Malachite Green Induced Hepatotoxicity in <i>Channa punctata</i> (Bloch, 1793)

Malachite green is an N-methylated diaminotriphenyl methane dye widely used in the silk, wool, jute and leather industries and has also been applied in aquaculture to control fungal, protozoan, and helminth infections. Despite its use, the dye has raised serious concerns due to its unethical use in food adulteration and its documented toxic and carcinogenic effects. In the present study, the toxic impact of malachite green on hepatic tissue and liver enzyme profiles in the freshwater fish Channa punctata was evaluated. At first, fish were exposed to different sub-lethal concentrations of malachite green for a period of seven days under controlled laboratory conditions. Results of biochemical analyses revealed a significant change in serum liver marker enzymes, including Alkaline Phosphatase (ALP), Serum Glutamic Pyruvic Transaminase (SGPT), and Serum Glutamic Oxaloacetic Transaminase (SGOT), in treated fish compared to the control group, which indicates hepatocellular damage and impaired liver function. Exposure to malachite green has also been shown to induce oxidative stress, which is evidenced by a statistically significant increase in antioxidant enzyme activities such as Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione-S-Transferase (GST). Histopathological examination of hepatic tissues further confirmed toxic injury, showing pronounced cellular degeneration, distorted cellular architecture, cytoplasmic vacuolation, and disruption of intercellular connective tissue. The study showed that sub-lethal exposure to malachite green causes marked biochemical, oxidative, and histopathological alterations in Channa punctata, clearly demonstrating its hepatotoxic potential. Histopathological studies of the lesions in the liver tissues revealed several morphological alterations, and mild to moderate severity of the lesions was observed. Major Findings: The findings highlight the ecological risk associated with the indiscriminate use of malachite green in aquaculture and emphasise the need for strict regulatory control to safeguard aquatic organisms and public health.