Effect of glucose concentration on sperm motility activation in bocachico Prochilodus magdalenae (Pisces, Characiformes)

Objective. To determine the concentration of non-activating glucose on sperm motility as a component of future extender for cryopreservation of Prochilodus magdalenae semen. Materials and methods. Inactive semen obtained by hormonal induction from 3 males was analyzed. From each male, 0.25 ?L of semen was deposited on Makler's chamber, and then a fixed amount of 75 ?l of glucose solution was added to each drop given a final concentration of, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10%. Each male was checked 3 times (n=3). Osmolarity was determined in each seminal sample (~250-300 mOsm/Kg) and into each solution, (0, 62, 124, 186, 250, 310, 360, 410, 472, 536 y 620 mOsm/kg, respectively. The software Sperm Class Analyzer (SCA) was used to determine the curvilinear (VCL ?m/sec) and straight (VSL, ?m/sec) velocity (VSL, ?m/sec), likewise, the rate of sperm motility (rapid, medium, and slow) was determined. Rate of immotile sperm was also determined. The activation time of motility (seconds) was obtained under light-field microscope. Results. Glucose Concentrations of 0 and 5% caused activation of sperm motility. Sperm activation was not visually detected in samples with glucose concentrations of 6% or higher. However, the SCA detected a total sperm motility of 7.2%, a VCL of 5.1 ?m/sec and a VSL of 1.7 ?m/sec. The SCA detected 100% non motile sperm in samples with 7% glucose solution and the motility was not subsequently acquired when distilled water was added. Conclusions. Glucose concentration has a determining effect on viability and activation of fresh sperm. Concentration of 6% glucose solution can be use as a non-activating solution for sperm motility in extenders for sperm cryopreservation in this specie.