Heavy metal, cadmium chloride induced biochemical changes in the Indian major carp Cirrhinus mrigala (hamilton)

Abstract

The fresh water fish Cirrhinus mrigala (Hamilton) was exposed to the heavy metal Cadmium chloride for 24, 48, 72, and 96 h, and the consequential LC 50 values were calculated using Finney’s probit analysis. The LC 50 values obtained for 24, 48, 72, and 96 h were 317.5, 316.5, 316.0 and 315.5 respectively. Later the fish were exposed to 96 h acute lethal and sub-lethal concentrations and the biochemical changes of glycogen, proteins, and nucleic acids of DNA, and RNA in the vital organs viz, Gill, Brain, Liver, Muscle and Kidney of the test fish were estimated and compared with the control fish. The present study revealed that Cadmium chloride is highly toxic to the test fish and the extent of toxicity increased with the increase in the exposure period. During the test period it was also observed that the fish showed erratic movement, restless, and surfacing phenomena engulfing air. A thin film of mucus was formed on the surface of gills and body. In the results of the biochemical changes it was observed that the total glycogen content and proteins decreased in all the tissue of the organs, whereas in the nucleic acid content heterogynous changes were observed. The increase in DNA content of gill may be due to hypertrophic nature of chloride cells. The results obtained in all were discussed at length with the available literature.