Sperm viability, motility and morphology in emus (Dromaius novaehollandiae) are independent of the ambient collection temperature but are influenced by storage temperature

摘要

A protocol for storage of emu semen >6 h has not yet been optimized. The objective was to determine: a) whether sperm quality was adversely affected by sudden exposure to low temperatures (5, 10 and 20 degrees C) during collection; and b) the effects of three storage temperatures (5, 10 and 20 degrees C) on survival of emu sperm. In two experiments, each repeated three times on alternate days, ejaculates were diluted 1:1 with precooled (5, 10, or 20 degrees C) UWA-E3 diluent and stored for up to 48 h. Collection temperature, or interaction with either the storage time or storage temperature, had no significant effect on sperm viability, motility, or morphology. Mass Motility Score (2.91-3.27 +/- 0.26, mean +/- SEM), and percentages of live (72.4-76.2 +/- 2.4) and morphologically normal sperm (63.3-64.5 +/- 2.3) were comparable among collection temperatures. Conversely, storage temperature and storage time affected (P < 0.05) sperm viability, motility, and morphology. After storage for 48 h, percentages of viable, normal, and motile sperm were higher (P < 0.001) at 5 degrees C (58.7% +/- 1.1, 44.7% +/- 1.3, and 50.7% +/- 4.9, respectively) and 10 degrees C (62.6% +/- 1.1, 54.1% +/- 1.3, and 60.4% +/- 4.9) than at 20 degrees C (27.6% +/- 1.1, 20.1% +/- 1.3, and 25.9% +/- 4.9). Beyond 6 h of storage, the percentage of abnormal sperm was higher (P < 0.001) for storage at 5 degrees C compared to 10 and 20 degrees C. After 48 h, bacterial counts were considerably higher at 20 degrees C compared to 5 and 10 degrees C (P < 0.001). The pH of stored sperm suspension remained unaffected at 5 and 10 degrees C, but at 20 degrees C declined to 6.5 +/- 0.03 after 24 h (P < 0.05) and to 6.0 +/- 0.03 after 48 h (P < 0.001). We concluded that emu semen could be collected at low ambient temperatures (5-20 degrees C) without compromising us in vitro storage duration and that semen quality during storage for 48 h was better if it was stored at 10 degrees C than at 5 or 20 degrees C. (c) 2012 Elsevier Inc. All rights reserved.