Acute toxicity and effects of titanium dioxide nanoparticles (TiO2 NPs) on some metabolic enzymes and hematological indices of the endangered Caspian trout juveniles (Salmo trutta caspius Kessler, 1877)

Titanium dioxide nanoparticles (TiO2 NPs) have been incorporated into a large range of materials for different usages and they are very likely to come in wastewater and sewage, finally reaching the aquatic ecosystems. Therefore, valuating the impact of TiO2 NPs on aquatic environment is a major concern. The aim of this work was to study the effects of TiO2 NPs on metabolic enzymes activity and haematological indices of the Caspian trout juveniles. After determining 96h-LC50, juveniles have been exposed to 0.1 LC50-96h TiO2 NPs in three replicates for 28 days. The blood samples were collected from fish after acute (24, 48, 72, 96 hours) and sub chronic (7, 14, 21 and 28 days) exposure to the TiO2 NPs. The analysis showed that the red blood cells count (RBC), haemoglobin (Hb), haematocrit (Hct), white blood cells count (WBC) and lymphocytes have been increased after acute and sub chronic exposure to TiO2 NPs. Levels of neutrophils and monocytes were increased mostly in acute treatments. Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC) showed no significant differences. According to analysis of metabolic enzymes activities, levels of Alkaline Phosphatase (ALP) and Aspartate Amino Transferase (AST) after acute and sub chronic exposure as compared to control group were increased/decreased, respectively. Alanine Aminotransferase (ALT) levels showed significant decrease (p<0.05) after 28 days. Lactate Dehydrogenase (LDH) enzyme level increased mostly after acute exposure. The obtained results indicated that the presence of very low amount of TiO2 NPs could affect most haematological and metabolic enzymes of Caspian trout juvenile.