BS in Animal Science
Animal Science Department
Experiments were conducted to determine which of two direct in-straw rehydration methods was optimal for obtaining high survival of mouse embryos after repeated vitrification. The first vitrification method compared was a one-step design, designated “House method,” where embryos were equilibrated in 3.5 M ethylene glycol for 3 min before rapid plunge vitrification in 7 M ethylene glycol/0.5 M glucose/18% w/v Ficoll 70. The second method was the commercially available BoviPRO Embryo Vitrification Kit TM(MiniTube of America, Verona, WI), which first exposed embryos to 1.4 M glycerol for 5 min, then 1.4 M glycerol/3.6 M ethylene glycol for 5 min, followed by vapor vitrification in 3.4 M glycerol/4.6 M ethylene glycol. Survival rates for morulae and early blastocysts once-vitrified by the BoviPRO were superior to that of the House method. However the re-expansion rate decreased significantly when re-expanded blastocysts were vitrified a second time with the BoviPRO method. The House method proved to be the superior method for the re-vitrification of expanded blastocysts when compared to the BoviPRO method but was only moderately successful for the vitrification of in-vivo produced mouse morulae and early blastocysts.