Light microscopic features and morphometry of sperm in the emu (Dromaius novaehollandiae)

Abstract

A comprehensive morphological description of emu sperm at the light microscopy level, an essential prerequisite for the routine evaluation of semen quality in this species, is not currently available. In this study sperm structure was visualized by making conventional semen smears from samples collected from the distal ductus deferens and fixed in 2.5% glutaraldehyde. This was followed by air-drying the smears and staining with a Romanowsky type stain. Examination of the smears using phase contrast illumination and a 100x oil immersion lens readily resolved the various components of the cell, namely, the acrosome, nucleus, midpiece, principal piece and endpiece. This technique was simple to use and produced consistently reproducible results. Normal emu sperm were typically filiform in appearance and closely resembled sperm of the ostrich and other non-passerine species, particularly poultry. A previously undescribed cytoplasmic appendage, associated with the 2 base of the head, was a novel morphological feature. Sperm dimensions in the emu were similar to those of other ratites. This was reflected by a head:tail ratio of 1:4 which is in accordance with the value reported for the ostrich.

Recent advances in bird sperm morphometric analysis and its role in male gamete characterization and reproduction technologies

“…Morphometric analyses of avian spermatozoa by light microscopy are, however, relatively scarce 59. Most studies have involved conventional techniques and the subjective assessment of sperm variables;6061 unfortunately, these methods can return significantly different results when performed in different laboratories or by different operators 626364.…”

“…Certainly, sperm head size would seem to subject to such effects 69. Formaldehyde,88 Hancock's solution,89 and glutaraldehyde59 have all been used in sperm assessment, with the last of these reported to reduce the cell shrinkage observed in air-dried semen smears, thus allowing greater structural detail to be observed by phase contrast microscopy 9091. In roosters, Hemacolor® returns significantly larger sperm head widths and areas than the aniline blue technique does while the latter results in greater sperm head lengths 5.…”

A morphological classification of sperm defects in the ostrich (Struthio camelus)

“…Smears were prepared from the fixed cell suspensions, air-dried for a minimum period of 24 h and stained with Wright"s stain (Rapidiff ® , Clinical Sciences Diagnostics, Johannesburg, South Africa) in Coplin jars as previously described (Du Plessis and Soley, 2014).…”

Influence of Staining Method on the Values of Avian Sperm Head Morphometric Variables

“…Yet, morphology is among the most important factors in avian sperm evaluation, and numerous light and electron microscopy studies have detailed the morphological features of normal and abnormal sperm in a number of bird species (Bakst and Howarth ; Bakst ; Tabatabaei et al. ; Du Plessis and Soley ). Indeed, detailed electron microscopy‐based information is available on the classification, measurement and description of normal and defective rooster sperm (Grigg and Hodge ).…”

“…Indeed, detailed electron microscopy‐based information is available on the classification, measurement and description of normal and defective rooster sperm (Grigg and Hodge ). Yet, information is very scarce on its morphometric assessment at the level of light microscopy (Du Plessis and Soley ). The availability of computer‐assisted light microscopic methods that could reliably and quickly determine avian sperm morphometry would be an important advance.…”