Abstract
The cysts of Artemia franciscana (A. franciscana) exhibit strong tolerance to desiccation and freezing. However, when cysts are hydrated, advantageous resistance to environmental factors is markedly reduced. Here we report the evaluation of freezing damages after cryopreservation of decapsulated hydrated cysts, and improved hatching ratio by the treatment of cryoprotectants such as dimethl sulfoxide (DMSO). The hatching rate of decapsulated hydrated cysts declined shortly at rapid frozen (submerged in liquid nitrogen), but high hatching rates maintained at slow freezing rates (-0.5℃/min). We also observed the surface of frozen hydrated cysts using a scanning electron microscope attached with cryo-transfer system (Cryo-SEM), and found fine structural discrepancy in the section of embryos between two freezing speeds.
