Retrograde Flushing Followed by Slicing Float-Up as an Approach to Optimize Epididymal Sperm Recovery for the Purpose of Cryopreservation in Equids.
Authors: Podico Giorgia, Canisso Igor F
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Maximising viable sperm recovery from post-mortem equine epididymides has significant implications for genetic preservation and breeding programmes, particularly when conventional collection methods are unavailable. Researchers at this institution evaluated retrograde flushing combined with slicing float-up—a two-stage harvest technique—on epididymal tissue from 28 horses and 18 donkeys, measuring sperm yield, concentration, and cryopreservation outcomes including post-thaw motility and cellular membrane integrity via flow cytometry. The sequential approach substantially improved total sperm recovery, yielding 57% more viable sperm from donkey epididymides and 31% more from horses compared to retrograde flushing alone, though donkeys consistently demonstrated higher sperm concentrations (684 versus 494 million/mL). Critically, combining these recovery techniques did not compromise post-thaw sperm quality markers—progressive and total motility, sperm membrane integrity, and mitochondrial function remained unaffected by harvest method or species. For practitioners involved in stallion and jack preservation, genetic banking, and assisted reproductive programmes, this protocol offers a pragmatic means of optimising material recovery from post-castration or deceased animals without sacrificing cryopreserved sperm viability.
Read the full abstract on PubMed
Practical Takeaways
- •Using retrograde flushing followed by slicing float-up can significantly increase sperm yield per epididymal collection without compromising post-thaw quality, making it a superior harvest strategy for equine breeding programs
- •Donkeys consistently yield higher sperm concentrations than horses; adjust expectations and protocols accordingly when working with different equine species
- •This combined technique is practical for equine practitioners involved in breeding soundness evaluations, stallion management, or preservation of genetic material from valuable animals
Key Findings
- •Retrograde flushing followed by slicing float-up increased total sperm recovery by 57% in donkeys and 31% in horses compared to single-technique approaches
- •Sperm concentration was significantly higher in donkeys (684 ± 62.9 million/mL) than horses (494 ± 50.9 million/mL)
- •Combined RF+SF technique did not negatively affect post-thaw sperm motility, membrane integrity, or mitochondrial membrane potential compared to individual techniques
- •Total sperm harvested was lower from SF alone (3.6 ± 0.7 billion) versus RF alone (10.4 ± 1.5 billion)