Quantitative sperm characteristics of Tankwa goats with special reference to hyperactivated motility

Abstract

Computer-assisted semen analysis (CASA) is an automated and objective method of evaluating structural (e.g. morphology) and functional sperm parameters (e.g. motility and hyperactivation). Sperm hyperactivation is essential for successful fertilization and is thus an important aspect in determining the fertility potential of a male. In the current study, CASA was used for standard semen analysis and for comparison of the ability of phosphate buffered saline (PBS), BO sperm wash (10 mM caffeine), 4% lignocaine, and 5 mM procaine hydrochloride to induce hyperactivation in Tankwa goat spermatozoa. Twenty-nine ejaculates were collected from randomly selected male goats by electroejaculation. Although none of the four media affected percentage total sperm motility, lignocaine caused a significant decrease (P >0.05) in percentage progressive motility. Exposure to procaine resulted in an increase in swimming speed (P ≤0.05) and star-spin motility tracks, which are typical of sperm hyperactivation. Using PBS and procaine motility data from individually selected spermatozoa, receiver operator characteristic curves were constructed to distinguish the kinematic parameters employed as cut-off values for sperm hyperactivation. PBS and BO sperm wash did not induce hyperactivation (0.1  0.2% and 0.04  0.2% respectively), while lignocaine induced little hyperactivation (3.4  3.0%) and procaine hydrochloride had the highest percentage hyperactivation (25.3  13.6%). The large variation in hyperactivation (0–54.5%) may reflect inter-individual differences in sperm quality among these males. This study indicated procaine hydrochloride was the most promising hyperactivation-inducing medium for Tankwa goat spermatozoa and should be considered for similar assessments in other animal species.