Effect of acute and chronic toxicity of Cu nanoparticles on survival and histopathology of hepatopancreas and gills in Pacific white shrimp (Litopenaeus vannamei)

Identification of toxicity effects of nanomaterials in the field of aquatic nanotoxicology is of great significance. This study was conducted to evaluate the effect of acute and chronic toxicity of copper nanoparticles (CuNPs) on survival rate and histopathology of hepatopancreas and gills in PL5 of Pacific white shrimp (Litopenaeus vannamei). Acute toxicology test was done according to OECD no. 203 during 96 h and mortalities were recorded every 24 h after exposure of shrimps to concentrations of 0.1‚ 0.32, 1, 3.2, 10, 32 and 100 mg/lit of CuNPs with average size of 40 nm. Data of mortalities were analyzed by probit software. Median lethal concentration (LC50) was not determined because there was no special order in acute toxicity data. In fact, non dose-dependent mortalities of this species exposed to CuNPs inhibited the calculation of LC50. In chronic toxicity test, shrimps were exposed to concentrations of 0.1, 0.5 and 1 mg/lit of CuNPs for 21 days. Gill histology revealed many damages such as severe necrosis, shortening of the length of the secondary gill lamellae, severe increase of hemocytes and decrease of pillar cells compared to control. Histopathological effects in hepatopancreas of CuNPs exposed shrimps were enlargement of the cell nucleus, necrosis of some cells, as well as reduction of the number of functional cells and destruction of the tubules wall in compare to the control. In conclusion, exposure to CuNPs causes histopathological effects on hepatopancreas and gills of Pacific white shrimp which could finally result in the shrimp mortalities.