Compatibility of dry incubator on in vitro production of bovine embryos

Embryo culture is crucial to achieve successful outcomes in in vitro production-embryo transfer for cattle. This study explored the innovative use of dry incubators for bovine embryo culture, building on their advantages in human medicine, such as reduced contamination risk, stable temperature control, and lower gas consumption. In this study, we examined changes in osmotic pressure, the in vitro developmental potential of IVP embryos including the cleavage rate, blastocyst development rate, blastocyst diameter, and blastocyst cell number, morphokinetics, and the transcriptional profile of the blastocysts between humidified and dry incubators. Our research demonstrates the feasibility of this approach, showing that although the osmotic pressure gradually increases over the culture period (on day 8: 271.7 vs. 299.0, respectively; P = 0.09), it did not negatively affect the blastocyst formation rate (62.4 % vs. 69.8 %) and the morphological quality of blastocysts (diameter: 237.4 vs. 242.8, total cell number: 189.2 vs. 242.8). Embryos cultured in dry incubators exhibited morphokinetics comparable to those cultured in conventional humidified incubators. Furthermore, RNA-seq revealed that while a few genes showed changes, the transcriptomic profiles of blastocysts cultured in dry incubators were largely similar to those of blastocysts cultured in humidified incubators. These findings highlight the considerable potential of dry incubators for the in vitro production of bovine embryos.