Effect of nanosilver particles on metabolism and cortisol release in rainbow trout (Oncorhynchus mykiss)
Nanosilver (nAg) is a nanoparticle incorporated into products for its antimicrobial properties that causes diverse toxic effects. This study investigated the effects of nAg on metabolic rate and stress response in rainbow trout (Oncorhynchus mykiss Walbaum 1792). Fish were exposed to environmentally-relevant concentrations of nAg (average 0.28 μg l-1) and higher (average 47.60 μg l-1) for 28 days (d). Measurements of cortisol, growth, condition (K), and hepatosomatic index (HSI) were analyzed, as well as metabolic measurements. Cortisol concentrations were higher in all nAg exposures, and were significantly elevated in high exposures. No significant effects of nAg exposure were observed on metabolic variables, growth or condition. There was a significant effect of time and treatment on HSI, but no discernible trend. There was also a significant increase in cortisol in fish measured for metabolic variables. Overall nAg was seen to engage the stress response, but not affect metabolism or morphometric measures.