Naphthalene-induced changes in carbohydrate metabolism in Sarotherodon mossambicus Peters (Pisces: Cichlidae)

Sarotherodon mossambicus Peters was exposed to naphthalene concentrations ranging from 7.9 to 0.92 mg/l for periods ranging from 4 days to 10 weeks and changes in glycogen, glucose, pyruvic acid and lactic acid contents of liver and muscle were studied. While glucose levels remained unaffected, major effects could be seen in the other constituents following both lethal and sublethal naphthalene treatment. Whereas glycogen and pyruvic acid levels showed considerable reduction, lactic acid levels increased markedly. These changes are indicative of a metabolic stress leading to a shift to anaerobic metabolism. The effects do not appear to be related to the feeding and growth rates of the naphthalene-intoxicated fish.