Effect of lactose extender with different levels of osmolality and pH on the viability of Bactrian camel (Camelus bactrianus) spermatozoa

The effect of different levels of osmolality and pH of lactose extender on the viability of Bactrian camel spermatozoa was investigated. Semen was collected from 10 Bactrian camel bulls using modified bovine artificial vagina. In experiment I, the extenders consisted of 9, 10, 11, 12 and 13% lactose with respective osmolalities of 290, 333, 350, 376 and 419 mOsm/kg and the pH of 6.9. In experiment II, 10% lactose extender with different levels of pH = 5.9, 6.9, 7.5, 7.9 and 8.9 were compared. All extenders contained 20% egg yolk and antibiotics. There were three replicates (ejaculates) for each trial. After dilution, semen was evaluated for progressive forward motility (PFM), plasma membrane integrity (PMI) and live percentage of sperm, at time 0, 4, 12 and 24 hrs after incubation at 4°C. Viability of sperm was similar among 9-11% lactose concentrations at time 0 and 4. PFM was compromised (<8%) at 10 and 11% lactose extenders at time 12. Although, PFM was greatest at time 0 (P<0.05) for the pH of 6.9, it reduced to 15% at time 4 (P<0.05). At the pH of 5.9-7.9, PMI and live percentage of sperm reduced at time 12 and 24, respectively (P<0.05). In conclusion, 9-11% lactose with the pH of 6.9 may consider as a suitable extender for the short-term preservation (up to 4 hrs) of Bactrian camel semen maintained at chilled condition (4°C).