An efficient methodology for cryopreservation of spermatozoa of red seabream, Pagrus major, with 2-mL cryovials.

摘要

The aim of this study was to optimize the cryopreservation protocols for the sperm of red sea bream, P. major. The 2-ml cryovials and programmable freezer were employed for cryopreservation. Six extenders, six cryoprotectants in various concentrations ranging from 6-20% (v/v), four cooling rates and three thawing temperatures were evaluated by postthaw sperm motility and fertility. The ratio of sperm to egg for postthaw sperm fertilization trials was experimentally standardized and was optimal at 500:1. The best motility of postthaw sperm (79.4+or-4.7% to 88.6+or-8.0%), fertilization rates (89.6+or-2.9 to 95.6+or-1.9%) and hatching rates (85.3+or-5.1% to 91.4+or-4.3%) were achieved when Cortland extender, dimethyl sulfoxide (15, 18 and 20%) or ethylene glycol (9 and 12%) as cryoprotectants, 20 degrees C/min as the cooling rate and 40 degrees C as the thawing temperature were employed. Moreover, the results on embryonic development were not significantly different between cryopreserved sperm and fresh sperm during incubation process. In conclusion, these methods of cryopreservation of red sea bream sperm are suitable for routine aquaculture application and preservation of genetic resources..