Comparison of the dietary bioavailability of copper sulphate and copper oxide nanomaterials inex vivogut sacs of rainbow trout: effects of low pH and amino acids in the lumen

Abstract

Diet is an important exposure pathway of engineered nanomaterials (ENMs) in fish, but the long duration of in vivo toxicity tests is a barrier to hazard assessment.

Dietary exposure to copper sulphate compared to a copper oxide nanomaterial in rainbow trout: bioaccumulation with minimal physiological effects

“…This was likely caused by increased dissolution of the CuO ENMs in the gut lumen in the presence of cysteine, and transport of Cu-cysteine into the tissue via dissolved Cu uptake pathways. 19 Together, these data supported the hypothesis that intact nanoscale particulates of Cu are too large for uptake on solute transporters [see discussion Handy et al;20 as demonstrated for silver (Ag) ENMs 21 ], but also demonstrate that the chemical composition of gut lumen can drive the transformations of metallic ENMs and subsequent total Cu uptake. 19 Notably, the bioaccumulation potential of the CuSO 4 and CuO ENMs in fish has been shown using the ex vivo gut sac technique.…”

“…19 Together, these data supported the hypothesis that intact nanoscale particulates of Cu are too large for uptake on solute transporters [see discussion Handy et al;20 as demonstrated for silver (Ag) ENMs 21 ], but also demonstrate that the chemical composition of gut lumen can drive the transformations of metallic ENMs and subsequent total Cu uptake. 19 Notably, the bioaccumulation potential of the CuSO 4 and CuO ENMs in fish has been shown using the ex vivo gut sac technique. 19 In as little as 4 hours, total Cu from both materials accumulated in the mucosa of the gastrointestinal tract of rainbow trout, with the highest concentrations in the mid and hind intestines.…”

“…Recently, we demonstrated negligible tissue accumulation of total Cu from CuO ENMs using an ex vivo gut sac technique in rainbow trout with a simple physiological saline; CuO ENMs were associated with the mucosa, and unlike dissolved Cu, did not transfer to the blood compartment. 19 While CuO ENMs were dispersed in the simple physiological saline, the lack of uptake was unexpected, and further experiments in the same study explored the addition of amino acids that would be present in the chime in vivo. By adding the amino acid, cysteine, Cu was shown to accumulate in the blood compartment of the gut sacs.…”

“…19 Notably, the bioaccumulation potential of the CuSO 4 and CuO ENMs in fish has been shown using the ex vivo gut sac technique. 19 In as little as 4 hours, total Cu from both materials accumulated in the mucosa of the gastrointestinal tract of rainbow trout, with the highest concentrations in the mid and hind intestines. 19 To investigate this further, the present study explored the bioaccumulation of CuSO 4 and CuO ENMs in juvenile rainbow trout exposed via the diet for 28 days.…”

Trophic transfer of CuO NPs from sediment to worms (Tubifex tubifex) to fish (Gasterosteus aculeatus): a comparative study of dissolved Cu and NPs enriched with a stable isotope tracer (65Cu)

“…There are only a few studies assessing dietary uptake of nanoparticulate Cu in fish, and findings concerning the intestinal absorption efficiency and accumulation in inner tissues compared to dissolved Cu species vary. [34][35][36] Some information on NP transfer from invertebrate prey organisms to fish can be inferred from studies that examined intestinal uptake and accumulation of metalIJoxide) NPs from spiked artificial diets. [37][38][39][40][41][42][43][44][45] Altogether, the data from the few studies published on dietary exposure of fish to Cu(O) NPs suggest that Cu from NP-spiked diet is available, but uptake is limited compared to dissolved Cu.…”