Semen cryopreservation in Bactrian camel (Camelus bactrianus) using SHOTOR diluent: Effects of cooling rates and glycerol concentrations

Experiments were conducted with a final goal of providing a suitable protocol for cryopreservation of Bactrian camel semen. In Experiment I, the effect of average cooling rate (slow cooling: 0.14 versus fast cooling: 0.55 °C/min) on the viability of chilled semen was evaluated. In Experiment II, the effect of different concentrations of glycerol (4, 6 and 8%) on the post-thaw viability of frozen sperm was investigated. In Experiment III, the efficiency of SHOTOR diluent was compared with IMV buffers for the cryopreservation of camel semen. Viability parameters including progressive forward motility (PFM), plasma membrane integrity and percentage of live spermatozoa were assessed. Progressive forward motility of sperm cooled at the faster rate was superior after incubating for 24 h at 4 °C compared to that cooled at the slower rate (P < 0.05). Post-thaw viability of Bactrian camel sperm was better using a final glycerol concentration of 6% compared to 4 and 8% (P < 0.05). Progressive forward motility of frozen-thawed sperm was greater using SHOTOR diluent (29.9%) compared to IMV buffers (4.2%, P < 0.05). In conclusion, semen cryopreservation in Bactrian camel is feasible when it is extended in SHOTOR diluent, cooled within 1 h (average cooling rate: 0.55 °C/min) to 4 °C, and then exposed to glycerol, at the final concentration of 6%.