The effect of changes in glucose and fructose levels in Tris-based extender on ram sperm kinematic parameters stored at body temperature

Storage of semen in the liquid form rather than cryopreservation is becoming popular as preparing and transportation is less expensive in this method. While maintaining the optimal osmolarity in all Tris-Egg yolk based extenders (TEY), the purpose of the present study was to investigate the effect of sugar type (glucose and fructose) and sugar concentration modifications on ram semen kinetics during incubation at body temperature. The semen diluents with different Sugar: Tris ratios (30 mM: 300 mM and 210 mM: 100 mM) were made with two different monosaccharide (glucose and fructose) and were compared with a standard extender used for freezing ram semen. The results showed that regardless of the diluent medium, the mobility parameters of sperm significantly decreased after incubation for two hours at 37°C. There was no significant interaction between storage time and type of extender. Also, the percentage of total motility and progressive motility were not significantly influenced by treatments. However, some of the motility parameters of incubated semen samples, including linearity, curvilinear velocity (VCL) and straight-line velocity (VSL) were improved by enhancing concentration of sugars in diluents. It is concluded that an increase in sugar: Tris ratio in TEY extenders, may improve the kinematic parameters of ram semen at body temperature. Thermoresistance of spermatozoids at body temperature can be considered as an indicator of male gametes fertility inside the female reproductive tract.