Metabolic effects of diclofenac on the aquatic food chain - 1 H-NMR study of water flea-zebrafish system.

In the environment, aquatic organisms are not only directly exposed to pollutants, but the effects can be exacerbated along the food chain. In this study, we investigated the effect of the food (water flea) on the secondary consumer (zebrafish) with the exposure diclofenac (DCF) Both organisms were exposed to an environmentally relevant concentrations (15 µg/L) of diclofenac for five days, and zebrafish were fed exposed and non-exposed water fleas, respectively. Metabolites of the water fleas were directly analyzed using HRMAS NMR, and for zebrafish, polar metabolite were extracted and analyzed using liquid NMR. Metabolic profiling was performed and statistically significant metabolites which affected by DCF exposure were identified. There were more than 20 metabolites with variable importance (VIP) score greater than 1.0 in comparisons in fish groups, and identified metabolites differed depending on the effect of exposure and the effect of food. Specifically, exposure to DCF significantly increased alanine and decreased NAD + in zebrafish, which means energy demand was increased. Additionally, the effects of exposed food decreased in guanosine, a neuroprotective metabolite, which explained that the neurometabolic pathway was perturbated by the feeding of exposed food. Our results which short-term exposed primary consumers to pollutants indirectly affected the metabolism of secondary consumers suggest that the long-term exposure further study remains to be investigated.