Doctor of Philosophy (PhD)
Animal Science (Animal, Dairy, and Poultry Sciences)
The interest in preserving endangered species has increased the amount of attention lent to the recovery of functional sperm from the epididymides of deceased males (Foote, 2000). Postmortem specimens have a finite time period before decomposition affects functionality. Determination of this “window of opportunity” to harvest and preserve epididymal sperm would be beneficial for further research in sperm preservation and assisted reproductive technologies. The objective of these studies was to determine 1) the “window of opportunity” to collect viable rat, caprine, equine and bovine epididymal sperm, 2) if epididymal sperm collected could be cryopreserved, 3) to test two common cryoprotectants for efficacy of sperm preservation, 4) to determine if bovine samples could be used to produce in vitro fertilization (IVF) embryos and 5) to establish if sperm subjected to a series of freeze-thaw cycles can maintain motility. Epididymal sperm collected from rat, caprine, equine and bovine males all maintained some level of acrosomal membrane integrity up to 96 hours postmortem. The bovine, caprine and equine sperm survived cryopreservation and exhibited greater preservation with milk-based extenders. In vitro fertilization with cryopreserved bovine epididymal sperm was not efficient but development of embryos proved limited usefulness. Finally, subjecting the bovine sperm to repeated freeze-thaw cycles proved extremely damaging and should be practiced only when absolutely necessary. Rat sperm exhibited a difference from 24 to 48 hour with a percent progressive motility (PPM) of 46 to 28%. Caprine sperm PPM and percent intact acrosomes (PIA) declined after 24 hours from 68 and 66% to 56 and 55% at 48 hours, respectively. Equine sperm exhibited a drop in PPM and PIA at 48 hour of 42 and 71% to 34 and 68% at 72 hours, respectively. Bovine sperm PPM dropped initially from 65 to 49% at 24 to 48 hours and again from 46 to 30% at 72 to 96 hours. The difference in PIA only appears between 24 and 48 hours of 77 to 65%. As stated previously, the epididymal sperm collected from the rat, caprine, equine and bovine males maintained acceptable levels of PPM and PIA up to 96 hours postmortem.
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James, Aida Nioma, "Preservation of sperm harvested from the rat, caprine, equine, and bovine epididymis" (2004). LSU Doctoral Dissertations. 1041.
Robert A. Godke