Effect of sub-acute copper oxide nano-particles on gill tissue and some haematological indices of Caspian Roach (Rutilus rutilus caspicus)

There is a rising concern about the potential risks of nanomaterials to human health, the environment, and aquatic ecosystems. The chemical composition and small size of the nanomaterials are the most important factors in the toxicity of these materials. Histological study of gill and investigation of hematological parameters are important for monitoring the health condition in aquatic animals. Therefore, the effects of subacute concentrations of copper oxide nanoparticles were examined on some hematological parameters of Caspian Roach (Rutilus rutilus) in this study. The experiment was performed at 15 liters aquariums in three experimental groups including 10, 40, 80 ppm copper oxide nanoparticles and the control group for 42 days. Each treatment included three replicates consisting of seven juvenile carp with an approximate weight of 42± 2 gr. The results of this experiment showed that copper oxide nanoparticles caused hyperplasia, lamellar fusion, epithelial hypertrophy, lamellar aneurism, and reduce secondary lamellae length. Besides, red blood cells (RBC) was significantly decreased with the increase in the concentration of copper oxide nanoparticle (P<0.05). RBC had a significant reduction from 2.11±0.004 to 1.98±0.005 at the end of treatment. Hematocrit and hemoglobin reduced from 1.37±0.011 to 1.34±0.001 and 7.8±0.01 to 6.9±1.32, respectively (P<0.05). A significant reduction was recorded in hematocrit among the control groups and other treatments (P<0.05). it can be concluded that the sub-acute particles may cause damage to the surface of tissues, especially gill tissue, and changes in the level of blood factors in fish, which can be due to the destructive effects of nanoparticle type on hematopoietic organs such as the liver and kidney. Therefore, a definite conclusion requires more and more extensive research on the same species and other species.