Factors affecting survival of cryopreserved oyster (Crassostrea gigas) embryos

A conventional two-step freezing procedure was developed and optimized in o rder to cryopreserve oyster embryos. The effects of cooling rate, choice of cryoprotectant, and seeding temperature on the survival of late-stage oyst er embryos were examined. When these factors were optimized, improved survi val rates of 78 +/- 8 and 83 +/- 7% were achieved using 2 M Me2SO or glycer ol, respectively, as the cryoprotectant. The experimental results indicate that oyster embryos survive after freezing over a broad range of cooling ra tes ranging from -0.5 to -16 degrees C/min Me2SO, glycerol, propylene glyco l, and ethylene glycol may be used as cryoprotectants for the cryopreservat ion of oyster embryos. (C) 1999 Academic Press.