Optimization of the Thawing Protocol for Iberian Boar Sperm

Area of Science:

• Reproductive Biology
• Cryopreservation Science
• Animal Genetics

Background:

• Thawing protocols for cryopreserved sperm are underexplored.
• Improving post-thaw sperm quality is vital for sperm banks, especially for endangered Iberian pig breeds.
• Current methods lack optimization, potentially impacting genetic resource preservation.

Purpose of the Study:

• To evaluate the impact of different thawing rates on sperm quality.
• To assess modifications in thawing extender composition, including pH, cholesterol-loaded cyclodextrins (CLC), and ion chelators (EDTA, EGTA).
• To identify optimal thawing conditions for preserving sperm viability.

Main Methods:

• Sperm samples were thawed using various rates and extender compositions.
• Evaluated parameters included overall sperm motility, kinematic parameters, acrosome status, and sperm membrane integrity.
• Compared results against a control group thawed at 70 °C.

Main Results:

• The optimal thawing rate was 70 °C for 8 seconds.
• Inclusion of 12.5 mg of CLC per 500 × 10^6 spermatozoa in the thawing extender significantly improved results.
• The optimized protocol showed superior outcomes compared to the standard 70 °C thawing control.

Conclusions:

• Adapting thawing conditions, including rate and extender additives, can substantially enhance post-thaw sperm quality.
• This optimization is particularly relevant for the conservation of endangered species and breeds, such as Iberian pigs.
• The findings can be applied to improve cryopreserved samples in gene banks for biodiversity preservation.