Electroejaculation,Semen Cryopreservation And In Vitro Capacitation Of Black Bears (Ursus Thibetanus G.)

An Electroejaculation technique was applied to Black bears (Ursus thibetanus G.) for semen collection and characterization of their seminal traits. Sperm electroejaculations were recovered from 23 of 18 bears. The mean values of ejaculation of black bears were: volume, 0.259 ?0.185 ml; PH, 7.0?.0; sperm concentration, 13.09 ?8.19xl08/ml; motility, 75.83 ?4.29%; status, 3.75 ?0.27; abnormal sperm percentage, 23.09 ?9.54%; intact acrosome percentage, 80.17?3.26%.In this study, black bears were immobilized with Ketamine hydrochloride (KH) or a combination of Ketamine hydrochloride and xylazine hydrochloride (KH-XH) or a mixture of Ketamine hydrochloride and Lumianning (KH-LM). The result indicated that the combination of Ketamine hydrochloride and xylazine hydrochloride (KH-XH) appeared to be more suitable for the electroejaculation of Black Bears. The drugs were used at a dose of approximately 8.44mg/kg weight of KH and 1.37 mg /kg weight of XH, and the induction time was 13.2min.Three different cryodiluents were used in this study: TEST, SFS and GFS. After freezing-thawing the percentage of sperm motility was 16.67%, 25.00% and 34.60% respectively, and the percentage of intact acrosome was 24.67%, 36.40%, 35.12% correspondingly. There was no difference among them(p>0.05). Freezing method A was better than method B and method C, however there was no difference in motility (25%, 15.9%, 20%) and in percentage of intact acrosome (36.4%, 31.79%, 35.33%) among methonds (p> 0.05). The motility was 25% of the black bear sperm after thawing in Ham'sFlO and the longevity was 6.5h which longer than that in TCM-199.The ability of black bear spermatozoa to penetrate zona pellucida of salt-stored mouse oocytes was examined as an assay for sperm capacitation. The oocytes were stored in a HEPES-buffered hypertomic salt solution. The freezing-thawing sperm, washed, swimmingup for Ih and then co-incubated in IVF-TALP medium containing 20ug/ml heparin and 5mmol/L caffeine (H+C) or in the same medium containing 20ug/ml heparin and 5% PCS (H+F) or the same one containing 45umol/L adrenalin and 70umol/L taurine.Treatments were compared for percentage ZP penetration (defined as sperm heads reaching more than halfway through the ZP and sperms reaching into the PVS) as an index of sperm capacitation. There was no difference (p>0.05)in sperm penetration of the two treatments that medium containing H+C (70.59%) and the one containing H+F (52.63%). Sperms incubated in the medium containing taurine were less capable of ZP penetration (30.0%) than the other treatments (p<0.05).