Development and evaluation of electroejaculation techniques in the Tasmanian devil (Sarcophilus harrisii)

Abstract

Electroejaculation (EEJ) has been used successfully to collect samples suitable for genome resource banking from a variety of endangered wildlife species. Ejaculates can also be used to evaluate the reproductive potential of individuals and provide information on seminal characteristics to aid in the development of sperm cryopreservation techniques. Electroejaculation techniques used for marsupial and eutherian species were tested on Tasmanian devils (n = 35). Spermic ejaculates were collected in 54% (19/35) of EEJ attempts. Spermic ejaculates were low in volume (3.9 ± 6.5 × 102 µL, range 10–3000 µL) and contained low numbers of spermatozoa (3.3 ± 7.8 × 103 spermatozoa per ejaculate, range 6–33 000). The osmolality and pH of presumptive urine-free ejaculates were 389 ± 130 mOsm kg–1 (range 102–566) and 7.0 ± 0.9 (range 6.0–8.0), respectively. Prostatic bodies were observed in 79% (26/33) of ejaculates. Episodic fluctuations in serum testosterone concentrations were not detected during the EEJ procedure (P > 0.05). Increases observed in serum cortisol concentrations during EEJ were less (P < 0.05) than those observed after an adrenalcorticotropic hormone challenge and diurnal variation suggested that cortisol concentrations are greater during the day than at night (P < 0.05). This information can be used to provide range values for the future examination of basic endocrine responses and the adrenal–pituitary axis of this species. This study also demonstrated that spermatozoa-rich devil electroejaculates are more difficult to obtain and poorer in quality than those of other marsupials.