Histopathological effects of tobacco leaf extract on juvenile African catfish muscle

Abstract

In Subsahara Africa, most indigenous small and medium scale catfish farmers have relied on the effectiveness of tobacco leave (Nicotiana tobacum) to treat ponds before stocking. Nicotiana tobacum in solution eliminates microbes and toxins which can be harmful to fish health. As a follow up, it is necessary to investigate if a left over minute concentration, has adverse effect on aquatic health. For this reason, the effect of ethanol extracts of Nicotiana tobacum leaf on the histopathology of muscles of juvenile fresh water Clarias gariepinus (African catfish) was investigated. The fish were acclimated for 14 days. Sublethal concentrations (0.25 mg/l, 0.50 mg/l, 0.75 mg/l, 1.00 mg/l and 1.25 mg/l) of ethanol leaf extract of Nicotiana tobacum in aqueous media were prepared. Each aquarium had 10 juveniles of mean length 6.9 ± 0.62 cm. After initial acclimation, the fish was exposed to the media for 96 hours. Histopathological micrograph of the catfish muscle tissue exposed to sublethal concentrations of Nicotiana tobacum indicate breakage of myofibrils, disintegrated myotomes, bunding of myotomes, lesions, hemorrhage and tissue inflammation. Preliminary Scanning electron microscopy of the ethanol extract of Nicotiana tobacum leaves showed the micro surface structure (morphology) and elemental composition of the extract. Results obtained from this work indicate that Nicotiana tobacum used as a biological control to eradicating predators and unwanted organisms in the ponds by local farmers in place of agrochemicals, if not controlled can exact varying degree of negative histopathological effect on the muscles of juvenile African cat fish, Clarias gariepinus.