The aquatic habitats are being contaminated with heavy metals due to industrialization and other anthropogenic activities. Aquatic animals inhabiting polluted water bodies tend to accumulate many chemicals in high concentrations even when the ambient environmental contamination levels are low potentially hazardous situation for the entire food chain. The metal works industries release a good amount of heavy metals like mercury, cadmium, manganese, nickel and chromium which ultimately fall in the water bodies. Heavy metals are known to cause alterations in various tissues of fish at the biochemical level. The aim of the present study is to assess the glycogen content in gill, liver, kidney, brain and muscle of the fish Labeo rohita exposed to sublethal concentrations of nickel chloride 1/5th (high), 1/10th (medium) and 1/15th (low) of the 96 hour LC50 values for the period of 10, 20 and 30 days. The fish exposed to nickel chloride showed a decrease the glycogen level for 10, 20 and 30 days in gill, liver, kidney, brain and muscle. However, no information is on record concerning the three different sublethal concentration of heavy metal, nickel on the glycogen contents of fish. The objective of the present work was to observe the effect of nickel chloride on glycogen levels in gill, liver, kidney, brain and muscle of Indian major carp, Labeo rohita.
