The world-first no-chill stallion sperm extender, SpermSafe™, is now available for commercial use in Australia.
The traditional sperm storage methods of chilling and cryopreservation can inflict severe damage to sperm cells, so much so, that cells have a reduced lifespan once warmed up, and fertility is markedly reduced. Now, researchers from the University of Newcastle have developed a solution to this problem; a 17 °C sperm storage medium, SpermSafe™,that maintains sperm viability and fertility for at least 7 (and up to 14) days, without inflicting cold shock.
Dr Zamira Gibb and Dr Aleona Swegen carried out extensive research to firstly understand how stallion sperm cells metabolise energy , and then to identify the nutrients, antioxidants, and storage conditions required for optimal longevity [2-5]. During storage, sperm cells are actively metabolising, and in doing so, produce a great deal of harmful reactive oxygen species and waste products [1, 2]. Following repeated experimentation, these researchers devised the optimal formulation that works to neutralise these toxic by-products, thereby supporting sperm longevity. The result has been the development of a synthetic sperm medium that maintains cell motility, viability, and fertilising ability of cells up to 14 days . The first foal bred using the sperm extender was born on Christmas Day 2018, with many more on the ground to date.
As an alternative to traditional semen storage methods, SpermSafe™ is more cost-effective, less labour-intensive, and less invasive for mares―offering greater flexibility in insemination regimens. SpermSafe™ is free of any biological materials, such as egg or milk, thereby eliminating the biosecurity threat that accompanies international importation, and reducing the risk of processing delays at international borders. Furthermore, this protein-free formulation produces significantly less breeding-induced endometritis compared to AI with frozen semen.
Following collection, semen should be diluted (1:1) in any commercial milk-based extender.
1. Gibb, Z., Lambourne, S.R., and Aitken, R.J. (2014) The Paradoxical Relationship between Stallion Fertility and Oxidative Stress. Biology of Reproduction. 91 (3): p. 77.
2. Gibb, Z., Lambourne, S.R., Curry, B.J., Hall, S.E., and Aitken, R.J. (2016) Aldehyde Dehydrogenase Plays a Pivotal Role in the Maintenance of Stallion Sperm Motility. Biology of Reproduction. 94 (6): p. 133.
3. Swegen, A., Lambourne, S.R., Aitken, R.J., and Gibb, Z. (2016) Rosiglitazone Improves Stallion Sperm Motility, ATP Content, and Mitochondrial Function. Biology of Reproduction. 95(5): p. 107.
4. Gibb, Z., Lambourne, S.R., Quadrelli, J., Smith, N.D., and Aitken, R.J. (2015) L-Carnitine and Pyruvate are Prosurvival factors During the Storage of Stallion Spermatozoa at Room Temperature. Biology of Reproduction. 93 (4): p. 104, 1-9-104, 1-9.
5. Gibb, Z., Holt, B., Swegen, A., Lambourne, S.R., and Aitken, R.J. (2017) Mitochondrial permeability transition pore formation during chilling and cryopreservation of stallion spermatozoa, in 48th Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology. Perth, WA, Australia. p. 90.
6. Gibb, Z., Clulow, J.R., Aitken, R.J., and Swegen, A. (2018) First Publication to Describe a Protocol for the Liquid Storage of Stallion Spermatozoa for 7 Days. Journal of Equine Veterinary Science. 66: p. 37-40.
Prior to Use:
1. Upon arrival; store in -20 ⁰C freezer
2. Prior to use; reconstitute product by filling to 50 mL mark with the supplied sterile injection water or MilliQ water
Following Semen Collection:
1. Dilute semen 2:1 with warm milk-based extender (such as EquiPlus, INRA96, or Kenneys), and allow to cool to room temperature.
2. Centrifuge extended semen as per usual protocol
3. Resuspend sperm pellet in reconstituted RT SpermSafe™ medium to a final sperm concentration between 20 and 50 million sperm/mL
4. Store and ship in flat-bottom specimen pots at 17 ⁰C (Note: Do not use semen syringes for storage)
5. Load into semen syringe immediately before insemination, ensuring semen is not left in the syringe for more than a few minutes
N.B. Use reconstituted product within 2 days and store at 4 ⁰C between use.
DO NOT REFREEZE!