15 SEPTEMBER 1999
TOXICITY OF SELECTED CRYOPROTECTANTS ON TROCHOPHORE LARVAE OF MYTILUS EDULIS
B. Tompkins, C. Couturier-1998
Bulletin of the Aquaculture Association of Canada, 98-2 (contributing papers Aquaculture Canada '98): 68-70
Abstract:
The toxicity of three known cryoprotectants was examined as a preliminary step to establishing a protocol for the cryopreservation of Mytilus edulis trochophore larvae. Trochophore larvae were subjected to ethylene glycol, dimethyl sulfoxide, or sucrose, at three concentrations, and the effect of equilibration temperature (4 C and 15 C) on the survival of cryoprotectant-challenged trochophores was assessed. Larvae were considered to have survived if they underwent metamorphosis to the D-stage. There were no significant differences in toxicity among the three cryoprotectants. Survival varied inversely with cryoprotectant concentration in all treatments. Equilibration temperature had little effect on the toxicity of ethylene glycol and dimethyl sulfoxide. In contrast, the survival of larvae exposed to sucrose was higher at 4 C than at 15 C. The inverse relationship between cryoprotectant concentration and survival suggests the cryoprotectants cause both osmotic and biochemical stress to the trochophores. The cryoprotectants probably act indirectly as well by altering membrane permeability to selected ions. Lower equilibration temperatures are believed to reduce metabolic demands and hence biochemical toxicity, which would account for the reduced toxicity of sucrose at the lower temperature.
(Centre for Aquaculture and Seafood Development, Marine Institute of Memorial University, Box 4920, St. John's, NF, Canada A1C 5R3, e-mail of C. Couturier: cyr@gill.ifmt.nf.ca)