Cryopreservation of Bagrid Catfish Hemibagrus wyckioides Spermatozoa

Abstract

In order to establish a protocol for the cryopreservation of Bagrid catfish (Hemibagrus wyckioides) spermatozoa, semen was collected from male Bagrid catfish through surgical testis removal technique. The research objectives were 1) to determine the effect of three cryoprotectants on sperm motility, 2) to establish cryopreservation procedures by comparing various extenders and cooling rates, and 3) to estimate the spermatozoa fertilization potential by comparing artificial fertilization between cryosperm and fresh sperm. The cryosperm was stored for 30 and 365 days, and thawed for the second and third experiments, respectively. Methanol had the least toxic effect to the sperm whereas DMSO had the most toxic effect. The use of 6% fructose and 5% glucose as extenders, 10% (v/v) methanol as cryoprotectant, and cooling rates of 2 and 5°C/min showed higher thawed sperm motility, compared with using GFR as an extender, 10% methanol and 10°C/min cooling rate. The percentage of eyed stage egg between thawed and fresh sperms was not different. The results also suggested that Bagrid catfish semen could be diluted to 15 folds dilution before mixing with eggs during artificial fertilization.