Study On Gamete Cryopreservation Techniques In The Blue Mussel Mytilus Galloprovincialis

Gamete cryopreservation is a valuable technique that can enhance the efficiency of genetic improvement programs and endangered species conservation.Therefore,this technique is important for the marine germplasm conservation,breeding program and aquaculture industry.The blue mussel Mytilus galloprovincialis is an important marine bivalves species and protecting its superior germplasm is vital for the industry long-term and sustainable development.This study optimized the gamete cryopreservation steps in order to improve the survival rate which could provide the critical technique for the conservation.The results showed as follows:(1)The highest post-thaw fertilization(42.47%)and D-larval(18.13%)rates were achieved when the oocytes were cryopreserved with 10% EG+7.5%FIC and 0.2%PVP and thawed in 9% sucrose.For the subsequent development,no significant difference was found between the fresh and cryopreserved oocyte treatments.(2)For the sperm cryopreservation,the highest post-thaw fertilization(91.91%)and D-larval(67.36%)rates were achieved when the sperm were mixed with8% DMSO+0.8%glycine,frozen at-5 oC/min to-40 oC,thawed at 50-60 oC.The addition of glycine in DMSO can significantly improve the fertilization rate of sperm after cryopreservation.(3)When the cryopreserved sperm and oocytes were fertilized,the fertilized oocytes could develop to D-larvae.When the sperm to egg ratio at 200:1,the highest fertilization(35.34%)and D-larvae(9.33%)rates were produced.When cultured for 25 days,D-larvae could develop to eye larvae.When cultured for 32 days,they could develop to spat.The research results provide a scientific basis and technical support for the long-term preservation of the purple mussel germplasm.