Changes in Fatty Acids Profile, Health Indices, and Physical Characteristics of Organic Eggs from Laying Hens at the Beginning of the First and Second Laying Cycles

SIMPLE SUMMARY: Eggs are some of the most valuable components of the human diet. Nowadays, the “trend” is for humans to follow healthy lifestyle behaviours. Moreover, special emphasis is placed on animal welfare and in the handling of animals. Thus, hen-laying cycles are more often extended (or ended) by moulting, followed by another cycle, instead of depopulation. Egg quality during the life of a hen was monitored to optimise the hen’s age of the cycle ending (in terms of fatty acid composition and its impact on human health). The present study compared the egg qualities from hens, of two laying cycles, regarding the fatty acids profile, and hypocholesterolemic, atherogenic, and thrombogenic indices. Younger hens had higher albumen and yolk indices, Haugh units, and eggshell strength; monounsaturated fatty acids (MUFAs) were lower and saturated fatty acids (SFAs) were higher. The polyunsaturated fatty acid (PUFA) n-6/n-3 ratio, saturation, atherogenic, and thrombogenic indices were significantly lower in the egg yolks from older hens compared to younger layers. These findings prove that it is practical to utilize them in the organic farming system during a period of two years. ABSTRACT: The present study compared the fatty acid profile and some physical parameters of eggs from hens reared according to the organic system at the beginning of the first and second laying cycle. A total of 1080 eggs were analysed at the beginning of the first (from the 28th to 30th week of age) and the second (from the 78th to 80th week of age) laying cycle. It was found that the hen ages influenced the egg weight, egg surface area, yolk proportion, and eggshell colour. Albumen and eggshell proportion, albumen, yolk index, Haugh unit score, and eggshell strength were lower in eggs from older hens compared with those produced from younger layers. Monounsaturated fatty acids were found in higher amounts than saturated fatty acids and polyunsaturated fatty acids in egg yolks of eggs from layers only at the beginning of the second laying cycle. The PUFAn-6/n-3 ratio, saturation, atherogenic, and thrombogenic indices were significantly lower in the egg yolks from older hens compared to younger layers. These findings (regarding the eggs from the older ones) prove that it is practical to utilize them in the organic farming system during a period of two years.