出版社：Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul
摘要：Aquaculture development is dependent on continuous seed production, regardless of the spawning
season. Cryopreservation can therefore, be a valuable tool for achieving seed availability. The benefits
of cryopreservation have been demonstrated for mammals, fish and some achievements have been
reported for invertebrates; however, cryopreservation has not yet contributed significantly to oyster
rearing. The literature on this topic demonstrates that an optimal cryopreservation method developed for
one species is not always applicable to another. One of the reasons is that there are differences among
species in the toxicological responses of gametes and embryos to cryoprotectants. The aim of this study
was to determine the toxic effects of cryoprotectants dimethylsulfoxide (Me2SO), glycerol (G), ethylene
glycerol (EG), propylene glycerol (PG) and methanol (MET) on Crassostrea rhizophorae gametes and
embryos). Gametes (oocytes and spermatozoa) and embryos (trochophores) were exposed to a range of
concentrations of each cryoprotectant for 10, 20 and 30 minutes. Based on the EC50-24h values there
were no significant differences (p > 0.05) among the exposure times in toxic effects to either gametes or
embryos. The trochophores were relatively resistant to cryoprotectant exposure, while oyster gametes
became increasingly susceptible to the cryoprotectants as concentration levels were increased. Critical
values (EC50-24h) of cryoprotectants were markedly different for gametes and embryos. For gametes,
both G and MET were more toxic (EC50-24h respectively of 3.46 and 4.52% for oocytes, and 2.07
and 11.21% for spermatozoa) than EG, PG and Me2SO. However, PG (EC50-24h = 23.56%) and
EG (EC50-24h = 45.18%) were more toxic for trochophores than Me2SO (EC50-24h = 54.25) or MET
(EC50-24h = 55.63%). These results show the importance of previous toxicological studies for
cryoprotectant selection as a preliminary step towards establishing cryopreservation protocols.
