Authors
Abstract
Cryopreservation of fish embryos requires an optimal concentration of cryoprotectants inside all embryo compartments.In order to study the effects of cryoprotectants toxicity, two Persian sturgeon (Acipenser persicus) embryons (24 and 48 h after fertilization) were investigated using Methanol (MeOH), Ethylen glycol (EG) and 1,2- propandiol (PROH) (1 to 6 M), sucrose and honey (10,15 and 20%) and polyvinyl pyrolidon (PVP) (5, 10 and 15 %). Embryos were exposed using these cryoprotectants for 5 and 10 min. Embryos were then washed and incubated until hatching. EG was found to be the most toxic cryoprotectant. Persian sturgeon embryos tolerated MeOH better than EG compared to MeOH and EG, 1,2- propandiol gave the highest hatching rate and Persian sturgeon showed lower sensitivity in two embryonic development stage (24 and 48 h after fertilization). The hatching rate decreased with increasing concentration and exposure time in all treatments except sucrose and honey. Reduced hatching rate may be a result of osmotic shock, ionic imbalance or consequence of cryoprotectants toxicity. Finally with the progress of embryonic development among various cryoprotectants, sensitivity decreased in 1,2- propandiol and polyvinyl pyrolidon compared to MeOH, EG, sucrose and honey.
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