Combined effects of physicochemical variables (pH and salinity) on sperm motility: characterization of sperm motility in European sea bass Dicentrarchus labrax

Gamete activation in fish is an important step in terms of artificial fertilization of oocytes, cryopreservation studies and other experimental manipulations. Salinity and pH differences in activation media affect to sperm motility and fertilizing ability. These experiments were therefore designed to investigate the combined effects of pH (range 5.0-9.0) and salinity (20, 30, 37, and 45 parts per thousand) of activation media on sperm motility of European sea bass Dicentrarchus labrax. The best results were obtained at salinity 37 parts per thousand and a pH of 9.0. Our results also demonstrated that non-progressive motility at salinity 45 parts per thousand was observed in the range of 5.0-9.0 pH. In conclusion, spermatozoa can be motile at a wide range of pH and salinity values although the percent of motile spermatozoa and motility duration are negatively affected by low pH values.