Boar sperm velocity and motility patterns under capacitating and non-capacitating incubation conditions

Abstract

This study compares the velocity and motility of boar sperm under capacitating and non-capacitating incubation conditions. Aliquots of pooled, washed boar sperm were incubated in either Tyrode’s complete medium (TCM; a capacitating medium), Ca 2+-free TCM (TCM-Ca 2+), or Ca 2+ and NaHCO 3-free TCM (Tyrode’s basal medium [TBM]; a non-capacitating medium). Motility patterns were determined every hour over a 3 h period of incubation at 38 °C. Capacitation status was assessed by the chlortetracycline assay after 1 and 3 h of incubation. Experiments were repeated five times. Compared to the TBM control, a significant increase was seen in the percentage of capacitated sperm after 1 h of incubation in TCM: the kinematics of these sperm cells were favorably modified. However, the motility patterns of sperm cells incubated in TCM and TCM-Ca 2+ were very similar. Under capacitating conditions (TCM), the coefficients of linearity (LIN) and straightness (STR) significantly increased over time (LIN values were significantly different after 3 h of incubation, while STR values were significantly different after only 2 h). Significant correlations were seen between LIN and the percentage of cells showing the B pattern ( r = 0.334, P < 0.05) and the number of acrosome reacted spermatozoa ( r = 0.301, P < 0.05). This suggests that capacitated boar spermatozoa may have a species-specific motility pattern.