The current status of sperm cryopreservation of the endangered Probarbus jullieni (Sauvage) in Malaysia.

摘要

The objective of this study was to develop a cryopreservation method in Probarbus jullieni sperm, an endangered riverine fish species in Southeast Asia, including the optimization of an extender solution (14 extender formulations were tested) and selecting a cryoprotectant (five types of agents and methanol were used at concentrations (v/v) of 5, 7.5, 9, 10, 12, 15 and 20%). The semen to diluent ratios tested were as follow: 1:1, 1:2, 1:3, 1:4, 1:5, 1:7, 1:9, 1:14, 1:19, 1:24 and 1:49. Vapour exposure duration was set at 5, 10, 15 and 20 min while the distance between sample and liquid nitrogen (LN₂) during the vapour exposure was designed at 3, 3.5, 4, 5 and 6 cm. Further, the time frame for thawing was set at 6, 7, 8, 10, 20 and 30 s. The optimum protocol was by using CF-HBSS (pH 7.5, osmolality 285+or-10 mOsmol kg-1) in combination with methanol at 9% (v/v); sperm to diluents ratio between 1:3 to 1:5; vapour exposure for 5 min or 10 min, with samples placed at 3.5 cm or 4 cm above LN₂ and thawing at 40 degrees C for 7 s. The mean of pre-frozen and post-thaw sperm motility was 80.1+or-13.6% (n=43) and 49.6+or-16.4% (n=43) respectively. The reproductive characteristics of P. jullieni during its spawning season were addressed in present work. Cryopreserved sperm was found to have lower fertilization ability (4.2+or-2.5%, n=1050) and hatching rate (1.6+or-1.2%, n=1050) compared with fresh sperm (fertilization 77.7+or-6.2%, n=1050; hatching 64.7+or-7.7%, n=1050). The resulted problems and constraints encountered in the process of sperm cryopreservation of the species studied were also reported in this paper.Digital Object Identifier http://dx.doi.org/10.1111/j.1439-0426.2010.01539.x