Assessment of anticholinesterase contaminants in selected sites of Ruvu river in Tanzania using cholinesterase biomarker in African Sharptooth Catfish (<i>Claria gariepinus</i>)

Abstract

Increase in human activities led to environmental contamination of physical, biological and chemical nature. Some of the contaminants can be determined using biomarkers such as Cholinesterases; Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) activities. A cross section study was performed to assess the anticholinesterase contaminants in Ruvu river using cholinesterase biomarker in African Sharptooth Catfish (Clarias gariepinus). A total of 40 fish was used to collectblood plasma and brain samples for AChE and BChE activities assessment. Ellman‘s methodand 5, 5‘-dithiobis-2-nitrobenzoic acid (DTNB) chromophore were used during enzymes activities determination. The findings of AChE and BChE activities in blood plasma and BChE activities in brain showed no statistical significant difference (p> 0.05) among the fish from the various study sites and between fish from the study sites and the control. Also, no statistical significant difference in the brain AChE was observed among the fish from the study sites. However (p˂ 0.05) was observed in fish from Ruvu Darajani when its AChE activities were compared with that of control fish. The percentage of AChE inhibited was higher in brain than in blood plasma whereas the inhibition of BChE activities was higher in blood plasma than in the brain of fish from Ruvu Darajani.Fish samples from Ruvu darajani were observed to have highest inhibitions for both the brain AChE and blood plasma BChE activities (31.7% and 13.4%respectively).This indicates that Ruvu Darajani is highly contaminated with anticholinesterase compounds than other areas. Therefore, this study revealed that activities of AChE and BChE in C. gariepinusare useful biomarker for assessing aquatic environmental contaminants caused by anticholinesterases.

Keywords: Anticholinesterases, Claria gariepinus, Biomarker, Ruvu river, Tanzania