MORPHOLOGY AND ORIGIN OF SPERM NECK DEFECTS IN THE EMU, DROMAIUS NOVAEHOLLANDIAE

摘要

The head-base/neck region of both mammalian and avian sperm has been identified as a potentially vulnerable area prone to a variety of defects. Anomalies in this region are reported to originate during spermiogenesis or may manifest during the passage of sperm through the excurrent duct system where factors such as vigorous flagellar movements or adverse osmotic conditions may also contribute to their formation. Recent studies on emu sperm revealed that a large percentage of sperm defects occurred in the head-base/neck region. This study describes the basic morphology of these defects and provides evidence pointing to a common origin of the anomalies during spermiogenesis. Semen samples were collected from the distal ductus deferens of 15 adult emus slaughtered commercially during the mid-breeding season and immediately fixed in 2.5% phosphate-buffered glutaraldehyde. Smears for light microscopy (LM) were prepared from the fixed samples, stained with Wright's stain and examined using a 100x oil immersion objective. Semen samples were also routinely prepared for transmission (TEM) and scanning electron microscopy. Testis samples were processed conventionally for TEM.