhibited higher levels of dry matter, ash, protein, and unsaturated fatty acids compared to commercial breeds; they also showed greater total weight and lower cholesterol content. If we highlight the individual results of the commercial breeds, Isa Brown eggs contained the lowest cholesterol level, while Leghorn eggs displayed significantly the highest total and liquid weights and protein content. Furthermore, the Canarian Jabada Dorada egg showed the highest nutritional value. Its superior weight and composition, particularly its higher protein content and lower cholesterol versus other studied breeds and varieties, make it ideal for healthy diets.