Asian Journal of Fisheries and Aquatic Research

The toxicity of tobacco (Nicotiana tobaccum) leaf dust with piscicidal and pesticidal properties was investigated on some enzymatic and protein synthesis activities of juvenile African mud catfish (Clarias gariepinus). Fish were exposed to both lethal and sub-lethal concentrations of tobacco leaf dust for 21 days in a renewal bioassay procedure. The median lethal concentrations (LC₅₀) were derived using Finney probit method while protein and enzymatic activities were determined using Biuret and Randox methods respectively. The LC₅₀ values for 48 hours acute bioassay test was 2.11g/l for tobacco leaf dust. Tobacco exposed fish showed significant increase (P≤0.05) in serum AST, ALT and ALP levels. Significant decrease (p≤0.05) were observed for liver AST (141.00 ± 2.52 to 154.67 ± 0.67), serum and liver total protein (6.47 ± 0.03 to 7.80 ± 0.40 and 3.30 ± 0.00 to 3.57 ±0.12)  and serum albumin (4.23 ± 0.09 to 4.83 ±0.20) across all concentrations. The study showed that exposure of C. gariepinus  juvenile to sub-lethal concentrations of tobacco (Nicotiana tobaccum) leaf dust can induce various toxicological effects in the form of enzymatic alteration. Therefore, the longer exposure of tobacco leaf dust in aquatic ecosystem is dangerous to fish and subsequently human health.