Seasonal changes in the fatty acid composition of chicken egg yolks

<ns0:p>The demand for chicken eggs is constantly growing. Nowadays, eggs are a recognized component of a healthy human diet, so improving and ensuring their quality and nutritional value is a priority task. The aim of the work was to determine whether there were changes in the fatty acid composition of eggs depending on the season and in accordance with the established diet. During 4 seasons, eggs were selected from 12 laying hens of the Hercules breed of 240 days of age in one of the private farms of the Dubno district of the Rivne region, which practice free-range keeping. By gas chromatography (using a flame ionization detector), 20 fatty acids were detected and quantitatively identified in chicken egg yolks: myristic, myristooleic, pentadecanoic, palmitic, palmitoleic, margarine, heptadecene, stearic, oleic, linoleic, alpha-linolenic, gondoic, arachidonic, gamma-linolenic, eicosadienoic, eicosatrienoic, arachidonic, eicosapentaenoic, docosapentaenoic, docosahexaenoic. It was found that the mass fraction of saturated fatty acids in egg yolks significantly increased in the winter and autumn periods, namely by 25% higher relative to the level of saturated fatty acids in the summer period. Unsaturated fatty acids are mainly represented by oleic and linoleic acids. The mass fraction of oleic acid changed slightly and was within 38.12–40.64%, with a tendency to increase in the winter period. As for linoleic acid, its highest content was observed in the summer period (27.77±0.69), and the lowest was in the winter (20.43±0.80). Monounsaturated fatty acids tended to decrease in the summer period compared to the winter period. As for polyunsaturated, their highest content was observed in the summer, the lowest in the winter. Omega-3 fatty acids had a significant tendency to increase in the summer season compared to other seasons. Thus, it was established that the free-range system of laying hens and the appropriate diet can improve the nutritional profile of the yolk, thereby increasing its positive impact on human health.</ns0:p>