Cryopreservation of Goldlined seabream Rhabdosargus sarba (Forsskål, 1775) sperm: CASA observation and enzyme activity evaluation

In this study, we developed an optimized cryopreservation protocol for goldlined seabream sperm through five small experimental groups: Diluting the sperm with a mixed cryoprotectant (containing 10 g/L glucose and 10% DMSO in an RS extender) at a ratio of 1:3, followed by equilibration at 4 °C for 30 min. Subsequently, the samples were subjected to liquid nitrogen steam fumigation at 5 cm above the surface for 5 min before drop in the liquid nitrogen. Using computer-assisted sperm analysis (CASA), we examined the motility parameters of the sperm before and after freezing for 2 days, as well as the changes in energy metabolism enzyme (T-ATP, LDH, SDH) activities and antioxidant enzyme (T-GSH, CAT, SOD, and GSH-px) activities at 0, 5, 10, and 20 days after freezing. After 250 days cryopreservation, fluorescence staining of sperm showed that most cell membranes were less damaged, and the fertilization rate of sperm after 250 days cryopreservation was 72.53 ± 7.32%. objective of this study was to select an effective cryopreservation protocol for goldlined seabream sperm and elucidate the physiological damage mechanisms before and after cryopreservation.