Uterine histotroph and conceptus development. VI. Progressive metabolomic remodeling accompanies porcine conceptus elongation and post-elongation development

Porcine conceptus elongation during the peri-implantation period is essential for establishment of pregnancy and involves rapid morphological and biochemical remodeling. However, metabolomic alterations within developing porcine conceptuses during this developmental interval are poorly understood. Therefore, the objective of this study was to characterize metabolomic remodeling in porcine conceptuses between gestational Days (GD) 10 and 16 using liquid chromatography-mass spectrometry (LC-MS)-based metabolomics and targeted amino acid analyses. A total of 230 metabolites were identified in conceptuses collected on GD10, 12, 13, 14, 15, and 16. Principal component analyses revealed progressive temporal separation of metabolomic profiles during conceptus elongation and implantation. Conceptus elongation was associated with progressive remodeling of metabolites related to nucleotide biosynthesis, phospholipid metabolism, amino acid metabolism, redox regulation, and energy metabolism. Random forest analyses identified cytidine diphosphate-ethanolamine (CDP-ethanolamine) and nucleotide-associated metabolites as key discriminators of progression in conceptus development. Targeted amino acid analyses of conceptuses demonstrated progressive increases in glutamine, glutamate, histidine, valine, arginine, and cystine, whereas tryptophan, glycine, and serine decreased during later stages of development. These coordinated changes support increased requirements for nucleotide synthesis, membrane biogenesis, redox homeostasis, and nutrient metabolism during rapid elongation and subsequent extraembryonic growth and differentiation. Collectively, these findings define metabolic transitions associated with porcine conceptus elongation and post-elongation development and provide candidate metabolic processes for future mechanistic investigation.