USE OF COMPUTER-ASSISTED SPERM ANALYSIS (CASA) FOR MONITORING THE EFFECTS OF POLLUTION ON SPERM QUALITY OF FISH - APPLICATION TO THE EFFECTS OF HEAVY-METALS

Computer assisted sperm analysis (CASA) has been used to analyse the e ffects of cadmium and zinc on the motility of fish sperm treated eithe r for 24 h after partial dilution in an extender, or during the final dilution step on the microscope stage during video recording. The prog ressive motility of catfish sperm, which was not affected by storage f or 24 h, was decreased after exposure to 100 ppm cadmium or 2000 ppm z inc in extender for 24 h. Only 1000 ppm cadmium or 2000 ppm zinc had a ny effect on motility when added to sperm at the final dilution stage. These results suggest that concentrations of cadmium which have been found to be present in fish gonads as a result of bioaccumulation from the water or diet may decrease the motility of sperm during maturatio n or storage in the testis. Cadmium toxicity was significantly decreas ed in the presence of an equal amount of zinc, suggesting an equilibri um between zinc and cadmium at binding sites in the sperm. Computer as sisted sperm analysis is shown for the first time to provide a rapid a nd quantitative measure of the effects of environmental pollutants on the quality of fish sperm. It is suggested that the methodology descri bed may form the basis for a standard toxicity test to assess the pote ntial hazards of environmental pollutants on reproduction.