Changes In Histological Features And Cholinesterase Activity In The Spleen Of African Catfish Clarias Gariepinus Upon Exposure To Cadmium
Cadmium (Cd) is widely dispersed into the environment through the air by mining and smelting as well as other man-made routes such as the usage of phosphate fertilizers, presence in sewage sludge, and also from various industrial applications. In this study, Clarias gariepinus (catfish) was used to elucidate the toxic effect of Cd on histology and cholinesterase (ChE) activity on the spleen of C. gariepinus after exposure for 96 hours at a different concentration of Cd. The results obtained demonstrate negative impacts at cellular level such the present of lymphocyte infiltration, increasing number of melanomacrophage center and necrotic area caused by Cd that led to alteration to the structure of tissues, which was observed to worsen with the increase in the concentration of Cd. At biomolecular level, spleen ChE from each untreated and treated sample were test in vivo and the result shown above 10 ppm concentration treatment of Cd statistically inhibit the enzyme activity (p<0.05). In vitro assay was conducted after the spleen ChE was purified using procainamide-based chromatography, and optimized based on pH (8.0 in 0.1 M Tris-HCl buffer), temperature (25-30oC) and substrate specificity (1.0mM of BTC). The half maximal inhibitory concentration (IC50) value for Cd was 4.788 mg/L. These findings suggested that the C. gariepinus spleen ChE is another candidate to be applied as a biomarker or biosensor in detecting the presence of heavy metals in the environment.
Index Terms - Cadmium; Clarias Gariepinus; Spleen; Histology; Cholinesterase