Various protocols of feline spermatozoa cryopreservation have been reported and used in clinical practice. To compare the quality of post-thawed epididymal spermatozoa subjected to two different sperm freezing protocols, sperm samples were collected from domestic cats (n=7) after castration and divided into 2 aliquots as for Protocol 1 (P1) or Protocol 2 (P2). In P1, after centrifugation, sperm pellets were extended with Tris-based egg yolk extender (TEY) containing 3% glycerol and held for 60 min (5°C) prior to the second dilution (1:1) with 7% glycerol and 1% Equex STM Paste. The straws were frozen by lowering the goblets in three steps into a LN2 tank. In P2, sperm pellets were re-suspended in TEY free of glycerol, left for 15 min at room temperature before the addition (1:1) of TEY containing 8% glycerol and 1% Equex. After loading into 0.25-ml straws at room temperature, the sperm were cooled to 5°C for 25 min and subsequently frozen in a Styrofoam box at 4 cm above LN2 for 10 min. Thawing was done at 37°C for 1 min. No significant differences (P>0.05) between the two protocols (P1 vs P2) in all parameters were observed; total motility (30±8.1 vs 30±3.4; mean±SEM), progressive motility score (3±0.2 vs 3±0.2), percentage of spermatozoa with intact plasma membrane (38.5±4.5 vs 44.5±6.9) and intact acrosome (34±3.2 vs 38±4.7), respectively. In conclusion, both protocols used in the present study yielded similar post-thawed sperm characteristics.
Thammapradit, Kanokwan and Ponglowhapan, Suppawiwat
"Evaluation of two cryopreservation protocols on cauda epididymal spermatozoa characteristics in domestic cats,"
The Thai Journal of Veterinary Medicine: Vol. 48:
1, Article 1.
Available at: https://digital.car.chula.ac.th/tjvm/vol48/iss1/1