Vitrification of in vitro produced bovine embryos at different ages using one- and three-step addition of cryoprotective additives.
The effect of embryo age on development and ratio of live: dead cells after vitrification and warming was examined. One-step and three-step addition of cryoprotectants in vitrification solution (40% ethylene glycol, 0.3 M trehalose and 12% polyvinylpyrrolidone) were compared using in vitro produced (IVP) bovine blastocysts and expanded blastocysts. Rates of development and hatching were 74.2% and 41.9% for Day 7, 57.8% and 23.8% for Day 8, 33.7% and 6.1% for Day 9 embryos with one-step addition. In three-step addition, those rates were 86.2% and 77.3% for Day 7, 72.3% and 39.0% for Day 8, 47.3% and 10.5% for Day 9 embryos. Day 7 embryos showed highest (P < 0.01) development and hatching rates with one exception. Hatching rate of Day 7 embryos with three-step addition was higher (P < 0.01) than with one-step addition. The ratio of live:dead cells differed between one-step (94%) and three-step (97%) additions for Day 7 embryos (P < 0.05). The results indicate the higher resistance of younger IVP bovine embryos against vitrification and the potential for three-step addition of cryoprotectants to yield a higher survival rate after warming than with one-step addition.
Saha
S
S
Farm Animal Reproduction Biotechnology Laboratory, Faculty of Agriculture, Yamaguchi University, Japan. ssaha@niai.affrc.go.jp
Suzuki
T
T
D000818:Animals; D001755:Blastocyst / Q000502:physiology; D002417:Cattle / Q000196:embryology*; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D005314:Embryonic and Fetal Development; D019855:Ethylene Glycol; D005260:Female; D005307:Fertilization in Vitro; D011205:Povidone; D013997:Time Factors; D014199:Trehalose
D003451:Cryoprotective Agents; D014199:Trehalose; D019855:Ethylene Glycol; D011205:Povidone