Immunotoxicity and oxidative damage in Litopenaeus vannamei induced by polyethylene microplastics and copper co-exposure.

This study examines the combined effects of polyethylene microplastics (PE-MP) and copper (Cu) on the immune and oxidative response of Litopenaeus vannamei. PE-MP adsorbed with Cu at 2.3, 6.8, and 16.8 ng (g shrimp)) were injected into L. vannamei. Over 14 days, survival rates were monitored, and immune and oxidative stress parameters were assessed. The results showed that combined exposure to PE-MP and Cu significantly reduced the survival rate and decreased total haemocyte count. Immune-related parameters (phagocytic rate, phenoloxidase and superoxide dismutase (SOD)) and antioxidant-related parameters (SOD, catalase and glutathione peroxidase mRNA and enzyme) also decreased, while respiratory burst activity significantly increased, indicating immune and antioxidant system disruption. Additionally, there was a significant increase in oxidative stress, as measured by malondialdehyde levels. Histopathological analysis revealed severe muscle, hepatopancreas, and gill damage. These results suggest that simultaneous exposure to PE-MP and Cu poses greater health risks to white shrimp.