Synergistic Effect of Permeable and Impermeable Cryoprotectants on the Survival and Hatching Rate of Sutchi Catfish (Pangasius hypophthalmus) Embryos Treated at Subzero Temperatures

ABSTRACT- The sutchi catfish (Pangasius hypophthalmus) has been widely introduced for aquaculture industry in Asiatic countries. The cryopreservation of catfish embryos is important to facilitate stock enhancement programs.The present study was designed to determine the effect of combination of permeable and impermeablecryoprotectants on survival and hatching of catfish embryos aiming to understand the basic conditions for their conservation by vitrification. Sutchi catfish embryos at somites and optic cups were treated at room temperature, 4 o C, 0 o C and -20 o C, with impermeable sucrose as a factor of dehydration and membrane stability, separately or in different combination with glycerol, methanol (MeOH), ethylene glycol (EG), and propanediol ( P G). The obtained results show that the catfish embryos are sensitive to low temperature and the hatching rate was significantly decreased for embryos treated at temperature below 0 o C. Catfish embryos are able to perform a partial dehydration in 0.5 M, 1.0 M and 2.0 M sucrose, respectively. Dehydration with 2.0 M sucrose has high protective effect for embryos treated at 0 o C. The combination of dehydration and MeOH, PG and EG at high concentration of more than 5.0 M can be used safely to keep embryos at 0 o C and -20 o C for short duration. In conclusion, present information related to cryobehavior and cryoprotectants was established for further study of vitrification in catfish embryos. Normal 0 21 false false false FR X-NONE X-NONE