Effects of chilled storage and pH of activating solution on different motility parameters in burbot (Lota lota) sperm

The effects of a simple saline solution prepared using two different pH (4.4 and 8.5) on sperm motility in burbot were investigated. Results were recorded during a 96-hour chilled storage (4°C) in 24-hour intervals. Measurements were focused on the detailed characteristics of motility using 12 parameters obtained from the Computer-assisted Sperm Analysis (CASA). Significantly higher progressive motility (pMOT), distance average path (DAP), distance curved line, distance straight line (DSL), average path velocity (VAP), curvilinear velocity, straight line velocity, and beat cross frequency (BCF) were observed with the activating solution buffered at pH 8.5 in comparison with pH 4.4. Already after 24 h a significant reduction was measured in pMOT (0 h: 49 ± 24%, 24 h: 12 ± 7%). Similar decreasing tendency was recorded only after 72 h in DAP (0 h: 26 ± 4 µm/s, 72 h: 19 ± 9 µm/s), DSL (0 h: 21 ± 5 µm/s, 72 h: 17 ± 8 µm/s), VAP (0 h: 59 ± 9 µm/s, 72 h: 43 ± 21 µm/s), and BCF (0 h: 28 ± 2 Hz, 72 h: 18 ± 10 Hz). The response of different investigated CASA parameters to different treatments varied in our experiments. According to our studies, numerous burbot sperm motility parameters are sensitive to chilled storage and to low pH of the activating solution. Our results could support the effective sperm quality assessment and successful artificial propagation process in burbot.