Sperm cryopreservation of freshwater fish bocachico (Prochilodus magdalenae) in DMSO and glucose and its effects on fertilization and hatching efficiency
Anim Reprod, vol.9, n1, p.19-26, 2012
Internal cryoprotectants (dimethylsulfoxide - DMSO), as well as external ones (glucose) have been of great importance for sperm cryopreservation in freshwater fish. The aim of this study was to evaluate both the fertilization and hatching rates of eggs fertilized with bocachico (Prochilodus magdalenae) spermatozoa cryopreserved in different combinations of DMSO and glucose. Nine treatments were evaluated by a combination of three concentrations of DMSO: 5% (701 mM), 10% (1402 mM), 15% (v/v; 2103 mM) and three concentrations of glucose: 5.5% (305 mM), 6% (333 mM), 6.5% (w/v; 361 mM). Semen from males obtained by abdominal stripping 6 h after hormonal induction with carp pituitary extract was submitted to each treatment. The semen was frozen in 0.5 ml straws in a nitrogen vapor dry shipper for 30 min and then in liquid nitrogen (-196°C). Five days later they were placed in water with a temperature of 60°C for 8 sec and analyzed. A high total motility (71.0 ± 7.0%) was observed when DMSO concentration was 10% and glucose was 6%, and a high linearity displacement (62.8 ± 6.3%) was observed when DMSO concentration was 5% and glucose was 5.5%. In conclusion, we found that for the purposes of cryopreservation of bocachico spermatozoa, the combinations of 10% DMSO + 5.5 or 6% glucose and 5% DMSO + 5.5 or 6% glucose produced the best results in terms of fertilization and hatching rates. This becomes the first report to successfully demonstrate the fertilizing capacity and larvae obtaining capabilities of cryopreserved bocachico semen.
computer assisted semen analysis, fertility, freshwater fish, hatchability, sperm cryopreservation