Freezing of Stallion Semen: In Vitro Evaluation of Motility and Acrosin Activity in Sperm Cells Cryopreserved Using Different Semen Extenders.

The research examines the effectiveness of different solutions in preserving horse semen during freezing and thawing, by looking at two measures of sperm quality – movement and enzyme activity. The study found that both solutions tested were equally good at maintaining the integrity of the sperm cells.

Research Methodology

• The experiment involved equine semen that was divided into two parts, each suspended in a 11% lactose solution for 20 minutes at room temperature.
• The semen was then centrifuged (spun at high speed) for 10 minutes, resulting in a solid pellet.
• Freezing extenders, Merck and Zorlesco, were added to each pellet and then put into 4 mL straws, which were subsequently frozen
• The freezing process involved initial exposure to liquid nitrogen vapor for 15 minutes followed by immersion in liquid nitrogen at -196°C for long-term storage.

Data Collection and Analysis

• After thawing, the semen samples were first analysed for sperm motility (total and progressive) and acrosin activity.
• Further assessment on these parameters was done at 60 and 120 minutes respectively, after incubation at 37°C.
• The preserved semen showed lower sperm motility and acrosin activity immediately after thawing, compared to fresh semen.
• Data showed a progressive decline in these measures during the thermoresistance test at 60 and 120 minutes.

Conclusions

• Both Merck and Zorlesco extenders were found to be similarly effective in preserving the integrity of frozen and thawed sperm cells.
• The decline in sperm motility and acrosin activity post-thawing and during the thermoresistance test were statistically significant, but this did not mean one extender was superior to the other.
• In conclusion, both extenders can be utilised effectively for cryopreservation of equine semen.