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Simple Summary: A ready supply of eggs has been provided for consumers throughout the years at a relatively low price sufficient to meet consumer demand. In response to the cage-free trend, adequate studies regarding the difference between the cage system and alternative systems are necessary due to the growing concerns about food safety and animal welfare, especially animal living conditions. Along with welfare concerns, there is rising consumer consciousness about the environmental sustainability of animal production. From this perspective, increasing persistency in lay and stability in egg quality would generate environmental and economic benefits. The present study investigated the effects of the enriched cage and free-range systems on the egg yolk nutrient composition at the late phase of the laying cycle (from the 68th week to the 74th week of age). The results of the present study indicated that the egg yolk lipid profile in terms of the total lipid, cholesterol, and fatty acid composition was not modified by the increasing age of laying hens. On the other hand, the results confirmed that the free-range system may improve the nutritional yolk fatty acid profile and its positive impact on human health, which can be a convincing support for the trend of "cage-free" eggs. In recent years, the free-range system for laying hens has increased, driven by societal sensitivity to animal welfare. This study aimed to comparatively analyze the total lipid, cholesterol, and fatty acid composition of egg yolks of late-age laying hens reared in enriched cages (C) and the free-range system (FR). Eggs were collected from Lohmann Brown Classic hens at the 68th, 70th, 72nd, and 74th week of age. The concentrations of total lipids and cholesterol were not affected (p > 0.05) by either factor. Egg yolk from the FR group showed lower (p < 0.01) monounsaturated fatty acids and higher (p < 0.01) polyunsaturated fatty acid (PUFA) compared with that of the C group. From a nutritional point of view, the PUFA n-6/n-3 and the PUFA/SFA ratios of egg yolk from the FR group were favorably lower and higher (p < 0.01) compared with the C one. Conversely, hen age did not affect (p > 0.05) the fatty acid composition of yolks. Interactions between factors were found for total n-3 and n-6 PUFA and the n-6/n-3 ratio (p < 0.01), as well as the thrombogenic index (p < 0.05). In conclusion, the results confirmed that the free-range system may improve the nutritional yolk fatty acid profile and its positive impact on human health. [ABSTRACT FROM AUTHOR]

In recent years, the free-range system for laying hens has increased, driven by societal sensitivity to animal welfare. This study aimed to comparatively analyze the total lipid, cholesterol, and fatty acid composition of egg yolks of late-age laying hens reared in enriched cages (C) and the free-range system (FR). Eggs were collected from Lohmann Brown Classic hens at the 68th, 70th, 72nd, and 74th week of age. The concentrations of total lipids and cholesterol were not affected ( p > 0.05) by either factor. Egg yolk from the FR group showed lower ( p < 0.01) monounsaturated fatty acids and higher ( p < 0.01) polyunsaturated fatty acid (PUFA) compared with that of the C group. From a nutritional point of view, the PUFA n-6/n-3 and the PUFA/SFA ratios of egg yolk from the FR group were favorably lower and higher ( p < 0.01) compared with the C one. Conversely, hen age did not affect ( p > 0.05) the fatty acid composition of yolks. Interactions between factors were found for total n-3 and n-6 PUFA and the n-6/n-3 ratio ( p < 0.01), as well as the thrombogenic index ( p < 0.05). In conclusion, the results confirmed that the free-range system may improve the nutritional yolk fatty acid profile and its positive impact on human health.