Carbohydrate Reserves And Metal Accumulation Of The Nile Tilapia, Oreochromis Niloticus After Treatment With Heavy Metals

Abstract

This study investigated the carbohydrate reserves and metal accumulation of the Nile tilapia, Oreochromis niloticus after exposure to sublethal concentrations of heavy metals such as copper, lead and zinc for a 12-week period, using static renewable toxicity tests. The concentrations of the metals accumulated in the tissue of exposed fish were about 3-5 times higher than the concentrations detected in control fish. The accumulation of plasma glucose in O. niloticus was observed to be dose dependent. It is significantly higher (P<0.05) as the exposed period increased and it produced hyperglycaemic response in the fish. The different concentrations of the various heavy metals significantly induced stress in the animal and this subsequently reduced fish\'s muscle and liver glycogen contents. The outcome effect is impairment of carbohydrate metabolism, which caused fish physiological dysfunction.

IFE Journal of Science Vol. 9 (2) 2007 pp. 177-184