Individual and mixture effects of Nano-TiO2 and microplastics on antioxidant and immunological responses of Nile tilapia juvenile, Oreochromis niloticus (L.)

This study aims to evaluate the effect of nano titanium dioxide and microplastics, alone and in combination, on immune system function and oxidative stress of juvenile Nile tilapia, Oreochromis niloticus.For this purpose, fish were randomly divided into 27 100L tanks using a 3×3 factorial design, including three concentrations of Nano titanium dioxide (0, 1, and 5 mg/l) and three concentrations of microplastic (0, 0.5, and 1 mg/l) separately and together each in triplicate. The results showed that immunoglobulin, malondialdehyde(MDA), and glutathione reductase (GR) had significant effects in all groups (P<0.05). Lysozyme, total antioxidant capacity (TAC), and glutathione peroxidase (GPx) showed significant differences between the combined groups and the control (P<0.05). No significant differences were observed in C3 and C4 between groups exposed to MPs and Nano-TiO2 and the control (P>0.05). Superoxide dismutase (SOD) showed significant differences between the group exposed to MPs and Nano-TiO2 alone and the control group (P<0.05). In conclusion, the results showed that MPs could have a synergistic effect on the toxicity of Nano-TiO2.