Accumulation of lead and effects on total lipids and lipid derivatives in the freshwater fish Anabas testudineus (Bloch)

Abstract

Exposure of a freshwater fish to several sublethal concentrations (1.25, 2.50, 5.00, 10.00, and 20.00 mg/liter) of lead for a period of 30 days showed significant accumulation of lead in the blood and tissues. Lead bioaccumulated in the study showed organ-specific distribution, with high levels in the blood followed by the kidney, gill, liver, and brain and comparatively lesser amounts in the ovary and muscle tissues. The lead accumulation in tissues was found to increase with lead in water up to a concentration of 5 mg/liter, and at concentrations of 10 and 20 mg/liter the lead accumulation in the tissues, although indicating an increase, was not proportional to the concentration in water. Exposure of the freshwater fish Anabas testudineus to a sublethal (5 ppm) concentration of lead nitrate for a period of 30 days during the preparatory phase of its annual reproductive cycle reduced the total lipids, phospholipids, and cholesterol levels in the liver and ovary tissues while the free fatty acid levels were increased and lipase activity was elevated. All the parameters in the blood were found to increase. These results suggest that lead nitrate affects the lipid metabolism of the fish and this may reduce the fecundity of the fish since lipids are known to play an important role in teleost reproduction as an energy source and a precursor of steroids.