Virginia Institute of Marine Science
Journal Of Shellfish Research
Factors such as osmotic pressure, extender solution, addition of caffeine, and pH have been shown to affect sperm motility in aquatic species. We evaluated the effects of 18 osmotic pressures, two extender solutions, seven caffeine concentrations, and a pH range of 3 to 14 on motility of sperm from tetraploid Pacific oysters, Crassostrea gigas. Motility was highest at 1000 mOsmol/kg (mean +/- SD: 83 +/- 14%). Calcium-free Hanks' balanced salt solution yielded significantly higher sperm motility than did artificial seawater. Sperm motility increased with caffeine concentrations to 20 mM (81 +/- 12%) and decreased when concentrations were higher than 50 mM (55 +/- 20%). Highest motility was obtained at a pH range of from 4 to 12; values outside this range yielded no motility. Addition of 10 mM caffeine to the different pH treatments also enhanced motility significantly. Overall, calcium-free Hanks' balanced salt solution at 1,000 mOsmol/kg, the addition of 10 mM caffeine, and a pH of around 10 could be used to enhance sperm motility of tetraploid Pacific oysters. Our findings would assist the use of motility assays to evaluate the effectiveness of various refrigeration or cryopreservation procedures, especially outside of the peak spawning season, when sperm motility can be low and variable.
Crassostrea Gigas; Sperm Motility; Ph; Caffeine; Osmotic Pressure; Tetraploid; Cryopreservation
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Dong, QX; Eudeline, B; Allen, Standish K. Jr.; and Tiersch, TR, Factors Affecting Sperm Motility Of Tetraploid Pacific Oysters (2002). Journal Of Shellfish Research, 21(2), 719-723.