High concentration of heavy metals or long time exposure to low concentrations of these metals
can usually decrease the hematological indices in fish. Therefore the aim of this study was to indicate
changes in hematology and serum chemistry of common carp (cyprinus carpio) after low cadmium
concentration exposure. 60 apparently healthy common carp (mean weight of 700g) divided in two
groups and transfred to 1000 liter indoor fiberglass tanks under controlled conditions. Treatment group
was exposed to low concentration of cadmium (30ppb). Blood were exsanguinated randomly from 5
fish in each group through the caudal vein at days 15 and 30 of exposure. The hematological and
biochemical parameters (WBC, RBC, different count, hematocrit, total protein, albumin and globulin
concentrations, albumin: globulin ratio, LDH, ALT, and AST) were determined. Results revealed that
WBC counts decreased significantly on the 15th day of exposure (p<0.05). Furthermore, WBC counts
decreased significantly on the 30th day of exposure (p<0.05). The levels of LDH after day 30 of
exposure, significantly increased in the test group compared to the controll. In the test group, LDH
levels significantly increased at the 30th day of exposure. No significant differences have been
observed between control and test groups in respect to the other parameters. This study showed that
the exposure time for sublethal concentration of cadmium is an important factor for increasing the
LDH levels in common carp.
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