Effect of different concentrations of trehalose and glycerol on the freezability of ram semen using soybean lecithin-based diluents

Abstract

This study was conducted to determine the effect of different levels of trehalose and glycerol on ram sperm cryosurvival using lecithin-based diluents. Ejaculates were collected from four rams, pooled after initial evaluation, diluted with Tris-soybean lecithin extender and split into nine equal parts. A total of 0 (T0), 50 (T50) or 100 (T100) mM of trehalose and 3% (G3), 5% (G5) or 7% (G7) of glycerol were added to each part. Sperm motility, viability, plasma membrane integrity and acrosome integrity were evaluated immediately after thawing (0 h), and subsequently after 3 h and 6 h post-thawing incubation at 37°C. Results indicated that there was interaction between trehalose and glycerol on sperm motility. In addition, interaction of trehalose and glycerol with incubation time on sperm motility, viability, plasma membrane integrity and acrosome integrity was not significant (P > 0.05). Sperm motility was greatest in the sperm treated with 100 mM trehalose and 7% glycerol (27%; P < 0.05). The effect of trehalose was significant on viability and plasma membrane integrity of ram spermatozoa (P < 0.05). The main effect of trehalose showed that sperm viability was higher in T100 (47.06%) than T50 (53.96%; P < 0.05). The highest membrane integrity was observed in T100 (47.04%; P < 0.05). Membrane integrity was higher (P < 0.05) in G5 (49.97%) than G3 (41.56%) and there was no difference between G7 (46.86%) and G3 (41.56%; P > 0.05). The best sperm viability and plasma membrane integrity was observed at 0 h (65.75% and 51.58%, respectively). It was concluded that simultaneous use of 7% glycerol and 100 mM trehalose had a desirable effect on motility of ram frozen–thawed sperm.