Differences in the induction of cyp1A and related genes in cultured rainbow trout Oncorhynchus mykiss. Additional considerations for the use of EROD activity as a biomarker

Abstract

Two rainbow trout Oncorhynchus mykiss fish farms were repeatedly sampled in order to observe the variability of ethoxyresorufin-O-deethylase (EROD) activity and of related genes in the liver. Fish coming from fish farm A exhibited EROD levels that could be considered as basal according to the scientific literature, however, EROD activity in fish coming from fish farm B was significantly increased. This was accompanied by augmented aryl hydrocarbon receptor (ahr) and cytochrome P4501A (cyp1A) messenger RNA expression and reduced oestrogen receptor (er) and vitellogenin (vtg) transcription. Only sediment extracts from the entry channel of fish farm B induced EROD activity in O. mykiss cultured cells, however, this induction could not be explained by the levels of polyaromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) measured in the sediments. The results of this study point out that O. mykiss cultured in fish farms could be used as sentinels for indication of pollution. In this particular work, however, no conclusive evidence has been found for a relationship between the presence of PAHs and PCBs and the observed EROD induction.

Multi-biomarker responses as indication of contaminant effects in Gambusia affinis from impacted rivers by municipal effluents

“…In some previous studies, sex-related differences in P450 activity during the reproductive cycle have been reported in other fish (Andersson, 1990;Gray et al, 1991). Moreover, some previous studies showed a good correlation between EROD activity and CYP1A mRNA expression in fish (Quiró et al, 2007;Valdehita et al, 2012), but others also reported a poor correlation between EROD activity and CYP1A mRNA expression (Della Torre et al, 2010;Kammann et al, 2008;Karaca et al, 2014).…”

Liver biomarkers response of the neotropical fish Aequidens metae to environmental stressors associated with the oil industry

“…The procedure for the determination of EROD activity was selected according to multiple scientific literature supporting the effectiveness of the protocol (Lammel et al, 2015;Quesada-García et al, 2013, 2015Valdehita et al, 2012) and its reproducibility was standardized and validated in preliminary assays with different PAHs and flavonoids such as benzo[a]pyrene, pyrene and beta-naphthoflavone. EROD activity in liver of A. metae was determined in a S9 fraction according to the method described by Valdehita et al (2012) after standardization. Approximately 30 mg of liver was gently homogenized at 4 C in 1 mL of homogenization buffer (0-1 M Tris-HCl pH 7,0-25 mM sucrose, 150 mM KCl, 1 mM EDTA, 1 mM DTT, 0-25 mM PMSF and 20% glycerol).…”