Effects of some pesticides on histopathological and biochemical aspects of Euphlyctis hexadactylus (Lesson)(Amphibia: Anura)

Abstract

In the present study effects of two commonly used pesticides, nuvacron and carbaryl, on the histopathological and biochemical aspects of the green frog Euphlyctis hexadactylus were investigated. Experiments were conducted using standard toxicological methods. Test animals were exposed to sublethal and median lethal concentrations of the pesticides for thirty days. Histopathological alterations in liver, kidney and gonads and changes in the biochemical parameters such as glucose, glycogen, protein, lipid, cholesterol, and the enzymes _ acid phosphatase and alkaline phosphatase _ in the tissues such as blood, liver and muscle were studied. The results obtained clearly revealed that effects were concentration and time dependent and both the pesticides are toxic to the frog. No major difference in toxicity between nuvacron and carbaryl was found. Histopathological studies revealed severe damage in the tissue architecture of liver, kidney and gonads of exposed frogs. In biochemical studies various energy resources like glycogen, protein and lipid depleted in a progressive manner and there was an increase in cholesterol and acid phosphatase. Glucose and alkaline phosphatase recorded an initial increase but later a decline. These results indicate an initial attempt or the physiological adaptability of the frog to the stress induced by nuvacron and carbaryl. But later decline in glucose, protein, total lipid, and alkaline phosphatase in different tissues along with a severe damage in the tissue architecture of the organs like liver, kidney, testes and ovaries indicate the failure of these defending mechanisms. The profound damages in the testes and ovaries of treated frogs adversely affect male and female fertility causing deleterious effects on the reproductive potential of the animal and in the long run this may even affect the population size of Euphlyctis hexadactylus. The investigation emphasizes the need for the judicious use of pesticides.