Abstract
Objective: Primordial germ cells (PGCs) are essential for germline transmission and preservation of genetic resources in poultry. Despite identification of several genes and signaling pathways involved in PGC specification, the upstream regulatory mechanisms, including metabolic regulation and epigenetic modification, remain poorly understood. This study aimed to characterize the metabolic landscape underlying chicken PGC development and to identify key metabolic regulators involved in BMP4-induced specification of primordial germ cell‑like cells (PGCLCs) in vitro.Methods: Untargeted metabolomics and transcriptomics were performed to examine metabolic profiles and gene expression patterns between chicken embryonic stem cells (ESCs) and PGCs. Differential metabolites and metabolism-related genes were identified through integrated multi-omics analysis. Functional experiments, including glutamine deprivation and metabolite supplementation, were conducted to verify the role of glutamine metabolism in PGCLC specification.Results: A total of 194 differentially expressed metabolites were identified, mainly enriched in amino acid, nucleotide, energy metabolism, and antioxidant pathways. Compared with ESC, PGC contained elevated levels of amino acids, peptides, and benzoic acid derivatives, while carbohydrates were more abundant in ESC. Transcriptomic analysis of 14,405 annotated genes revealed similar metabolic gene expression patterns in male and female samples. Integrated analysis indicated that amino acid metabolism, particularly glutamine metabolism, is crucial in PGC formation. Glutamine deprivation significantly inhibited PGCLC specification, disrupted the balance between glycolysis and oxidative phosphorylation, and altered H3K4me2 epigenetic modification. Supplementation with the glutamine-derived tricarboxylic acid cycle metabolite α-ketoglutarate (α-KG) markedly restored the reduced efficiency of PGCLC specification caused by glutamine depletion.Conclusion: Glutamine promotes the specification of chicken PGCLC and correlates with alterations in cellular metabolism and increased H3K4me2 levels during differentiation. These findings suggest a potential association between glutamine metabolism, α-KG, and epigenetic regulation in germ cell development, providing new insights into the metabolic basis of PGC formation and a foundation for improving PGC culture and expansion in poultry.