Effects of sublethal mild hypothermia on kinetics, transcriptome, and cryotolerance of in vitro produced bovine embryos

In Experiment 1, embryos were exposed to hypothermia for either 6 or 12 h on day 5 or 6 of development, and the blastocyst rates and kinetics were evaluated. In Experiment 2, the transcriptome of embryos exposed to hypothermia on either day 5 or 6 for 12 h was assessed.

In Experiment 3, embryos were exposed to hypothermia for 12 h on day 6, vitrified‐ warmed, and their re‐expansion, apoptotic index, and total cell number were assessed. Results showed that hypothermia had no effect on blastocyst rate but reduced the percentage of hatched blastocysts when applied for 12 h. Moreover, hypothermia was associated with changes in the transcriptional profile, particularly in embryos exposed on day 6, including increased expression of the cold‐shock‐related transcripts RBM3 and CIRBP.