SUBLETHAL EFFECTS OF NICKEL ON CARBOHYDRATE-METABOLISM, BLOOD AND MINERAL CONTENTS OF TILAPIA-NILOTICA

Effects of three sublethal levels (19.2, 32 and 51.2 mg L-1) of Ni on carbohydrate metabolism, hematology and mineral contents of Tilapia nilotica at 6 time intervals from 6 to 96 hr have been evaluated. Prominent dose-dependent hyperlacticemia and hyperglycemia were showed at the three Ni levels. Liver glycogen showed a general decrease at all Ni levels and muscle glycogen showed a decrease only at the two higher levels of Ni. High Levels of Ni elevated red blood cell count, hemoglobin content and packed cell volume and caused leucopenia and lymphopenia. The presence of Ni resulted in its accumulation in the blood, kidney, liver and muscle. Nickel accumulated to the greatest extent in the kidney. It had no statistical influence on the blood Cu content but considerably increased the Zn content of blood and Fe content of all the tissues investigated.