In order to see the changes in Protein and Carbohydrate content in Liver and Intestine of oreochromis mossambicus, the tissue were stained with Mercuric Bromophenol Blue (MBB) and Periodic Acid Schiff’s reagent (PAS). Observations of the histochemical studies were dependent entirely upon the intensity of the coloured chemical constituents. The amount of protein in liver was found decreased in a dose dependent manner with increase in concentration after 10 and 20 days for Cadmium sulphate, as the stains were lighter in hepatocytes. Similarly, the amount of carbohydrate in liver showed marked decrease in carbohydrate content after 10 days. The purple colour of the stain was still lighter showing decrease in carbohydrate content after 20 days. In terms of carbohydrate utilization, the effect showed less carbohydrate content. The intestine section from control fish showed good intensity of blue colour in the area specific to endothelial cells and villi. The amount of protein decreased in a dose dependent manner with increase in concentration of cadmium and the intensity of blue colour was still light and in no way comparable to control for all the tested concentration. In case of carbohydrate content, villi and microvilli took good amount of stain and no marked changes were observed after 10 and 20 days of exposure.
