chapter 3 - RiuNet

CHAPTER 1
2005) and we already know it is necessary to use hormones to induce
ovulation and spermiation to overcome the lack of normal spawning stimuli
in captivity (Asturiano et al., 2005; Pérez et al., 2008). It is particularly
advantageous to stimulate the spermiation of male eels so that sperm is
available in a short time and in high volume (Gallego et al., 2012). In this
respect, knowledge of how to manipulate and preserve eel sperm is
essential (Peñaranda et al., 2008, 2009 and 2010) and a reliable and
standardized method to analyse its quality is needed.
The evaluation of sperm motility and other kinetic parameters like
curvilinear, straight line, and average path velocities, and morphology, is an
essential tool in the examination of sperm quality in many fish species (Liu
et al., 2007; Marco-Jiménez et al., 2008; Gallego el at., 2012), including the
European eel (Gallego el at., 2012; Marco-Jiménez et al., 2006; Asturiano et
al., 2007). Despite the fact that for many years optic microscopes have
conventionally been used to carry out analyses and evaluations, it is
considered subjective method and great variations have been reported
(Coetzee et al., 1999). According to Verstegen et al. (2002), when subjective
optical microscopic evaluation is used in humans and animals, variations of
30% to 60% have been reported in the estimation of the motility
parameters of the same ejaculates. The computer assisted sperm analysis,
or CASA, has been used by an increasing number of researchers worldwide
and provides an objective, rapid, and multiple-parameter assessment of
sperm quality.
To make it possible to compare the results obtained by different
laboratories, all studies that use CASA must describe its methodology very
clearly, particularly concerning image acquisition rate, track sampling time,
number of cells sampled, type and depth of the chamber used, software
name, microscope optic and magnification, etc. (Castellini et al., 2011; Soler
et al., 2012; Rosenthal et al., 2009). Unfortunately, in most publications,
details of these parameters are not provided, thus reducing the possibility
of comparing the results of different laboratories. Furthermore, because
there are many different configurations and methods of using CASA, it is
important to establish standard methods of enhancing the reliability,
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