Growth and metabolism of Clarias gariepinus (Burchell, 1822) fed with copepods (Eucyclops sp.) exposed to lead and titanium dioxide nanoparticles

Abstract

The increasing uses of lead (Pb2+) and titanium dioxide nanoparticles (nTiO2) in commercial products have led totheir increased discharge into aquatic environments. This study investigated the effects of the interaction betweennTiO2 and lead (Pb2+) in a simple freshwater food web model consisting of zooplankton (Eucyclops sp.) and theAfrican catfish Clarias gariepinus. The growth performance and nutrient composition of Clarias gariepinus fedwith contaminated zooplankton alone and combined mixtures of nTiO2 (0.20 μM) and Pb2+ (0.01 and 0.04 μM),respectively, were evaluated after a chronic (28 days) semi-static laboratory bioassay. Our results demonstrateda decrease in the bioaccumulation of Pb2+ in fish exposed to the binary mixtures. The interaction of the mixturescaused significant (p < 0.05) retardation of growth of the fish through decreases of specific growth rate andallometric growth. Furthermore, a significant (p < 0.05) decrease of nutrient composition in fish tissues (muscles)was elicited in protein (20.66 to 16.73%), ash (5.96 to 5.69 %), moisture (16.2 to 14.8 %) and total lipid (10.04 to6.62%). The findings of this study suggest that feeding fish with copepods contaminated with Pb2+ and nTiO2mixtures could negatively affect the growth and nutrient composition (protein, ash, moisture and total lipid) offreshwater fish species, such as C. gariepinus.