Evaluation of goat semen frozen with different additives

This study investigated the effects of adding a ROCK inhibitor and resveratrol, added to a Tris-based extender, on post-thaw spermatozoal parameters in cryopreserved Ankara buck semen. For this purpose, two separate experiments were designed by combining ejaculates obtained from four normospermic Ankara male goats aged 4-6 years using an electroejaculator. In Experiment 1, ROCK inhibitor (R) was added to Tris-based extenders containing 5% Glycerol (G5) and 3% Glycerol + 50 mM Trehalose (G3T) at doses of 5, 15, and 45 µM, forming extender groups G5, G5R5, G5R15, G5R45, G3T, G3TR5, G3TR15, and G3TR45. In Experiment 2, Resveratrol (R) was added to Tris-based extenders containing 5% Glycerol (G5) and 3% Glycerol + 50 mM Trehalose (G3T) at doses of 100, 300, and 900 µM, forming extender groups G5, G5R100, G5R300, G5R900, G3T, G3TR100, G3TR300, and G3TR900. The combined sperm samples were diluted separately with the diluent groups from Experiments 1 and 2, then drawn into straws and left to equilibrate, after which they were frozen in liquid nitrogen vapor and stored. After thawing, spermatozoa motility, plasma membrane and acrosome integrities, and mitochondrial activity were evaluated. In Experiment 1, the G5R15 significantly improved the post-thawed motility (66.25±0.82%) and mitochondrial activity (51.88±2.61%) compared to the other groups (p<0.05). There was no statistically significant difference between the groups in terms of plasma membrane integrity (p>0.05). Regarding acrosome integrity, the G5R5 (75.50±2.93%), G5R45 (73.25±2.53%), G3T (72.25±3.90%), G3TR5 (80.25±2.23%), G3TR15 (73.88±2.75%) and G3TR45 (71.50±4.33%) groups provided a higher level of protection than the G5R15 (61.63±2.61%) (p<0.05). In Experiment 2, the highest post-thawed motility (51.25±2.27%) was obtained in the G3T group. The G3T showed a higher rate of improvement in the post-thawed motility compared to the G5R100 (39.38±2.90%), G5R300 (43.13±2.82%), G5R900 (25.00±1.64%) and G3TR900 (30.63±1.99%) groups. The highest result in plasma membrane integrity was obtained in the G3TR100 (33.25±2.43%), providing higher protection than the G5 (19.75±4.58), G5R100 (17.13±3.13), G5R300 (14.50±1.74), G5R900 (9.25±0.77), G3TR300 (23.25±3.06) and G3TR900 (15.13±2.35) groups (p<0.05). There was no statistically significant difference between the groups in terms of acrosome integrity (p>0.05). The G3T (35.75±2.62%), G3TR100 (37.00±3.70%) and G3TR300 (33.14±4.34%) groups significantly improved mitochondrial activity compared to the G5R300 (19.75±1.87%) and G5R900 (15.63±3.69%) (p<0.05). In conclusion, it was determined that certain doses of ROCK inhibitor and resveratrol improved the post-thawed semen quality. Furthermore, it was concluded that the G3T extender containing trehalose could be used instead of the G5 extender to reduce the toxic effects of glycerol.