Abstract

Post-mortem gamete rescue is a process in which gametes are collected from recently deceased animals for cryopreservation and storage in a genome resource bank. In conjunction with assisted reproductive technologies such as artificial insemination, genome resource banks containing functional gametes can serve to enhance the genetic diversity of ex situ populations and also have potential to help rescue species from extinction if catastrophic losses were to occur in the wild. In addition to serving as a source of genetic diversity for infusion into ex situ or in situ populations long after the male has died, gamete rescue samples can be integrated into longitudinal reproductive health assessments of wild populations, and may be useful for monitoring impacts of anthropogenic stressors such as environmental pollutants. For post-mortem gamete rescue in male animals, the vas deferens are ligated, then the testes, epididymides and vas deferens are excised, cooled slowly to 5–10°C during transport to the laboratory and processed for the recovery and cryopreservation of epididymal spermatozoa. Offspring have been produced on a limited basis using frozen-thawed gamete rescue sperm samples and artificial insemination in a number of domesticated and wild species (e.g., ^1-5) but there exist no reports in marine mammals. Though mammalian spermatozoa can remain viable in the epididymides and vas deferens for several hours or more after death, maintenance of sperm functionality appears to be influenced by multiple factors including medical history and post-mortem environmental conditions. This presentation will discuss methodological issues in cetaceans relating to the collection of intra-abdominal reproductive tissue along with male gamete evaluation and handling techniques for maximizing the functional capacity of cryopreserved material.

Acknowledgements

For assistance with gamete rescue and cryopreservation procedures, the authors thank staff of the SeaWorld and Busch Gardens Reproductive Research Center, as well as veterinary, curatorial and animal care staff at all SeaWorld parks, in particular Dr. Judy St Leger and Erika Nilson.

* Presenting author

Literature Cited

1.  Blash S, Melican D, Gavin W. Cryopreservation of epididymal sperm obtained at necropsy from goats. Theriogenology. 2000;54:899–905.

2.  Kusunoki H, Daimaru H, Minami S, Nishimoto S, Yamane K, Fukumoto Y. Birth of a chimpanzee (Pan troglodytes) after artificial insemination with cryopreserved epididymal spermatozoa collected postmortem. Zoo Biol. 2001;20:135–143.

3.  Bartels P, Friedmann Y, Lubbe K, Mortimer D, Rasmussen LA, Godke RA. The live birth of an eland (Taurotragus oryx) calf following estrous synchronization and artificial insemination using frozen thawed epididymal sperm. Theriogenology. 2001;55:381 (Abstr).

4.  Tsutsui T, Wada M, Anzai M, Hori T. Artificial insemination with frozen epididymal sperm in cats. J Vet Med Sci. 2003;65:397–399.

5.  Guerrero CA, Gentry G, Saenz J, Bondioli KR, Godke RA. Birth of calves after artificial insemination with cryopreserved bovine epididymal spermatozoa harvested from postmortem bulls. Reprod Fert Dev. 2009;21:105 (Abstr).