Effect of feeding of cyclopoid copepods (Eucyclop sp.) exposed to engineered titanium dioxide nanoparticles (nTiO2) and Lead (Pb2+) on Clarias gariepinus growth and metabolism

Abstract

Abstract Background The application of Lead (Pb2+) and titanium dioxide nanoparticles (nTiO2) in commercial products is on the rise since the development of nanotechnology. The increasing usage of products containing these compounds had led to the rise of their concentration in aquatic environment, but information on the potential risk of co-exposure of these compounds in aquatic environment is still limited. In this study, the effect of feeding Clarias gariepinus with cyclopoid copepods exposed to engineered Pb2+ and nTiO2 on growth performance, and proximate composition of Clarias gariepinus was investigated. Methodology A chronic (28 days) laboratory bioassay was carried out by feeding C. gariepinus fries with cyclopoid copepods exposed to nTiO2 (7.5, 16.5 μg L−1) and Pb2+ (6.5, 15 μg L−1) alone as well as binary mixtures through dietary uptake. Results Our results indicate negative allometric growth (b < 3), while the highest condition factor (1.74) was recorded in the control. A significant decreased of specific growth rate (SGR) compared to the control was observed in exposed fish. Some parameters of proximate composition (crude protein, ash, moisture, total lipid) from the fish decreased significantly (P < 0.05) with synergistic effect on binary mixture. In contrast, carbohydrate content increased significantly (P < 0.05) with synergistic effect on binary mixture. Conclusion The present study clearly indicates that the chronic exposure of nTiO2 and Pb2+ mixtures caused the delay in the growth performance and changes in the proximate compositions of the fish. This findings raise concern regarding the fate of higher trophic level feeding on primary consumers inhabiting freshwater ecosystems contaminated with nTiO2 and Pb2+.

Keywords

• Heavy metal
• Nanomaterials
• Binary mixture
• Biochemical composition
• Stress