Biochemical and Histological Effects of Glyphosate on the Liver of Cyprinus carpio (Linn.)

Abstract

Glyphosate is an active ingredient of Roundup®, a herbicide which is extensively used for agricultural applications and control of vegetation in non-crop areas often leading to its runoff from sites of application into water bodies posing serious threat to non-target species including fish. The present investigation was undertaken to evaluate the biochemical and histopathological effects of glyphosate on the liver of freshwater fish, Cyprinus carpio (Linn.) after calculating the 96 h LC50 of glyphosate (Roundup®41% SL) which was 3.260 ppm. The fish fingerlings having mean wt. 3g ±0.5 and mean length 5.5cm ±0.35 were exposed to two sublethal concentrations of glyphosate i.e. 25% of LC50 (T1) and 50% of LC50 (T2) for a period of 28 days. Total soluble proteins, lipids and enzymatic activities of aspartate amino transferase (AST) and alanine amino transferase (ALT) were recorded at weekly intervals and significant (p>0.05) decrease in protein and lipid content of the liver was continually observed till the termination of the experiment. However, the enzymatic activities of AST and ALT in liver showed a significant (p<0.05) increase with increasing concentrations of glyphosate and duration of exposure. The histo-morphology of liver in fish exposed to glyphosate exhibited vacuolation of hepatocytes, pyknotic nuclei, degeneration of cytoplasm, and infiltration of leukocytes, necrosis and severe vasodilation in the treatments. The severity of biochemical and histological alterations was more pronounced in T2 after 28 days of exposure. The increase in activities of AST and ALT and the decrease in protein and lipid content of the liver following exposure of fish to the herbicide suggest enhanced protein catabolism, hepatocellular damage and increased utilization of energy stores to compensate for higher energy demands during stress. This indicates that the above said herbicide causes potential harm to the aquatic life.