Stress Responses of Biomolecules and Dehydrogenase Activity in the Tissues of Labeo rohita against Pollutant Load in the Lakes of Bangalore

The physico-chemical characteristics of the aqueous phase have direct influence on the metabolic activity of aquatic biota, in general and fish in particular. In the present investigation, water samples from selected water bodies, viz., Hebbal fish farm (control site), Vengaiah lake (receiving domestic sewage - Lake A) and Yellamallapa Chetty lake (receiving industrial effluents and drainage water - Lake B) were assessed for detection of their pollution status. Simultaneously, the muscle and gill tissue of fresh water fish, Labeo rohita reared in these water bodies, were excised and biomolecules (protein, glycogen and cholesterol) and dehydrogenases (succinic - , lactic- and malic -dehydrogenases) were subjected to analysis for their level and activity. The results obtained showed reduction in the level of protein and glycogen and a corresponding increase in cholesterol level in tissues of fish sampled from lake B when compared to those from lake A and control ones. A significant increase in lactic dehydrogenase activity with a marginal decrease in the activity of succinic and malic dehydrogenase was observed in both muscle and gill tissues of fish from lake B and an insignificant variation in those from lake A in contrast with control ones. Such changes in the biological systems can be correlated with the water parameters with the help of chemical processes. Stress response due to pollutant load in the mentioned water body in terms of fluctuations in biomolecule content and dehydrogenases actvity in the test fish resulted in variation in its metabolic pathways.