Ptk. Woo et al., THE EFFECTS OF SHORT-TERM ACUTE CADMIUM EXPOSURE ON BLUE TILAPIA, OREOCHROMIS-AUREUS, Environmental biology of fishes, 37(1), 1993, pp. 67-74
Disease-free blue tilapia, Oreochromis aureus, exposed to cadmium (0.5
ppm and 10 ppm) showed very significant and dramatic decrease in food
consumptions. Food consumptions returned to near normal 21 days after
fish were returned to cadmium-free water. Along with anorexia there w
ere decreases in body weights during the period when fish were exposed
to cadmium. Fish in cadmium-free water that were pair-fed to cadmium-
exposed fish (0.5 ppm) did not gain weight but there were no decreases
in body weights. Cadmium was still in tissues 34 days after the fish
were placed in cadmium-free water and the accumulation was highest in
the kidney; this was followed by liver, brain, gill filaments and musc
les. The accumulations of the heavy metal (in kidneys and gills) were
significantly higher in fish exposed to high than low cadmium levels.
There were no differences in complement levels (haemolytic acitivity)
in cadmium-exposed and cadmium-free fish. However, cadmium-exposed fis
h did not produce detectable haemagglutinating antibodies against shee
p red blood cells while cadmium-free fish responded well to the antige
n. The anorexia in cadmium-exposed fish contributed to the depression
in antibody production.