Cholesterol-Loaded Cyclodextrin Addition to Skim Milk-Based Extender Enhances Donkey Semen Cooling and Fertility in Horse Mares.
Authors: Segabinazzi Lorenzo Garrido Teixeira M, Scheeren Veronica Flores da Cunha, Freitas-Dell'Aqua Camila de Paula, Papa Frederico Ozanam, Alvarenga Marco Antonio, Dell'Aqua José Antônio, Canisso Igor Frederico
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Cholesterol-Loaded Cyclodextrin in Donkey Semen Extenders Cooled donkey semen exhibits poor fertility outcomes when used for artificial insemination in horse mares, largely due to sperm membrane damage during storage. Researchers compared standard skim milk-based extender against the same formulation supplemented with cholesterol-loaded cyclodextrin (CLC) across two experiments: the first assessed sperm viability parameters (motility, plasma membrane integrity, and mitochondrial function) at 0, 24, and 48 hours post-cooling using computer-assisted semen analysis and flow cytometry; the second evaluated conception rates in 15 mares over two oestrous cycles following artificial insemination with 24-hour cooled semen. Whilst baseline sperm quality was comparable between extenders, the CLC-supplemented extender maintained superior total motility, progressive motility, rapid motility, and cellular membrane integrity at both 24 and 48 hours, with mares inseminated with CLC-extended semen achieving a conception rate of 47% compared to only 13% for standard extender. These findings suggest that incorporating cholesterol-loaded cyclodextrin into skim milk extenders offers meaningful practical benefit for donkey-to-mare breeding programmes, though further validation in clinical field conditions and application to jennies remains necessary before widespread adoption.
Read the full abstract on PubMed
Practical Takeaways
- •When performing donkey-to-horse artificial insemination with cooled semen, using SKM-CLC extender substantially increases conception rates (47% vs 13%) compared to standard skim milk extenders
- •SKM-CLC extended semen maintains superior sperm quality parameters through 48 hours of storage at 5°C, potentially allowing more flexible breeding scheduling
- •This technique may be particularly valuable for breeding programs using jackstock on mares, though results should be validated in clinical field conditions before widespread adoption
Key Findings
- •Semen extended with SKM-CLC demonstrated superior total motility, progressive motility, rapid motility, plasma membrane stability, and mitochondrial membrane potential compared to SKM alone at 24 and 48 hours post-cooling (P < 0.05)
- •Mares inseminated with SKM-CLC extended donkey semen had a conception rate of 47% (7/15 cycles) versus only 13% (2/15 cycles) with SKM-only extender (P < 0.05)
- •Cholesterol-loaded cyclodextrin addition to skim milk extender significantly improved cooling ability and reproductive fertility outcomes of cooled donkey semen used in horse mares