Metabolomic Biomarkers in Bovine Embryo Culture Media and Their Relationship to the Developmental Potential of In Vitro Produced Embryos

We recently demonstrated that the metabolome of single embryo culture media is associated with successful pregnancy [13]. In this study, we expanded the analysis to compare the metabolomes of viable and nonviable early-stage embryos, as well as to examine metabolomic markers associated with hatching in viable embryos. We analyzed the metabolic profile of 43 spent bovine embryo culture media samples using liquid chromatography-mass spectrometry, covering 189 metabolites, including 40 acylcarnitines, 42 amino acids/biogenic amines, 91 phospholipids, 15 sphingolipids, and the sum of hexoses. The embryos were produced from abattoir-derived oocytes, and the culture media samples were derived from Grade 1 early blastocysts that progressed to hatching (n = 10), non-viable early blastocysts that developed to the blastocyst stage but failed to hatch (n = 12), Grade 1 hatched blastocysts (n = 16), and plain growth media for control (n = 5). We found that methionine sulfoxide (Met-SO) and Lysophosphatidylcholine C24:0 concentrations were significantly lower in the culture media from viable blastocysts compared to those from non-viable blastocysts (p < 0.001). Additionally, blastocysts that resulted in successful hatching had significantly lower levels of phospholipid, arginine and methionine-related metabolites that significantly differentiated the control and viable blastocyst culture media from the media containing non-viable embryos. Building on previous studies, there appears to be an overlap in metabolites released during hatching that are also associated with successful pregnancy. The identified biomarkers can aid in assessing an embryo's developmental potential and enhance embryo selection for transfer or cryopreservation.