A Review on Factors Influencing Success of Grouper Sperm Cryopreservation

Abstract

This review was conducted to support information gathering on development of sperm cryopreservation techniques and protocols including factors such as type of cryoprotectants, extenders, cooling rates and dilution ratio and the impacts of those factors towards sperm cryopreservation of 10 different grouper species. Groupers are high-value marine species that contribute significantly to the income of Southeast Asian countries which are important as aquaculture producers. Thus, sperm cryopreservation is essential to support the development of grouper seed production and culture. Giant grouper is the most studied grouper species due to the fast-growing ability which enables to produce high-value interspecies hybrids for commercialization purposes. The most used cryoprotectant for sperm cryopreservation among various grouper species is dimethyl sulphoxide (DMSO). Among the extenders, sodium chloride (NaCl) is reported to be the most commonly used due to easy preparation, relative effectiveness and availability of the solution which enables local farmers to easily extend storage of the grouper sperm. Most grouper species seem to have a wide range of optimal cooling rates. However, some species exhibit the narrow range of optimal cooling rates. Optimal cooling rates were also possibly affected by the type and concentration of cryoprotectant. Dilution ratios used to cryopreserve grouper sperm seemed to vary. Sperm of brown-marbled grouper and seven band grouper to report dilution ratios of 1:49 while other grouper species sperm worked better at dilution ratios of 1:1, 1:2, 1:4 and 1:9. Grouper sperm cryopreservation protocol in general is species-specific and the optimization has to be done species by species to increase overall productivity. Grouper sperm cryopreservation is applicable and can be used to enhance seed production.