Post-thaw Addition of Caffeine and/or Pentoxifylline Affect Differently Motility of Horse and Donkey-Cryopreserved Spermatozoa.

The study investigates the impact of adding caffeine and/or pentoxifylline post-thaw on horse and donkey’s frozen sperm motility. It explores whether these substances can enhance sperm activity in horses and donkeys, while considering differences between the two species in response to these compounds.

Objective and Methodology

• The main goal of the study was to determine if the motility of horse and donkey’s frozen-thawed sperm could be improved by introducing caffeine and/or pentoxifylline post-thaw. This was assessed based on a series of motility parameters.
• The study employed frozen sperm samples from 14 different horses and seven donkeys. Once thawed, the samples were diluted in a milk-based extender to make distinct concentrations of the control, caffeine, pentoxifylline, and a combination of caffeine and pentoxifylline.
• Assessments of the samples were carried out immediately after thawing and again at sixty and one hundred and twenty minutes of incubation at a stable temperature of 37 degrees Celsius.

Findings

• For horses, it was observed that the overall motility was significantly lower in control samples, as compared to those involving the use of caffeine and pentoxifylline.
• However, in case of donkey sperm samples, no remarkable differences were found between the control and treated samples.
• During the first hour of incubation, all parameters showed more decrease in horses than in donkeys, with the sole exception of lateral sperm head displacement.
• Post-thaw motility and velocity decreased more quickly in horses than in donkeys.

Conclusions

• The study offers evidence that post-thaw addition of caffeine and pentoxifylline led to an increase in the proportion of active sperm only in horses, and not donkeys.
• The findings suggest species-specific responses to these compounds. The enhancement of post-thaw sperm motility in horses may prove beneficial in both in vivo and in vitro pregnancy rates. However, further studies are required to confirm this possibility.