Oxidative effects of consuming microplastics in different tissues of white shrimp Litopenaeus vannamei

Pathological and biochemical effects of polyethylene microplastic exposure in hydrothermal vent crab, Xenograpsus testudinatus

Microplastic pollution significantly threatens marine ecosystems, including those with unique adaptations. This study evaluates the implications of polyethylene microplastics (PE-MPs) on the hydrothermal vent crab, Xenograpsus testudinatus. Crabs were exposed to varying fluorescent green polyethylene microspheres (FGPE) concentrations for 7 days. Histological analysis revealed severe damage to the hepatopancreas and gills at higher FGPE concentrations. Antioxidant enzyme activities (SOD, CAT, GR, GST, GPx, LPO) and gene expression (sod, cat) were assessed to evaluate oxidative stress responses. Results indicated significant upregulation of SOD and CAT activities at lower FGPE concentrations, suggesting an initial antioxidant response. However, GR and GST activities were inhibited at higher concentrations, and oxidative stress markers increased. These findings proved that PE-MPs induce molecular oxidative damage and lead to possible oxidative responses. Despite their resilience to extreme environments, HV crabs are vulnerable to pollutant-induced stressors, which pose ecological risks to species interactions and population dynamics within vent ecosystems.

Bioaccumulation and biochemical impact of polyethylene terephthalate microplastics in Cipangopaludina chinensis: Tissue-specific analysis and homeostasis disruption

Microplastics are a novel pollutant that adversely affect freshwater benthic organisms. However, few studies have investigated the mechanism underlying the bioaccumulation and the toxicity of microplastics. In this study, microplastics bioaccumulation of wild Cipangopaludina chinensis in the Songhua River were utilized, and a 28-day aquatic toxicity test was performed to determine the effects of exposure to polyethylene terephthalate (PET), the bioaccumulation of PET, and changes in multiple biomarkers in the muscle, gill, and kidney tissues. The concentration pattern of microplastics was as follows: kidney tissue > muscle tissue > gill tissue. Microplastic ingestion caused AChE inhibition led to significant increases in redox and energy metabolism indicators. Furthermore, the IBR analysis presented a "response-resistance-breakdown" process, indicating that Cipangopaludina chinensis possessed resistance with time (D14 and D21) and concentration (0.10 mg/L and 1.00 mg/L) thresholds. Tissue sensitivity to microplastics was ranked as gill > muscle > kidney, which was the opposite order of microplastic accumulation. These findings implied that less sensitive tissues stored a larger amount of pollutants, suggesting a reduction in tissue sensitivity to microplastics with higher microplastic occurrence rates. This study provides new insights into biological resistance to pollutant stress, warranting further investigation into the underlying mechanisms.

Microplastic pollution in aquafeed of diverse aquaculture animals

Microplastics have emerged as pervasive contaminants, and determining their occurrence in aquafeed is key for evaluating their risks to farmed animals and, by extension, humans. However, knowledge about microplastic in aquafeed is still limited. Herein, we determined microplastic characteristics in aquafeed for five important aquaculture animals with different feeding habits. Aquafeed samples were collected for spotted sea bass, shrimp, grass carp, Tilapia, and frogs from main companies in China. The samples were digested using chemical digestion, and the residuals were subjected to a density separation. Microplastics were identified under the microscope and characterized by their shape, color, size, and polymer type. The results showed that microplastics are highly abundant in the feed of frogs, followed by spotted sea bass, Tilapia, grass carp, and shrimp. We found that feed size contributes to the total microplastic abundance in the feed. Further, microplastics were mainly in microfiber form, and the dominant polymer type was propylene, suggesting that packaging and processing are the main sources of pollution. Additionally, the most abundant size of microplastics was 100-1000 μm. Calculating microplastic ingestion risk, the spotted sea bass had the greatest recorded risk of microplastic ingestion, followed by grass carp, frogs, Tilapia, and shrimp. This study lays a foundational step toward understanding microplastic effects on aquaculture animals and calls for further environmentally relevant laboratory experiments to assess the risk of microplastic ingestion on animals and potential transfer to humans.

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 (Cu2+) on the immune and oxidative response of Litopenaeus vannamei. PE-MP adsorbed with Cu2+ at 2.3, 6.8, and 16.8 ng (g shrimp)-1) 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 Cu2+ 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 Cu2+ poses greater health risks to white shrimp.

The occurrence of pollutants in organisms and water of inland mariculture systems: Shrimp aquaculture is a procession of Microplastics accumulation

Microplastics (MPs) pollution in the ocean was widely concerned, but the current study on MPs pollution in the mariculture system is relatively lacking. This study researched the MPs pollution characteristics in water and shrimp at different stages of the pond and industrial aquaculture. The study shows that in the same aquaculture stage, MPs abundance in shrimp and water in pond aquaculture mode is higher than that in industrial aquaculture mode. The MPs pollution characteristics in shrimp and water show significant consistency. The hazard index of MPs in pond water and industrial models are 122 (Level Ⅲ) and 540 (Level Ⅲ), respectively, indicating that industrial aquaculture models may suffer from more severe MPs stress. The aquaculture period and mode significantly affected the MPs abundance of water and shrimp, but there was no interaction between the aquaculture period and mode. MPs abundance in shrimp show a significant relationship with the length of crustacean and weight. This study further enhanced the understanding of MPs pollution of water and organisms in different aquaculture modes at different stages, and warned MPs is widely spread in mariculture systems.