Stallion sperm freezing with sucrose extenders: A strategy to avoid permeable cryoprotectants.

This research study investigated the usage of sucrose-based extenders with bovine serum albumin (BSA) for the cryopreservation of stallion sperm, aiming to find an alternative to traditional permeable cryoprotectants. The results indicate that sucrose 100mM combined with 1% BSA can effectively preserve stallion sperm, maintaining sperm kinetic parameters and plasma membrane integrity without the need for permeable cryoprotectants.

Objective and Methodology

• The objective of the study was to test the efficacy of different concentrations of sucrose-based extenders in combination with bovine serum albumin (BSA) in preserving stallion sperm without the use of permeable cryoprotectants.
• Semen samples were collected from six stallions, totalled 16, and were slowly cooled, filled into 0.5 mL straws and frozen in nitrogen vapor.
• Different concentrations of sucrose with 1% BSA (0, 50, 100, 250, 350, and 450 mM) were tested as extenders for the semen samples.
• The sperm kinetic parameters, the plasma and the acrosome membrane integrity were analysed post-thawing and statistically compared amongst the different treatments.

Results from Experiment 1

• Sucrose extenders containing 100mM (S2) provided improved results for most of the actions displayed by the sperm cells, as determined by the sperm kinetic parameters.
• The integrity of the plasma membrane remained consistent across the treatments, except in the cases where sucrose was used in concentrations of 50 and 250 mM. In these cases, integrity was reduced when compared to samples preserved with other sucrose concentrations.

Experiment 2 and Overall Conclusion

• In the second experiment, the best performing sucrose extender (S2) was pitted against a traditional extender that utilized glycerol as a permeable cryoprotectant.
• The results showed that the S2 extender resulted in fewer sperm with denuded acrosomes, indicating better preservation of the sperms’ functional and structural integrity.
• The kinetic parameters, measures of the activity and movement characteristics of the sperm, were also found to be in greater values when S2 was used.
• No significant differences were observed for the other parameters studied in this research between the traditional and the S2 extenders.
• Thus, the study concluded that stallion sperm could be effectively frozen using sucrose 100mM combined with 1% BSA as an alternative to prevalent permeable cryoprotectants, without a detriment to the preservation of sperm integrity.