Short‐term preservation of porcine zygotes at ambient temperature using a chemically defined medium

Abstract We aimed to develop a simple method for the short‐term preservation of in vitro‐produced porcine zygotes at 25°C for up to 2 days. Firstly, we evaluated the efficiency of three storage solutions to preserve porcine zygotes at 25°C for 24 h. Two of these were commercially available defined media for cell storage (Cell‐W and Cell‐S), and the third was fetal bovine serum (FBS). Thereafter, we examined the effects of storing the zygotes in the Cell‐W solution for 24–72 h at 25°C. The Cell‐W solution was the most efficient for 24 h storage of porcine zygotes at 25°C, with no apparent effects on blastocyst quality. However, short‐term storage of porcine zygotes for 24 h reduced the blastocyst formation rate compared with the fresh control group. As storage duration increased from 24 to 48 or 72 h, blastocyst formation rates were significantly decreased from 11.3% to 4.4% and 0%, respectively. In conclusion, during zygote storage, the developmental competence to the blastocyst stage decreased with time. Storage of zygotes in chemically defined media did not affect blastocyst quality, but the storage in 100% serum had an adverse effect on developing embryos causing apoptosis.