Toxicity of Tobacco (Nicotiana tobaccum) Leaf Dust on Enzymatic and Protein Synthesis Activities of African Mud Catfish (Clarias gariepinus)

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.

Assessment of toxic potential of three different heavy metals to Clarias batrachus (Linn.) utilizing static acute bioassay

Acute toxicity bioassay of three different heavy metals copper (Cu), lead (Pb) and cadmium (Cd) for the freshwater catfish, Clarias batrachus were conducted for evaluation of the toxicity. The 96h LC50 values recorded for Cu, Pb and Cd were 15 ppm, 29 ppm and 35 ppm respectively. The results of this study indicate that the order of toxicity of these heavy metals is Cu>Pb>Cd in short duration acute toxicity experiments. The toxicity was found to be dependent on dose and duration of experiment for all these heavy metals. Cu was found to be much more toxic than Pb and Cd to C. batrachus.

Histopathologic changes in the kidney tissue of Prochilodus lineatus Valenciennes, 1836 (Characiformes, Prochilodontidae) induced by sublethal concentration of Trichlorfon exposure

Studies were carried out to analyse the kidney histopathological alterations of "curimbatá", Prochilodus lineatus, were analyzed. An acute bioassay was made by the water contamination with 0.2muml/l of Dipterex 500 (Trichlorfon). The kidney tissue collected after 24 hours of exposure showed an enlargement of intercapsular space with glomerular atrophy, hypertrophy of the kidney tube cells, with small granules on its cytoplasm and little nuclear alteration. Blood overflowing from capillaries with pyknotic nuclei and vacuoles in the cytoplasm it was also noticed. After 48 hours, the kidney tissue showed glomerular expansion, impossibility to visualize the intercapsular space as well as cytoplasm limit of many cells. The parietal capsular epithelium and the basal membrane presented loss of cell content, the tubular cells appeared swollen vacuolated and with thin and thick cytoplasmatic granulations. Some of the cell nuclei kept relatively regular form with a condensed chromatin on its central region, while others showed themselves relatively small and pyknotics advancing to a cariolisis and necrosis focus.