This study aims to determine, in a controlled environment, the impact of exposure to sub-lethal concentrations of the herbicide Atrazine on growth, feed utilization and energy budget in Clarias gariepinus. Fingerlings of C. gariepinus (2.54 ± 0.02 g mean weight, 7.32 ± 1.6 cm mean length) were exposed to concentrations of 0; 0.03165 and 0.3165 ppm Atrazine for 28 days. Biomass was assessed weekly and fish samples were taken from different aquaria to determine weight gain, specific growth rate, feed efficiency rate, protein efficiency ratio and the biochemical composition of fish. Results showed important behavioral reactions of the fish such as hyperexcitation, depth activity and surfacing activity during the first two weeks. Fish survival significanlty declined in exposed fish only during the first week. Atrazine inhibited the growth of C. gariepinus fingerlings throughout the exposure period without influencing feed utilization and protein efficiency compared with control fish. Carbohydrates were used primarily, followed by proteins and then lipids, as sources of energy in exposed fish, to meet energy demand generated by this chemical stressor.
Keywords: Clarias gariepinus, Chemical stressor, Growth parameters, Bioenergetic