Influence of nutritional status on biomarker responses to PCB in the Arctic charr ( Salvelinus alpinus)

Transport of pollutants from industrial areas has resulted in Arctic environments facing increasing levels of organic pollution. Thus, a need for sensitive and reliable biomarkers that can be used to assess the risk associated with exposure to xenobiotics in these areas has arisen. In high latitudes, temporal variations in the nutritional status of animals can be considerable, and these variations may influence toxicokinetic processes and biomarker responses. In the present study, different biomarker (cytochrome P450 (CYP1A), pre- and post-stress plasma cortisol concentrations and fin erosion) responses were recorded in groups of PCB-exposed (given a single oral dosage of 1 μg Aroclor 1260 (g body weight) −1) and unexposed Arctic charr. Following treatment (PCB administration), fish were held for 141 days under either a restricted feeding regime or without food. PCB exposure did not effect either growth or organ lipid concentrations. Food deprivation resulted in a marked reduction in lipid concentration in muscle and kidney, and a 3- and 11-fold increase in the PCB concentrations in the kidney and liver of the PCB-exposed fish. Food deprivation did not appear to influence hepatic EROD activities and CYP1A content, but the elevated PCB concentration in the liver of the fasted, PCB-exposed fish seemed to result in a dose-related increase in EROD activity and CYP1A content. Plasma cortisol concentrations of unstressed fish were below the detection limit of 3.6 ng ml −1. Post-stress plasma cortisol concentrations were low in the food deprived fish, irrespective of PCB exposure. The highest post-stress plasma cortisol concentrations were recorded in PCB-exposed, fed fish. The fish that were held without food had the lowest incidence of fin erosion, whereas the combination of food deprivation and PCB exposure resulted in the highest prevalence of fin erosion. Thus, nutritional status (i.e. long term food deprivation) influenced both tissue concentrations of PCB, and biomarker responses. This must be borne in mind if biomarkers are to be used in environmental monitoring programmes.