Written by Jennifer Ringwelski
The goal of animal semen evaluation is to identify those ejaculates with the “best quality” and that contain sperm cells that are apparently capable of fertilizing oocytes. While semen quality parameters typically evaluated in a commercial semen center include sperm concentration, sperm motility and sperm progressive motility, these are not commonly highly correlated to fertility, specifically pregnancy rate; and, in litter bearing species, litter size. However, these measures of sperm quality can be combined with fluorescent assays to assess sperm functionality and this may result in a more comprehensive view of an animal’s fertility.
One of these assays of particular interest is sperm plasma membrane integrity, commonly referred to as “sperm viability” in commercial settings. In brief, a semi-permeable fluorescent DNA-probe is introduced into a diluted ejaculate sample. Sperm with a functional plasma membrane -or viable sperm- will not allow the stain to penetrate the membrane. Conversely, sperm with a compromised plasma membrane will absorb the stain allowing the probe to bind to the highly concentrated DNA within the cell and will be considered non-viable. Viability analysis can be completed using dual staining techniques, such as SYBER-14 and propidium iodide (PI), or by using a single stain, such as Hoechst 33258 in combination with fluorescent microscopy.
With the advancement of computer assisted sperm analysis (CASA) systems, analysis of viability can now be automated and reported in conjunction with motility, progressive motility, and automated morphometry. The Hamilton Thorne VIADENT assay, available with the IVOS II CASA system, uses a combination of visible and fluorescent illumination to identify and calculate concentration, motility, progressive motility, and sperm kinematics as well as viability, in a single analysis of stained sperm. The number of viable cells counted in relation to the total cell count is then used to calculate the percent viability.
To learn more about the IVOS II distributed exclusively by IMV Technologies in many of the world’s animal markets, and the VIADENT software and stain assays, speak with one of our global CASA experts or visit the IVOS II page of the IMV Technologies website.
The views expressed in IMV Technologies' blog do not necessarily represent the views of the IMV Technologies Group but solely those of the blog post's author.