Osmolality and composition of the activating solution affects motility of fresh and frozen Prochilodus lineatus sperm differently.

Osmolality and composition of the activating solution on motility of fresh and frozen Prochilodus lineatus sperm were evaluated. Sperm was triggered in 11 solutions prepared with reverse osmosis (RO) water (∼0mOsmkg(-1)), and glucose or NaCl adjusted to 50, 100, 150, 200 and 250mOsmkg(-1). Sperm motility rate and velocities (curvilinear=VCL, among others) were evaluated in fresh sperm at 10, 30 and 50s post-activation (spa), and in frozen sperm at 10 spa only. Sperm was frozen under a standardized methodology for this species. Fresh sperm motility was higher in samples triggered in RO (91%), in glucose at all osmolalities (90-92%) and in 50-150mOsmkg(-1) NaCl (88-91%) than that in 200-250mOsmkg(-1) NaCl (74-80%). Motility decreased (P<0.05) as a function of time after activation in samples activated in RO and in NaCl but not in glucose. Samples activated in 100-250mOsmkg(-1) glucose yielded motility above 80%, at 50 spa. Curvilinear velocity was higher (P<0.05) in glucose-activated samples (322-357μms(-1)) compared to that activated in NaCl (192-283μms(-1)) and in RO (298μms(-1)). Frozen sperm motility and velocities were similar when triggered in RO, glucose or NaCl and were higher at 0-150 mOsm kg(-1) (69-78% motility; 163-208μms(-1) VCL) than at 200-250mOsmkg(-1) (34-59% motility; 127-168μms(-1) VCL). High sperm motility with fast velocity for a long period is achieved at 100-150mOsmkg(-1), in glucose solution for fresh sperm and in glucose or NaCl for frozen sperm.