Integrated Metabolomics Unravels Amino Acid Metabolic Signatures in Egg Albumen of Rongde Xiaoheiji and Taihangji

As the world's largest egg producer, China faces challenges in egg brand development by indistinct quality characteristics. This study employed untargeted and targeted metabolomics to systematically analyze 239 differentialy abundant metabolites (VIP >1, P <0.05) in breed Rongde Xiaoheiji albumen (RDA) and indigenous Taihangji albumen (THA). L-valine was identified as the most significant differential marker between breeds. Key differential metabolic pathways involved biosynthesis of amino acids and 2-oxocarboxylic acid metabolism. Targeted quantification revealed significantly lower levels of valine, leucine, and phenylalanine in RDA compared to THA, strongly correlated with isocitrate downregulation in amino acid biosynthesis. Metabolic profiling differences indicate that RDA exhibits potential superior advantages in antitumor functions, cognitive support, intestinal protection, and anti-inflammatory properties, while THA shows potential benefits in muscle protein synthesis, post-exercise recovery, neurotransmitter balance maintenance, and energy metabolism efficiency. This research provides novel perspectives for establishing metabolomic feature-based egg quality evaluation systems.