Effects of Equex on the survival of bactrian camel (Camelus bactrianus) sperm in chilled and frozen conditions.

摘要

Damage to the plasma membrane of sperm could reduce the viability of sperm following freeze-thaw processes. This problem could be overcome by using membrane stabilizers. This study investigated the effect of anionic detergent on the viability of chilled and frozen-thawed bactrian camel sperm. In experiment 1, semen of good quality was extended in SHOTOR diluent with or without 1% Equex (v/v; NOVA Chemical, USA) and Green buffer. The viability parameters of sperm were evaluated at the time of collection and at the times 0, 12 and 24 h after reaching 4 degrees C. In experiment 2, good quality semen was diluted with SHOTOR diluent and chilled to 4 degrees C. Then an equal volume of chilled freezing media with or without 1% Equex (NOVA Chemical, USA) was added gradually to the chilled diluted semen to achieve final Equex concentration of 0.5% (v/v). Then, specimens were loaded into 0.5 ml straws, and placed on a rack standing at 4 cm above the surface of liquid nitrogen. Overall, it took 60 min from adding freezing medium until exposures of the straws to the liquid nitrogen vapour. It took 20 min prior to immersing the straws into liquid nitrogen. After one week, thawing was performed in a water bath, set at 40 degrees C, for 20 sec. The viability parameters of sperm were assessed immediately after thawing. Progressive forward motility (PFM) decreased in SHOTOR+Equex (19.0%) when compared with those for IMV (56.5%) and SHOTOR (59.5%) after 12 h of chilling. After 24 h, SHOTOR (51.5%) and IMV (48.0%) exhibited greater PMI when compared with SHOTOR+Equex (29.0%; P=0.06) extenders. At this time, the percentage of live sperm was higher (P<0.05) for SHOTOR (75.0%) and IMV (74.5%) than those of SHOTOR+Equex (41.0%) extenders. There was no significant difference in PFM (16.0 vs. 19.7%), plasma membrane integrity (28.0 vs. 31.3%) and percentages of live sperm (42.0 vs. 42.6%) between two media after thawing when comparing freezing media with and without Equex. It is concluded that Equex at 0.5% v/v concentration does not improve the post-thaw viability of bactrian camel sperm.