A. Niasari-Naslajia, S. Mosaferia, A. Moghiseha, D. Nikjoua, N. Bahmania, A. Geramib,AA. Moosavi-Movahedic, AA. Gharahdaghid, A. Abarghanie
aDepartment of Clinical Sciences, Faculty of Veterinary Medicine,
bSchool of Mathematics, Statistics and Computer Science,
cInstitute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
dAnimal Science Research Institute, Karaj, Iran
eResearch Centre For Agriculture and Natural Resources, Ministry of Jihad-e-Agriculture, Ardabil, Iran
ABSTRACT
Damage to the plasma membrane of sperm could reduce the viability of sperm following freeze-thaw processes. This problem could be overcome using membrane stabilisers. 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°C. In experiment 2, semen of good quality was diluted with SHOTOR diluent and chilled to 4°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°C, for 20s. The viability parameters of sperm were assessed immediately after thawing. Twelve hours after chilling specimen, progressive forward motility (PFM) reduced in SHOTOR+Equex (19.0%) compared to those for IMV (56.5%) and SHOTOR (59.5%). After 24 hr SHOTOR (51.5%) and IMV (48.0%) exhibited greater PMI compared to 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. Comparing freezing media with and without Equex, 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. In conclusion, Equex, at the concentration (0.5% v/v) and procedure used in the present study, did not improve the post-thaw viability of bactrian camel sperm.
Key words: Bactrian camel, Equex, freezing extender, sperm
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