Study on histo-biochemical biomarkers of chromium induced toxicity in Labeorohita

Abstract

Aquatic environment gets highly polluted due to the presence of heavy metals, which are usually discharged into water bodies because of rapid industrialization. The main purpose of this study is to evaluate the effects of chromium toxicity on histo-biochemical biomarkers of Labeo rohita. A total of 240 randomly selected fish were distributed into four aquaria (n = 20). Three groups designated as T1, T2 and T3 were exposed with 1/3rd, 1/5th and 1/10th of LC50 of chromium chloride, and the fourth group was chromium-free control (T0). Results showed a significant (p < 0.05) decrease in blood parameters such as hematocrit, red blood cells, hemoglobin, mean cell hemoglobin and platelets. In contrast, mean cell volume and white blood cell values increased significantly. The results obtained by comet assay showed that DNA damage was increased significantly (p < 0.05) in chromium-exposed groups compared to the control. At the histopathological level, observed alterations in the gill tissues are degeneration of epithelium, fusion of secondary lamellae, lamellar curling, hypertrophy, telangiectasis and oedema, while in the liver is necrosis, dilation of the vein, congestion of blood vessels, hepatocytes degeneration, melano-macrophage centers, pigmentation and hemorrhage. In the kidney, histological alterations such as glomerular destruction, necrosis, damaged blood vessels, oedema and pigmentation were seen. Those results suggest that chromium has the ability to bring variations DNA integrity, histopathology and blood of Labeo rohita.