222. Sperm morphology within the testis and cauda epididymis of a Tasmanian devil (Sarcophilus harrisii)

A male Tasmanian devil, aged 6.5 years, was euthanased with intravenous pentobarbitone overdose due to the diagnosis of squamous cell carcinoma. The testes and cauda epididymes were removed immediately after euthanasia and placed into TALP-HEPES medium containing 3% BSA and dissected. Smears of the isolated sperm were made, air-dried and stained using Diff-Quik. Sperm were classified using a modification of a system originally applied to the brush-tailed possum1 as follows: (a) Immature I – head is perpendicular or greater than 45° to the tail. (b) Immature II – head forms an acute angle of 45° or less with the tail. (c) Immature III – head and tail lie in a straight line but the sperm head still has a partly expanded acrosome. (d) Mature – the head is aligned with and has a diameter similar to the tail. No motility was seen in the testicular sperm, but >60% of sperm from the cauda epididymes were motile. The stained preparations showed a significant difference in the distribution of sperm between the testis and epididymis (χ2 = 150.45, df = 3, P < 0.001), with sperm within the testis being skewed towards the earlier stages of development whereas the epididymis was skewed towards the later stages of development (Table 1). These results confirm the similarity with several other marsupials in that sperm are formed in the testis with the head at right angles to the tail but rotation of the head to become aligned with the tail is completed during epididymal transport. Work is now required to identify optimum conditions for the culture, cryopreservation and insemination of sperm from this species. (1)Cummins JM. (1976). Epididymal maturation of spermatozoa in the marsupial Trichsurus vulpecula: changes in motility and gross morphology. Aust. J. Zool. 24, 499–511.