Characterization and short-term storage of Tasmanian devil sperm collected post-mortem

The Tasmanian devil is suffering from a severe population decline due to the fatal Devil Facial Tumour Disease (DFTD). The development of assisted reproductive technologies such as AI and long-term sperm storage could facilitate genetic management of captive insurance populations. The aim of this study was to characterise semen samples collected post-mortem, and to develop a suitable diluent for short-term preservation of devil sperm. Low numbers of sperm (1.33 ± 0.85 × 106 sperm per male) were extracted from the epididymides of 17 males. Devil sperm sample characteristics such as concentration and morphology were similar to other dasyurids. The most commonly observed morphological abnormalities were midpiece separation, tail curling, and tail twisting (on the axial plane). Changes in motility occurred throughout the regions of the epididymis with (mean ± SD) 29.4 ± 16.8, 46.8 ± 13.6 and 29.4 ± 18.1% of sperm exhibiting motility, and 88.9 ± 11.4, 32.0 ± 24.3 and 0.1 ± 0.2% of motile sperm exhibiting forward progressive motility in the cauda, corpus and caput, respectively. Sperm from the cauda and corpus epididymis maintained 31.7 ± 26.6 and 80.6 ± 85.9%, respectively, of initial motility after 12 h at 15 °C in a TEST yolk buffer diluent. These findings provided new information regarding devil sperm biology and short-term sperm storage; such information is necessary for future development of long-term sperm preservation methods in the Tasmanian devil.