Modulation of lipid composition and gene expression by CNP supplementation in in vitro cultured bovine embryos

The objective of this study was to evaluate the effect of adding of C-Type Natriuretic (CNP) to the in vitro culture medium of bovine embryos on cryotolerability through modulation of lipid content and profile, as well as modulation of gene transcripts linked to embryonic metabolism. Initially, a concentration of 400 nM of CNP was used throughout the in vitro culture and blastocysts were collected for lipid content analysis by Sudan Black B. In addition, blastocysts were selected by morphological quality and developmental stage, and the samples collected were analyzed using MRM- profiling. After, blastocysts were vitrified using OPS. Subsequently the warming, hatched blastocysts were collected and evaluated for transcript abundance in a microfluidic platform. Differences of probabilities lower than P < 0.05, and/or fold change ˃1.5 were considered significant. The CNP group presented a reduction in the relative abundance of ions belonging to different lipid subclasses, such as acylcarnitine, sphingomyelin, cholesteryl esters, free fatty acids, and glycerophospholipid. Furthermore, the triacylglycerol lipids TG 52:3 NL 16:1, TG 56:3 NL 18:1, and the glycerophospholipid C22:6, were increased in the CNP group. A modulation of blastocyst transcripts was also observed by increased transcription of ATF4, and a trend statistical significance of BMP15 and GFPT2 transcripts. There was no difference in blastocyst development rates after warming of CNP-treated embryos.