Hypothermic storage of porcine zygotes in serum supplemented with chlorogenic acid.

The current study was conducted to investigate the effects of 100% foetal bovine serum (FBS) and 100% porcine follicular fluid (pFF) as a storage medium on the developmental competence of porcine zygotes stored at 25°C for 24 hr. Moreover, we evaluated the additive effects of chlorogenic acid (CGA) in the storage medium. When in vitro-produced zygotes were stored at 25°C for 24 hr in tubes containing either tissue culture medium (TCM) 199 supplemented with 1 mg/ml bovine serum albumin (BSA), 100% of FBS or 100% of pFF, the rate of blastocyst formation was significantly higher in 100% of FBS than in BSA-containing TCM 199. When the effects of CGA supplementation in 100% of FBS on the development of zygotes stored at 25°C for 24 hr was evaluated, more zygotes stored with 50 µM CGA developed to blastocysts compared with the other concentrations of CGA. When the formation date and quality of blastocysts derived from zygotes stored in 100% of FBS supplemented with 50 µM CGA were investigated, the highest ratio of blastocysts formation in the storage group appeared 1 day later than in the non-stored control group. However, a higher proportion of blastocysts with apoptotic nuclei was observed in the stored group as compared to the non-stored group. In conclusion, 100% of FBS is available for a short storage medium of porcine zygotes. The supplementation of 50 µM CGA into the storage medium improves the rates of blastocyst formation of zygotes after storage, but the quality of embryos from the stored zygotes remains to be improved.