Oral Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

Remarkable longterm viability of chilled koala spermatozoa (#45)

Bridie Schultz 1 , Jennifer Seddon 2 , Stephen Johnston 1
  1. The University of Queensland, Brisbane, Queensland, Australia
  2. School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia

The inability to cryopreserve koala spermatozoa limits our current capacity to maintain the genetic diversity of future koala populations by means of assisted breeding technologies (ABT). Consequently, our research has therefore additionally focused on the chilled preservation of koala semen samples at 5°C. Using this methodology, our group has been successful in producing koala pouch young following artificial insemination of koalas with a chilled semen sample held for 72 hours post collection; however, the ideal application of this ABT would be to have the ability to extend this chilled preservation to 33 days, or the length of a koala oestrous cycle. In this presentation, we shall report data based on electro-ejaculated semen samples processed using a range of chilled storage protocols to demonstrate the remarkable survivability (motility, plasma membrane integrity, mitochondrial membrane potential and DNA fragmentation) of koala sperm for up to 45 days post-collection. This period of chilled storage substantially exceeds the capacity of any other known mammalian sperm to survive outside the body without cryopreservation. This finding has major implications in the management of captive and wild koalas with respect to ABT, particularly in regard to processing samples for detection of disease, semen transport nationally and internationally and negating the need for synchronising semen collection to the onset of oestrus. Our next step will be to test the fertility of this long term chilled koala semen samples by incorporating it into a koala artificial insemination program.