Improved cryopreservability of stallion sperm using a sorbitol-based freezing extender

Area of Science:

• Reproductive Biology
• Cryobiology
• Equine Science

Background:

• Cryopreservation of stallion semen often results in diminished post-thaw sperm quality.
• Sugars are crucial components in freezing extenders, functioning as non-permeating cryoprotectants.

Purpose of the Study:

• To evaluate and compare the efficacy of glucose, fructose, and sorbitol in stallion semen freezing extenders.
• To assess the impact of different monosaccharide sugars on post-thaw sperm quality and fertility.

Main Methods:

• Semen from six fertile stallions was cryopreserved using extenders with glucose, fructose, or sorbitol.
• Post-thaw analysis included sperm motility, viability, acrosome integrity, plasma membrane functionality, and longevity.
• Fertility was assessed via artificial insemination using semen cryopreserved with sorbitol.

Main Results:

• Sperm quality significantly decreased after freezing and thawing (P < 0.05).
• Fructose was less effective in protecting sperm during cryopreservation compared to sorbitol and glucose (P < 0.05).
• Sorbitol-based extenders demonstrated superior preservation of sperm motility, viability, acrosome integrity, and plasma membrane functionality compared to glucose and fructose, especially at 10 min post-thaw.

Conclusions:

• Different sugars exhibit varying cryoprotective abilities for stallion sperm.
• An extender utilizing sorbitol as the primary sugar enables successful cryopreservation of equine sperm.
• Sorbitol-containing extenders yield better frozen-thawed sperm quality than those with glucose or fructose.