Characteristics and fertility of Sumatran tiger spermatozoa cryopreserved with different type of cryoprotective sugars

抄録

The objectives of this study were to examine the characteristics and penetrability of Sumatran tiger spermatozoa cryopreserved with different type of cryoprotective sugars (lactose, glucose, and trehalose). Ejaculated semen were collected from two healthy male adult Sumatran tigers (SB#1099 and SB#1512) belonged to Taman Safari Indonesia, Bogor. The semen were cryopreserved in Niwa and Sasaki freezing (NSF) extender supplemented with 44 mg/ml of each sugar and 3% glycerol. Heterologous IVF with domestic cat oocytes was used to assess the penetrability of frozen-thawed Sumatran tiger spermatozoa. The value of sperm motility for semen cryopreserved with lactose was significantly higher than that for semen cryopreserved with trehalose (30.0 vs. 18.8, P < 0.05). There were no significant differences in the values of sperm viability and plasma membrane integrity among the groups. Frozen-thawed Sumatran tiger sperm were able to fertilize with in-vitro matured cat oocytes, irrespective of type of cryoprotective sugars. There were no differences in the rates of penetration and normal fertilization of sperm among the groups (28.8-45.5% and 65.3-72.4%, respectively). In conclusion, the type of cryoprotective sugar may affect the motility of frozen-thawed Sumatran tiger spermatozoa but not the in-vitro penetrability.