DNA fragmentation and membrane damage of bocachico Prochilodus magdalenae (Ostariophysi: Prochilodontidae) sperm following cryopreservation with dimethylsulfoxide and glucose

The endangered bocachico Prochilodus magdalenae is a native freshwater fish of Colombia, the most captured species locally and one of the most important species for ex-situ conservation (germplasm banks). The aim of this study was to examine the effect of three concentrations of Dimethylsulfoxide (DMSO) (5%, 10%, 15%) and three of glucose (305, 333, 361 mM) in the extender on spermatic DNA fragmentation (F-DNA) (by Halomax®, Chromatin dispersion) and membrane damage (D-Me) (by eosin-nigrosin staining). After assessment of sperm quality by computer analysis of motility, one part of semen from males was diluted separately with three parts of extender and filled into 0.5 ml straws. Freezing was carried out in liquid nitrogen vapor dry shipper for 30 minutes and thawed at 60ºC for 8 seconds in a water bath and evaluated for the percentage of cells found with F-DNA and D-Me. The results demonstrated that cryopreservation causes greater F-DNA (13.62 ± 1.6% to 28.91 ± 3.25) and D-Me (24.27 ± 1.1% to 58.33 ± 2.81%) when compared with pre-freezing semen (PFS) (6.71 ± 1.54% and 2.34 ± 0.5%, respectively for F-DNA and D-Me). A significant interaction was found between DMSO and glucose concentration in this experiment. Use of extender: 10% DMSO + 305 mM glucose + 12% chicken egg yolk and, 10% DMSO + 333 mM glucose + 12% chicken egg yolk, allow for lower F-DNA and D-Me during cryopreservation of bocachico semen. A high correlation between F-DNA and D-Me was found (r = 0.771)