Modulating fatty acid profile of egg yolk: Mechanistic insights into the development of functional eggs

Modification of egg yolk fatty acid composition has emerged as a major strategy for developing functional eggs with enhanced nutritional value and potential health benefits for consumers. Although extensive research has demonstrated that dietary interventions can substantially alter yolk lipid composition, current knowledge remains fragmented because nutritional, physiological, molecular, and technological factors are frequently investigated in isolation. This review proposes an integrated mechanistic framework describing egg yolk fatty acid remodeling as a coordinated biological process extending from dietary lipid ingestion to ovarian deposition through dynamic regulation of the gut-liver-ovary axis. The review synthesizes current understanding of intestinal lipid digestion and absorption, hepatic fatty acid metabolism, lipoprotein assembly, endocrine regulation, mitochondrial function, oxidative homeostasis, and ovarian lipid transport, while critically evaluating the regulatory roles of nutrition, genetics, epigenetics, gut microbiota, physiological status, and environmental factors. Emerging insights from nutrigenomics, multi-omics, systems biology, precision nutrition, artificial intelligence, and digital poultry technologies are integrated to demonstrate how these approaches can transform empirical dietary manipulation into predictive biological engineering. Evidence across diverse studies is critically synthesized to establish areas of strong consensus, resolve major scientific controversies, identify hidden biological patterns and sources of heterogeneity, and define the strength and limitations of current knowledge. The review further proposes major unresolved questions, paradigm shifts, translational implications, and transformative research priorities that collectively provide a roadmap for future investigation. By redefining egg yolk fatty acid remodeling as an integrated systems-level process rather than a direct consequence of dietary lipid supplementation, this review establishes a conceptual foundation for developing next-generation functional eggs that simultaneously optimize nutritional quality, laying performance, production efficiency, and sustainability.