A maternal ketogenic diet alters oviduct fluid nutrients and embryo histone acetylation in mice

A ketogenic diet elevates blood β-hydroxybutyrate to concentrations that perturb the development, metabolism, histone acetylation (H3K27ac) and viability of preimplantation mouse embryos in vitro. However, whether a ketogenic diet alters β-hydroxybutyrate concentrations within female reproductive fluid is unknown. This study aimed to quantify glucose and β-hydroxybutyrate within mouse blood and oviduct fluid following standard diet and ketogenic diet consumption and to assess whether a maternal periconceptional ketogenic diet impacts in vivo embryo development and blastocyst H3K27ac. Female C57BL/6 x CBA mice were fed a standard or ketogenic diet (n=24 each) for 24-27 days. Glucose and β-hydroxybutyrate were quantified in blood via an electronic monitoring system, and in oviduct fluid via ultramicrofluorescence. The developmental grade of flushed blastocysts was recorded, and blastocyst cell number and H3K27ac was assessed via immunofluorescence. A maternal ketogenic diet elevated β-hydroxybutyrate in day 24 blood (P<0.001) and oviduct fluid (P<0.05) compared with a standard diet, whereas glucose was unchanged. A periconceptional ketogenic diet did not impact blastocyst cell number, however, significantly delayed blastocyst development (P<0.05) and reduced trophectoderm-specific H3K27ac (P<0.05) compared with standard diet-derived embryos. Maternal ketogenic diet consumption is therefore associated with reproductive tract nutrient changes and altered embryonic development and epigenetics in vivo. Future studies to assess whether periconceptional/gestational ketogenic diet consumption impacts human preimplantation, fetal, and long-term offspring development and health are warranted.