Although, silver nanoparticles (AgNPs) are used in many different products, little information is known about
their toxicity in tropical fish embryos. Therefore, this study evaluated the developmental toxicity of waterborne
silver nanoparticles in embryos of Clarias gariepinus. Embryos were treated with (0, 25, 50, 75 ng/L silver nanoparticles)
in water up to 144 h postfertilization stage (PFS). Results revealed various morphological malformations
including notochord curvature and edema. The mortality rate, malformations, and DNA fragmentation
in embryos exposed to silver nanoparticles increased in a dose- and embryonic stage-dependent manner.
The total antioxidant capacity and the activity of catalase in embryos exposed to 25 ng/L silver nanoparticles
were decreased significantly while the total antioxidant capacity and the activity of catalase were insignificantly
increased with increasing concentrations in the embryos from 24 to 144 h-PFS exposed to 50 and 75 ng/L silver
nanoparticles. Lipid peroxidation values showed fluctuations with doses of silver nanoparticles.
Histopathological lesions including severely distorted and wrinkled notochord were observed. The current data
propose that the toxicity of silver nanoparticles in C. gariepinus embryos is caused by oxidative stress and
genotoxicity.