Cryopreservation of white-tailed deer (Odocoileus virginianus) semen using soybean-, liposome-, and egg yolk-based extenders

•Non egg yolk semen extenders are effective to cryopreserve sperm in white-tailed deer.•Soybean extenders preserve sperm motility superior than some egg yolk extenders.•Liposome extenders produce similar sperm motility as soybean extenders.•Non egg yolk extenders effectively preserve sperm viability, acrosome integrity and chromatin stability.

The objectives of the present study were to compare the use of soybean-based (Andromed), liposome-based (Optixcell), and egg yolk-based (Ovine Red, Triladyl, and Biladyl) extenders for cryopreservation of white-tailed deer semen. In experiment 1, ejaculates obtained from six bucks were aliquoted into the following extenders: Andromed, Ovine Red, Triladyl, and Biladyl (containing 4%, 6%, or 8% of glycerol). In experiment 2, ejaculates obtained from eight bucks were divided amongst Andromed, Ovine Red, and Optixcell extenders. Total and progressive sperm motility were assessed for each sample before and after cryopreservation using a computer-automated semen analyzer. In experiment 2, flow cytometry was used for post-thaw assessment of sperm viability (SYBR-14/PI), acrosome integrity (FITC-PNA/PI), and chromatin stability (acridine orange). In experiment 1, both Andromed and Ovine Red extenders exhibited higher post-thaw total motility than Biladyl containing 4% or 6% of glycerol (p < 0.05). Andromed also produced higher progressive motility than all other extenders (p < 0.01) before and after cryopreservation with no differences amongst the other extenders (p ≥ 0.11). In experiment 2, there were no differences in total and progressive motility between Andromed, Ovine Red, or Optixcell extenders (p ≥ 0.39). Additionally, there were no differences in sperm viability (p = 0.18), acrosome integrity in viable sperm (p ≥ 0.10), or DNA fragmentation index (p = 0.15). These results demonstrated that soybean (Andromed) and liposome-based (Optixcell) extenders are equally as effective at cryopreserving white-tailed semen as egg yolk-based Ovine Red extender, but are superior to egg yolk-based Biladyl or Triladyl extenders.