Graphene oxide enhances post-thaw sperm quality in tropically-adapted rams

This study investigates the effects of graphene oxide (GO) on the quality of frozen-thawed ram semen. Each of 30 ejaculates from five rams were cryopreserved with a control extender (Optidux®, Reprodux Inc., Brazil) or extender containing GO concentrations at 5, 50, or 100 µg/mL. Post-thaw data were analyzed using Tukey’s or Dunn’s t test (p < 0.05). Graphene oxide at 5 and 50 µg/mL increased frozen-thawed total (50.4 ± 3.15; 52 . 0 ± 2.76%), and progressive sperm motility (44.2 ± 3.06; 45 . 7 ± 2.68%) vs control (42.0 ± 2.75; 36.7 ± 2.58%), and sperm viability (56.3 ± 2.17; 57.8 ± 2.82%) vs control (48.8 ± 2.60%); and decreased immotile spermatozoa (49.6 ± 3.15; 48.0 ± 2.76%) vs control (58.0 ± 2.75%). Both 5 and 100 µg/mL treatments improved DNA integrity (90 ± 0.34; 90.5 ± 0.44%) vs control (89.1 ± 0.37%). There were no GO effects on sperm morphology, VCL, VAP. Local motility, an undesirable parameter, increased significantly from 5.42 ± 0.52% (control) to 6.77 ± 0.43% (100 µg/mL GO). Supplementation with GO improved post-thaw sperm progressive motility (by up to 24.5%) and viability (up to 18.4%), reducing immotile sperm (up to 17.2%), compared to extender alone. This potentially supports the practical use of GO as an additive to semen extenders. • Extender supplemented with graphene oxide (GO) improved post-thaw sperm quality. • Extender + GO at 5 and 50 µg/mL improved post-thaw sperm motility by up to 24.6%. • Extender + GO at 5 and 50 µg/mL increased post-thaw sperm viability by up to 18.4%. • Extender + GO reduced immotile sperm number and protected sperm DNA after freezing. • GO has potential use as an additive to extenders for ram semen cryopreservation.