Microinjection of lipophilic extracts from feral baltic salmon (Salmo salar) roe predicted to develop M74 in yolk-sac fry of farmed salmon (Salmo salar) and brown trout (Salmo trutta)

The purpose of the study was to evaluate the hepatic 7-ethoxyresorufin O-deethylase (ERO D)-induction and whole fry immunohistochemical staining of cytochrome P4501A1 in two different salmonid species exposed by microinjection to the lipid soluble components extracted from feral Baltic salmon (Salmo salar) roe predicted to develop the larval mortality syndrome M74. In both salmon and brown trout (Salmo trutta), a dose-dependent induction of the hepatic EROD-activity was recorded. No dose-dependent induction was seen in groups exposed to different concentrations of the lipophilic substances extracted from farmed roe. The immunohistochemical study revealed an exposure-dependent induction of cytochrome P4501A1 in the liver and in endothelial tissue in both salmon and brown trout.