Protective effect of dietary vitamin E on immunological and biochemical induction through silver nanoparticles (AgNPs) inclusion in diet and silver salt (AgNO) exposure on Zebrafish (Danio rerio).

The present study evaluated silver nanoparticle (AgNPs) toxicity using biomarkers of oxidative and metabolic stress, immunological impairment and cellular damage in zebrafish (Danio rerio), as well as the optimal dose of vitamin E neutralizing undesirable effects. Fish were fed for ten days and eight study groups were investigated: controls, AgNPs exposure alone (1.5 mg L) and combined with three different vitamin E doses (1.5 mg L of AgNPs + vitamin E 100, 200 or 400 mg kg of food), also one positive control group exposed to AgNO alone or combined with the same vitamin E doses. D. rerio exposed to AgNPs alone or combined with the lower vitamin E dose showed overall worse results in comparison with the control groups and the groups combining nanoparticles and 200 or 400 mg kg of food of vitamin E-supplemented diet. AgNPs caused cell impairment by increasing LDH activity and cortisol levels, generated oxidative stress by inhibiting SOD and CAT activity and immunosuppression by inhibiting ACH50 and lysozyme activity. The groups exposed to Ag salt showed the same response-pattern found for the NPs groups, reinforcing that Ag toxicity of AgNPs is mediated by Ag. In conclusion, although AgNPs are toxic to Danio rerio, vitamin E supplementation at 200 or 400 mg kg can act protectively against its toxic effects.