Subacute stress induced by sumithion on certain biochemical parameters in Oziotelphusa senex senex, the fresh-water rice field crab.

Healthy crabs (Oziotelphusa senex senex) were exposed to 3 concentrations of sumithion, with a control group over a 30-day period. The glycogen content of the hepatopancreas was depleted on acute exposure but was elevated after acclimatization. The glycogen phosphorylase activity was elevated on acute exposure, whereas phosphorylase activity decreased after acclimatization. The increase in phosphorylase activity and the decrease in glycogen content indicated increased glycogenolysis at tissue level after acute exposure but on acclimatization the tissue glycogenolysis appeared to be suppressed. Sumithion was found to decrease the activity levels of SDH and MDH and to elevate LDH. The increase in LDH and the decrease in SDH and MDH in the hepatopancreas indicated the development of anaerobic conditions at tissue level in the stressed crabs. In general, acclimatization to a toxic solution seems to result in the elevation of the synthetic phase of carbohydrate metabolism.