144 Dynamic of Sperm Subpopulations in Red Deer Capacitated Samples

Abstract

An ejaculate is a mixture of sperm subpopulations (SP) with varying motility characteristics. Moreover, males with high percentages of fast and linear-moving sperm have high rates of fertility (Ramón et al. 2003 Biol. Reprod. 89, 110). The objective was to assess dynamics, over time, of SP of capacitated red deer sperm. Thawed sperm were selected with 45/90% Percoll, diluted at 10 × 106 sperm mL−1 in SOF plus 10% oestrous sheep serum and incubated for 2 h at 38.5°C under 5% CO2. Sperm motility was assessed by computer-assisted semen analysis at 1, 5, 15, 30, 45, 60, and 120 min and 24 h. Sperm were classified as described previously (Martínez-Pastor et al. 2005 Biol. Reprod. 72, 316-327) and the evolution of SP during capacitation was characterised with piece-wise regression that identified change points. Five sperm SP were identified based on velocity according to an actual path (VCL), velocity according to a straight path (VSL), velocity according to the average, smoothed path (VAP), linearity (LIN), straightness (STR), wobble (WOB), amplitude of lateral displacement of sperm head (ALH), and frequency of the flagellar beat (BCF). Sperm in SP1 were fast, linear sperm with high ALH; they corresponded to capacitated sperm. In contrast, SP5 were slow, non-linear sperm, with low ALH (Table 1). The dynamics of each SP differed over time was different along the time. Percentages of SP1, SP4, and SP3 were significantly decreased at 60, 90, and 100 min, whereas percentages of SP2 and SP5 did not change over time. This study was consistent with previous reports that kinematic sperm characteristics change over time. Table 1.Sperm subpopulations (SP) based on kinematic end points.