Evaluation of chromium toxicity on hepatic health of Labeo rohita under controlled laboratory conditions

The current study aimed to assess the impact of chromium toxicity on hepatic biomarkers and oxidative stress in Labeo rohita (L. rohita) under controlled laboratory conditions. A total of 240 acclimated fish were randomly allocated to four treatment groups, each consisting of three replicates. The treatment groups T1, T2, and T3 were exposed to 1/10th, 1/5th, and 1/3rd of the 96-hour LC₅₀ concentration of chromium, respectively, while fourth group served as the control without chromium exposure. The experiment was conducted at a constant water temperature (30 ± 1 °C) and pH (7.5). Fish samples were collected on the 7th, 14th, and 28th days post-exposure for biochemical analysis of liver enzymes like alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) along with albumin, globulin, total protein and lipid peroxidation (LPO) levels. The results showed a significant (p ≤ 0.05) increase in hepatic enzyme (ALP, ALT and AST) activities, antioxidant enzymes (SOD, CAT) and LPO levels with increasing chromium concentrations and exposure duration, indicating progressive hepatic damage and oxidative stress. Conversely, total protein, albumin, and globulin concentrations showed a marked decline across all treated groups compared to the control, with the lowest values observed in fish exposed to the 1/3rd LC₅₀ concentration on the 28th day. These findings suggest that chromium exposure exerts dose- and time-dependent hepatotoxic effects in L. rohita, leading to impaired liver function and enhanced lipid peroxidation. The study provides valuable baseline information for understanding chromium-induced biochemical alterations in freshwater fish species and can contribute to environmental risk assessment and aquatic health management.