Effect of adding L-glutamine to Tris diluent on cryopreservation of coated sperm of Taleshi ram

Experiment was conducted to evaluate the effect of L-glutamine on coated sperm freezing by using four rams. Semen was collected by artificial vagina contact with a tube containing Tris-fructose-egg yolk 15%. Samples were pooled and centrifuged. After removing supernatant and diluting pellet، samples were split into 5 equal part and added 0، 40، 80، 120 and 160 mM L-glutamine. Samples were frozen by using liquid nitrogen After two weeks، samples were thawed and incubated at 37 °C for nine h. Sperm motility، plasma membrane integrity، viability (Hoechst 33258) and acrosome reaction (PNA-Alexa -flur-488) were investigated at 0، 3، 6 and 9 h. The main effect of L-Glutamine showed that sperm viability was higher in 0 (35. 95%)، 40 (40. 65%) and 80 (45. 95%) mM L-Glutamine than 160 mM L-Glutamine (30. 40%; P<0. 05). There was an interaction between incubation time and L-Glutamine on sperm motility and plasma membrane integrity (P<0. 05). After thawing and 3 h later، the highest of plasma membrane integrity was observed in 80 mM L-Glutamine (49. 25% and 47. 34% respectively; P<0. 05). Nine hours after thawing، the highest of sperm motility (26. 4%) was observed in 80 mM L-Glutamine (P<0. 05). Therefore، the addition of 80 mM L-glutamine to Tris-glycerol diluent (5%) improves coated sperm survival.