Trophic transfer of CeO nanoparticles from clamworm to juvenile turbot and related changes in fish flesh quality.

Engineered nanoparticles (ENPs) accumulate in marine sediments and exhibit adverse effects on benthic organisms. However, the effect of ENPs on marine benthic food chains is largely unknown. Herein, we investigated the trophic transfer and transformation of CeO ENPs within a simulated marine benthic food chain from clamworm () to turbot (), as well as their effects on fish flesh quality. The results showed that Ce contents in turbot increased with the accumulation of CeO ENPs in clamworm, but no biomagnification of CeO ENPs occurred along this food chain. During trophic transfer, CeO ENPs in turbot experienced transformation from Ce(IV) to Ce(III). Importantly, CeO ENPs accumulated in the muscle of turbot and decreased the crude protein, total amino acid, and delicious amino acid contents, as well as the texture of the muscle. CeO ENPs induced the deterioration of flesh quality, which was mainly related to metabolism in muscle and intestinal disorders caused by oxidative stress. Specifically, CeO ENPs increased the relative abundance of and in the turbot intestine while decreasing those of , , and . Significant disturbances in purine and amino acid (aspartate, glutamate, glycine, etc.) metabolism in muscle were induced by CeO ENPs. Moreover, correlation analysis showed that microbiota dysbiosis was highly correlated with muscle metabolic dysfunction. Our study provides insights into the transfer and transformation of CeO ENPs and their interference with fish flesh quality via the gut-muscle axis, providing useful information on assessing ecological risk and food safety in marine environments.