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M. Venkata Chandrudu ¹, K. Radha krishnaiah ²

Affiliations
1 Department of Zoology, Sri Rayalaseema University, Kurnool A.P., IN
2 Department of Zoology, Sri Krishnadevaraya University, Ananatpur A.P., IN

Abstract

The levels of Na+, K+ and Ca2+ ions and the activities of Na+-K+, Mg2+ and Ca2+ ATPases were estimated in the ctenidium, mantle, hepatopancreas and foot of the freshwater mussel,L.maarginalis and gills, kidney, liver and muscle of the freshwater fish, L.rohita on exposure to a subacute concentration of cadmium (0.7mg/l) at days 10, 20 and 30. The levels of all the ions and the activity of ATPases increased in all the organs of the mussel at all the days of exposure to subacute concentration; but in the organs of fish an increase was observed only at day 10 and 20 with a decrease of them at day 30. Among the exposure periods, the elevation was gradually recovered over time of exposure in the organs of mussel, in the order: day 10 > 20 > 30, whereas in the organs of fish though the elevation was more at day 10 and less at day 20, but the levels and associated ATPases significantly decreased at day 30. In between the two animals, the elevation in the mussel gradually suppressed and reached to normal at day 30; whereas in fish the initial increase in the levels of ions and ATPases lead to a decrease of them at day 30. The results indicated decreased uptake of ions in both the animals exposed to subacute concentration due to the suppression of energetics and suppression of ATPases, the mussels could maintain the normal state of ionic balance on prolonged exposure to subacute cadmium stress; but the fish exhibited susceptibility.

Keywords

lamellidens Marginalis, Labeo Rohita, Cadmium, Subacute Concentration

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M. Venkata Chandrudu ¹, K. Radhakrishnaiah ¹

Affiliations
1 Department of Zoology, Sri Krishnadevaraya University, Anantapur-515 003, A.P., IN

Abstract

Histopathological studies would help in evaluating the extent of damage caused to the tissues under stress. Hence, in the present study an attempt has been made to observe the structural changes in the hepatopancreas and foot of the mussel Lamellidens marginalis exposed to acute (11.0mg/L) and subacute (1.10mg/L) concentrations of cadmium. The changes are observed at day 1 and day 3 in acute concentration and day 10 and 30 in subacute concentration, one at short- term and the other at long-term exposure. In hepatopancreas enlargement of intertubular area, cell necrosis and the formation of sinuses and in foot loss of connective tissue, vacuolization, disarrayed fibres and nuclear pyknosis were seen on exposure to acute concentration of cadmium at day 1. Similar changes with mild degree of recovery were observed at day 3. In subacute concentration some degenerative changes like mild tubular atrophy and cell necrosis in hepatopancreas and fibrillation, intermuscular oedema and pyknotic nuclei in foot of mussel were observed at day 10, however, at day 30 the tissues appeared more or less similar to those of controls with insignificant changes.

Keywords

Heavy metals, Cadmium Toxicity, Lamellidens marginalis, Hepatopancreas, Histology, Degenerative changes, Cell Necrosis, nuclear pyknosis, Fibrillation.

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M. Venkata Chandrudu ¹, A. Sreenivasa Reddy ¹, K. Radhakrishnaiah ¹

Affiliations
1 Department of Zoology, Sri Krishnadevaraya University, Anantapur-515 003, A.P, IN

Abstract

The levels of pyruvate and lactate, and the activities of succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) were estimated in the organs of freshwater mussel Lamellidens marginalis and fish Labeo rohita at days 10, 20 and 30 after exposure to the subacute (0.7 mg/L) concentration of cadmium. A decrease was observed in succinate dehydrogenase (SDH) activity along with a corresponding decrease in pyruvate level with an increase in lactate dehydrogenase (LDH) activity and lactate level in ctenidium, mantle, hepatopancreas and foot of the mussel and in the kidney, liver and muscle of the fish at all the days of exposure. Interestingly, an increase was observed in SDH activity and pyruvate level with a decrease in LDH activity and lactate levels in the gills of the fish. Among the exposure periods, either the percent suppression or elevation progressively recovered and reached to near normal over time of exposure in the order: day 10>20>30 in the organs of mussel. Whereas, in the organs of fish it was in the order: day 10>20<30. Thus, between the two groups of animals, either the percent suppression or elevation was progressively recovered over time of exposure in the organs of mussel, but the fish exhibited a little recovery at day 20 with a significant fall at day 30. These results indicated an adaptive ability to subacute concentration of cadmium in the organs of mussel by normalizing the oxidative and glycolytic pathways on prolonged exposure; whereas the fish exhibited susceptibility due to the suppression of oxidative metabolism and increased dependency on anaerobic glycolysis.

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