Effects of various cryoprotective agents on post-thaw drone semen quality

Abstract

The aim of the present study was to evaluate the effect of different cryoprotectants on post-thaw semen motility and plasma membrane integrity of drone spermatozoa. Semen was obtained from mature drones (16 days or older) harvested from four colonies. Collected semen was diluted to a final concentration of 1/5 (semen/extender) in 0% cryoprotectant (control), 6% glycerol, 6% Ethylene Glycol, 6% 1,2 propanediol or 6% DMSO using a two-step dilution method. The equilibrated semen was frozen in 0.25-ml straws. The percentage of sperm motility and swollen tails (HOST) spermatozoa were evaluated following dilution with extender A (non-cryoprotectant), equilibration and post-thaw stages. In terms of post-thaw motility and plasma membrane integrity recovery we can rank the used cryoprotectant as DMSO, Ethylene Glycol, Glycerol and 1,2 Propanediol; respectively. In conclusion, post-thaw sperm motility and plasma membrane integrity of the present study was significantly better when sperm was frozen in DMSO with respect to control, glycerol, ethylene glycol, 1,2 propanediol (P<0.05).