Sublethal Effects of Tobacco (Nicotiana Tobaccum) Leaf Dust on Enzymatic Activities of Heteroclarias (a Hybrid of Heterobranchus Bidorsalis and Clarias Gariepinus)

Tobacco (nicotiana tobaccum) leaf dust has both piscicidal and fertilizer properties. thus there is a need to study its effects at sub-lethal concentrations (375.60, 187.80, 93.90 0.0mg/l) on some enzymatic activities of heteroclarias in a static semirenewable bioassay system with the aim to ascertain its effect on the test fish after the 14 days exposure period. water quality parameters and physiological parameters were monitored/determined according to standard procedures. water quality parameters were monitored after 48hours with the exception of temperature which was monitored daily. the monitored water quality parameters such as temperature, free carbon (iv) oxide, ph and dissolved oxygen were significantly decreased while total alkalinity and conductivity increased significantly in the exposed media, compared to the control test. the effects of the plant dust on the test fish was dose-dependent, revealing insignificant difference in alkaline and acid phosphatases, aspartate and alanine aminotransferases and gamma glutamyltransferase while significant difference was observed in lactate dehydrogenase in serum, liver and kidney respectively of the fish exposed to the plant dust, compared to the control after the 14 days exposure period. from the determined enzymatic activities, the effect of the plant dust was most pronounced in the kidney, but less in the liver and in the serum. however, the monitored water quality parameters revealed that the plant dust has effects on primary productivity, and consequently the biodiversity of organisms