Enhanced cryosurvival of bovine blastocysts produced in vitro in serum-free medium.
OBJECTIVE
Culture systems affect the development of IVP embryos and consequently their cryosurvival potential. The viability of postthawed bovine IVP embryos developed from IVM/IVC medium in the presence or absence of serum was compared.


METHODS
Cumulus-oocyte complexes were matured in IVM medium supplemented with or without serum. Some oocytes were evaluated for nuclear maturation status and others were inseminated with semen. Presumptive zygotes were cultured in IVC medium supplemented with or without serum for 9 days. Blastocysts were cryopreserved with 1.5 M ethylene glycol in PBS.


RESULTS
No difference was observed in the nuclear maturation status and cleavage rates in both groups, but significantly (P < 0.05) higher in blastocyst rates in the serum-supplemented group. After freezing, survival of blastocysts was higher in the serum-free group. At 36 h culture after thawing, blastocysts developed without serum had significantly (P < 0.05) higher cell number than those cultured with serum.


CONCLUSIONS
We conclude that serum-free culture system enhances the viability of frozen-thawed bovine embryos.
Cho
Sang-Rae
SR
Department of Obstetrics and Theriogenology, College of Veterinary Medicine, Gyeongsang National University, Chinju, Republic of Korea.
Cho
Seong-Keun
SK
Lee
Sung-Lim
SL
Lee
Hyo-Jong
HJ
Choe
Sang-Yong
SY
Rho
Gyu-Jin
GJ
D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods; D002470:Cell Survival / Q000502:physiology; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D015925:Cryopreservation; D016895:Culture Media, Serum-Free; D004624:Embryo Transfer / Q000662:veterinary; D005307:Fertilization in Vitro / Q000662:veterinary*
D016895:Culture Media, Serum-Free