Fig. 6

Clustering analysis of epididymal sperm trajectory in capacitating conditions with different HCO₃⁻ concentrations. A) Boar epididymal spermatozoa were incubated in capacitating medium (TALP) containing different concentrations of HCO₃⁻ (0 mmol/L, 5 mmol/L, 15 mmol/L and 25 mmol/L) and CASA parameters were determined at 1, 15, 30 and 60 min of incubation in 3 replicates. Clustering of spermatozoa was carried out per field. Cluster 1: lowest values in all CASA parameters (poorest motility). Cluster 2: high values of VSL, LIN, STR and WOB (the most linear trajectory). Cluster 3: high values of VCL and ALH and low of VSL, LIN and STR (the most curvilinear trajectory). Data were analysed by one-way ANOVA and a Tukey test. Results expressed as mean ± SEM. Different letters (a, b) in the different experimental groups (0 mmol/L, 5 mmol/L, 15 mmol/L and 25 mmol/L) of the same cluster indicate statistically significant differences (P < 0.05). B) Illustrations are representative of the 3 clusters defined