A multiscale investigation of CdSe/ZnS-COOH quantum dots contaminated diet on Salmo trutta fario: potential food-related nanomaterial toxicity

Quantum dots (QDs) are widely investigated and exploited in industrial and biomedical domains, however, not well supported by appropriate toxicological studies and risk assessment. The present study tested the biological effects of CdSe/ZnS-COOH QDs-contaminated food after 7 days of oral exposure on Salmo trutta fario L juvenile at molecular, cellular, physiological and whole-organism levels. The CdSe/ZnS-COOH QDs-contaminated food after 7 days of oral exposure reduced the diversity and richness of the gut microbiota of Salmo trutta fry, but not significantly. On the other hand, LEfSe algorithm unveiled 28 significantly different taxa at different taxonomic levels between the control group and the QDs-exposed group. After 7 days of oral exposure to QD-contaminated food, the relative abundance of the genus Citrobacter (Proteobacteria phylum) significantly increased in the gut microbiota, while the relative abundance of the genus Mycoplasma (Tenericutes phylum) and the other genera: Acinetobacter, Chryseobacterium, Brevundimon, Exiguobacterium, Rhodococcus, Candidatus Amphibiichlamydia significantly decreased. It was also found that after 7 days of feeding fish with QDs-containing feed produces increasing somatic index of the liver, genotoxic effects in fish blood erythrocytes, enzyme activity and higher MDA level, and, also, significantly increases the levels of Cd accumulated in the gills and liver tissue. In summary, that QDs-contaminated diet affects the gut microbiota of fish by significantly changing the relative abundance of some taxa which may lead to dysbiosis and may pose a health risk to fish.