Most of the living organisms derive energy by the metabolic breakdown of carbohydrates. The chief carbohydrate in the tissue is glycogen, while glucose is utilizable sugar found in the tissues and body fluids. The oxidation of glucose is mediated by catabolic pathways viz., glycolysis, Kreb’s cycle, electron transport system and hexose mono-phosphate shunt, which constitute the major segments of carbohydrate metabolism. Thus carbohydrate metabolism gained importance in physiology of animals. In the present study fresh water carp, Catla catla was exposed to heavy metals lead and chromium to study the impact of these metals on the carbohydrate metabolism of the fish. Study revealed that there was a clear deteoration of carbohydrate metabolism under the toxicity of the heavy metals lead and chromium. It was clearly observed that liver and muscle glycogen levels were decreased where as the activity of glycogen phosphorylase was increased in both the tissues studied
