The use of a hypo-osmotic swelling (HOS) test on sperm of the pig (Sus scrofa domesticus), emu (Dromaius novaehollandiae), Asian elephant (Elephas maximus), hamadryas baboon (Papio hamadryas hamadryas), and central rock rat (Zyzomys pedunculatus)

SUMMARYA hypo-osmotic swelling test using TALP-HEPES medium over a range of 50 to 300 mOsm/kg was applied to sperm from domestic and endangered species. Maximal responses of curling of the sperm tails were seen over a range of osmolalities for epididymal sperm from the pig (100 mOsm/kg), hamadryas baboon (range 50-125 mOsm/kg), and central rock rat (range 50-100 mOsm/kg), and the ejaculated sperm from the emu (50 mOsm/kg) and the Asian elephant (range 75-150 mOsm/kg). A solution of TALP-HEPES medium at 100 mOsm/kg would be suitable to obtain the maximal response in this range of mammals tested, though it would need to be diluted to at least 50 mOsm/kg when testing the viability of the emu sperm.