Research Note: Changes in chicken egg yolk metabolome during its formation.

The process of egg yolk formation involves the transport and uptake of a large number of small molecule metabolites. A qualitative and relative quantitative analysis of metabolites in the 3 formation periods of egg yolk was performed by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical workflow. A total of 398 metabolites were identified, of which "amino acids and their metabolites", "lipid", and "organic acids and their derivatives" were the dominant egg yolk metabolite categories with the most metabolite species. The findings suggested that a number of amino acids, organic acids, nucleotides and their metabolites were deposited during follicular development to provide material support for later embryonic development. At the same time, some vitamins and carbohydrates were consumed during follicular development to support the normal development process. In addition, the small hierarchical follicle (SF) period may be a critical period for the regulation of the transport and deposition of some active ingredients. These results contribute to a comprehensive understanding of the nutrient deposition pattern and nutritional properties of egg yolk.