Cryopreservation of common carp sperm

Experiments were carried out to investigate the effect of five extenders (sucrose, glucose, fructose, KCl and a saline carp sperm extender) and two cryoprotectants (dimethyl-sulfoxide (DMSO) and methanol) on the cryopreservation of common carp sperm. Freezing of sperm using glucose extender and methanol as cryoprotectant resulted in the highest post-thaw motility, fertilization as well as hatching rates (63 ± 9%, 74 ± 15% and 67 ± 17% vs. 87 ± 5%, 84 ± 14% and 69 ± 14% using fresh sperm, respectively). In general, sugar-based extenders combined with methanol as cryoprotectant yielded higher motility, fertilization and hatching rates than ionic extenders in combination with DMSO. The jelly-like agglutination observed after thawing in samples frozen with sugar-based extenders did not reduce fertilization and hatching rates. Frozen–thawed sperm samples were able to successfully fertilize 10 g (8000) eggs