Exploring the transcriptomic and metabolomic associations with fetal overgrowth in Holstein cattle derived from in vitro embryo production

Calves derived from in vitro embryo production (IVP) often have higher birth weights than those produced by artificial insemination or in vitro embryo transfer. The overgrowth in uterus may increase the incidence of calving assistance and thus, causes the potential health issue for dams. Research on the mechanisms underlying the IVP calve with large weights remains scarce. Therefore, this study aims to characterize molecular features associated with increased birth weight in IVP calves and identify candidate genes and metabolic pathways for further investigation. In this study, whole‑transcriptome, metabolomic, physiological, biochemical, and hormonal analyses were used to compare nine IVP calves with increased birth weight and nine IVP calves with normal birth weight. The results indicated that increased birth weight in IVP calves was accompanied by prolonged gestation length in recipient dams, and multiple physiological, biochemical, and hormonal parameters were significantly altered. Untargeted metabolomics identified 3,259 metabolites, among which 132 differential metabolites were screened, including 82 significantly up‑regulated and 50 significantly down‑regulated metabolites. Two candidate axes were identified in the ceRNA network: circ36279‑bta‑miR‑431 (with predicted targets SPON2 , TNN , INSIG1 , and AEN ) and circ35151‑bta‑miR‑154b (with predicted targets SHD , TBX2 , and IL20RA ). Comparison of independently enriched KEGG pathways identified five overlapping pathways. Pearson correlation analysis of selected differentially expressed genes and differential metabolites within these pathways revealed cross-omics associations. Arginine and proline metabolism was selected as a recommendation for further examination of gene expression and metabolite abundance differences. This study characterized physiological and biochemical differences associated with increased birth weight in IVP calves and identified two candidate ceRNA axes and cross-omics associations involving arginine and proline metabolism.