Housing environments link egg taste through metabolic alterations in laying hens

Abstract

Farm animal welfare is increasingly recognized as a core component in sustainable protein production. The transition to welfare-friendly housing systems—such as from cage to cage-free systems for laying hens—promotes the expression of motivated behaviors by providing greater space and resources, although it is associated with higher production costs and product prices. However, it remains unclear whether such systems generate value-added animal products, for example, through improvements in taste or nutritional quality, which may limit the wider adoption of animal welfare practices. Here, we show that housing environments shape differences in egg taste through metabolic changes in laying hens. Using an integrative approach combining human sensory evaluation, metabolomics, and transcriptomics of eggs and liver, we found that cage eggs were characterized by enhanced creaminess, likely reflecting lipid-related metabolic profiles, whereas cage-free eggs showed stronger umami and sweetness-related attributes associated with amino acid metabolism. These findings suggest that the physical environment, independent of feed composition, alters egg composition via changes in the internal metabolism of laying hens, leading to distinct taste characteristics. These differences are modulated by cooking processes, suggesting that eggs from different housing systems are better suited to different types of dishes.