view - Department of Reproduction, Obstetrics and Herd Health

CHAPTER 1.1
al., 2002), boars (Maes et al., 2003; Vyt et al., 2004) rams (Fukui et al., 2004), bulls (Hoflack et al.,
2005), and mice (Tayama et al., 2006)]. The newest version of the SQA (version V) was initially
developed for human samples as well and later on adapted for different animal species, namely bulls,
boars, stallions and turkeys. Specific devices for rams and roosters are in development. The SQA is
ready to use after delivery and does not require (or allow) user specific settings, as such reducing a
large potential source of bias (Hoflack et al., 2005).
14
Objective motility analysis: Computer Assisted Sperm Analysis
The best known way to objectively analyze sperm motility is analysis by means of a CASA
system. The first CASA system was introduced over 30 years ago, and has been used ever since in
human and veterinary andrology laboratories. By equipping a microscope with a camera, the sperm
cells are visualized and the actual sperm tracks can be analyzed after sperm cell recognition. The
latter can be achieved either based on the number of pixels and intensity or, in newer versions, by
means of fluorescent dyes. This technique facilitates sperm recognition and allows CASA analysis of
(post thaw) samples containing egg yolk particles (Tardif et al., 1998) or debris for example after
obtaining epididymal sperm in cats (Filliers, personal communication). The major advantages of CASA
systems are, amongst others, the good repeatability and the absence of subjectivity. Nevertheless,
standards for analysis need to be established first, since different technical settings and sample
preparations have been shown to influence the outcome of CASA analysis (Table 1). The impact of
different technical settings (frame rate and number of frames analyzed) and procedures
(temperature, concentration, diluents and chamber) have been studied for different species (Contri
et al., 2010; Lenz et al., 2011; Rijsselaere et al., 2003). Also, the motility settings may have an
influence on the CASA outcome as well. Based on low and medium average pathway velocity (VAP)
cut-off values and on straightness (STR), spermatozoa are graded. In literature, a plethora of settings
is used (Table 2). Not only is there a lack of agreement in the cut-off values used by different
research groups, also the description of these values is not uniform for CASA systems from different
companies.
A comparable lack of standardization can be found in the chambers used to analyze the
motility of a semen sample. Although the effect of the counting chamber was already described in
2001 (Iguer-ouada and Verstegen, 2001), different brands and types of chambers are used. The most
frequently used chambers are a 20 µm deep Leja chamber (Waite et al., 2008; Ortega-Ferrusola et al.,
2009; Len et al., 2010), a 20 µm deep Cell-Vu (Almeida and Ball, 2005; Glazar et al., 2009; Spirizzi et
al., 2010) and the 10 µm deep reusable Makler chamber (Kavak et al., 2003; Johannisson et al., 2009).