Computer-assisted
sperm analysis (CASA): objective assessment of sperm motility
European Network for the Dissemination of Aquaculture
RTD Information (Q5CA-2000-30105) and previously FAIR-3837, Aquaflow ref. :
TL2003-199
The assessment of fish sperm motility in fish and
mollusc hatcheries is usually based only upon subjective estimation of the
percentage of motile cells and duration of motility. However, these techniques are much less sensitive than
objective evaluation of sperm motility using computer-aided sperm analysis
(CASA). It has been proven that
CASA parameters analysed with this simple and rapid method are well
correlated with fertilisation.
Apart from laboratory conditions, where CASA gives
the opportunity to study the mechanisms of initiation, activation,
inhibition and chemotaxis (a simple response,
either positive or negative, to chemical stimuli) of sperm motility,
there are many applications of CASA analysis in aquaculture.
The sub lethal effects of pollutants that are manifested by decreased
sperm quality could be, for example, easily detected using CASA. Testing
different media used to extend sperm longevity in short-time or
cryopreservation, and the examination of the efficiency of different
spermiation stimulants demonstrate how usefulness this method is for
aquaculture applications.
The advantages of CASA in aquaculture are obviously
not restricted to fish sperm. The
recent studies have given records of usefulness of this method in monitoring
quality of sea urchin and mollusc sperm. For example, heavy metals, phenols
and very low (comparable to environmental), UV-B irradiances manifest
themselves by decreasing motility of sea urchin sperm.
Another positive feature of CASA is that videotaping
of sperm movement can be done in the field, with more detailed analysis of
videotapes being done later in the laboratory. This therefore, requires no
need to transport expensive equipment to the farm. It simply depends on the
farmer’s decision to analyse sperm quality using CASA parameters himself,
or if he prefers to invite specialists to do it for him. In the first case,
he should have the necessary equipment: a microscope with negative
phase-contrast or dark field and x10, or x20 negative phase objective, black
and white CCD camera (for example Sony, SPT-M108CE), videorecorder, TV
monitor, tapes and multi-test slides (for example 12-well slides from ICN
(Cat No. 6041205)) with cover slips and pipettes.
Ongoing experiments in this laboratory are generally
concerned with freshwater fish and mollusc sperm. The majority of the applications mentioned above are used for
monitoring of negative effects of heavy metal pollutants on salmonid and
sturgeon sperm. All experiments are carried out in close co-operation with
aquaculturists. For more information we invite you to see TL2001-014.
The project is supported by Polish Academy of
Scientific Research, Project PBZ-KBN-084/P06/2002/5.8.
For
more information, contact:
Jan
Glogowski
Institute of Animal Reproduction and Food Research
- Molecular Andrology Group - Polish Academy of Sciences
ul. Tuwima 10, 5 P.O. Box. 55
10-747 Olsztyn
Poland
E-mail: dietrich@pan.olsztyn.pl