Impact of teflubenzuron on the rockpool shrimp (Palaemon elegans)

Concerns have been raised over the environmental impacts of antiparasitic drugs used to delouse farmed salmon. Released into the marine environment, some of these drugs can have negative impact on non-targeted crustaceans in the vicinity of farming facilities. In this study, we examined the molecular effect of the insecticide teflubenzuron on a shrimp species inhabiting the littoral zone, the rockpool shrimp (Palaemon elegans). Rockpool shrimp was exposed for 98 days to a dose representing 2% of a regular teflubenzuron medication applied to Atlantic salmon. Accumulation of teflubenzuron was studied in whole body samples, except abdominal segments 5 and 6, which were used for gene expression analysis. Insight into sublethal mode of action was sought by examining the transcriptional responses of 38 genes encoding proteins linked to molting and exoskeleton change, stress and detoxification. The accumulated levels of teflubenzuron in exposed animals varied between 1.7 and 33.0 ng/g. Significant transcriptional effects of exposure were seen for markers linked to molting and exoskeleton change (chh, ctbs, gap65), stress and apoptosis (hsp40, hsp70, casp3), as well for detoxification (cyp6a18). In conclusion, this study shows that teflubenzuron can bioaccumulate in shrimps living in the littoral zone and at sublethal concentrations affects molecular mechanisms in non-hepatopancreatic tissue.