Effect of reduced food intake on toxicokinetics of halogenated organic contaminants in herring gull (Larus argentatus) chicks

Abstract

Abstract-The aim of the present study was to investigate how contaminant exposure and reduced food intake affect tissue distribution and biotransformation of halogenated organic contaminants (HOCs) in Arctic seabirds using herring gull (Larus argentatus) as a model species. Herring gull chicks were exposed for 44 d to cod liver oil containing a typical mixture of contaminants. Following exposure, food intake was reduced for a one-week period in a subgroup of the chicks. Polyclorinated biphenyls, organochlorine pesticides, and brominated flame retardants, as well as a wide range of hydroxy, methyl sulfone, and methoxy compounds were measured in liver, brain, and plasma samples. Additionally, phase I biotransformation enzyme activities and phase I and II messenger ribonucleic acid (mRNA) expression were investigated in the liver, brain, or both. Both contaminant exposure and reduced food intake had an increasing effect on the concentrations of HOCs and their metabolites. The HOC exposure and reduced food intake also led to increased 7-ethoxyresorufin-O-deethylation (EROD) activity, whereas mRNA expression of the biotransformation enzymes increased only following the reduced food intake. Tissue distribution of HOCs and their metabolites was not affected by either contaminant exposure or reduced food intake. In conclusion, the results indicate that biotransformation capacity and formation of HOC metabolites increase during reduced food intake. This finding supports the hypothesis that reduced food intake increases the susceptibility of Arctic animals to the effects of lipophilic HOCs. Environ. Toxicol. Chem. 2013;32:156-164. # 2012 SETAC

Contaminants, prolactin and parental care in an Arctic seabird: Contrasted associations of perfluoroalkyl substances and organochlorine compounds with egg-turning behavior

“…whereas OCs are stored in adipose tissues before being released into the bloodstream during periods of accelerated lipid mobilization (Aas et al, 2014;Bustnes et al, 2010;Findlay and DeFreitas, 1971;Henriksen et al, 1995;Jones et al, 2003;Kelly et al, 2009;Luebker et al, 2002;Routti et al, 2013;Vanden Heuvel et al, 1992;Verreault et al, 2005). Consequently, we posit that PFASs and OCs could target physiological functions through very different modes of action, without mechanistic interlinkage, potentially resulting in mixed or contrasted responses.…”

Organochlorines, perfluoroalkyl substances, mercury, and egg incubation temperature in an Arctic seabird: Insights from data loggers

“…Previous research shows that birds (including kittiwakes), with high organochlorine burdens generally have poor body condition and are lighter in mass than birds with low organochlorine levels (Henriksen ; Henriksen et al , ; Helberg et al ; Bustnes et al ). When body mass decreases, the lipophilic organochlorines such as oxychlordane, previously stored in adipose tissues, are released into the blood circulation and become very toxic to the whole organism (Henriksen ; Borgå et al ; Nøst et al ; Routti et al ). It is thus difficult to disentangle a potential confounding effect of body mass or a real impact of contaminants on T inc .…”

Short-term fasts increase levels of halogenated flame retardants in tissues of a wild incubating bird

“…week, exhibited contaminant concentrations that were three times higher in liver, plasma, and brain compared to a non-fasted exposed group (Routti et al 2013). Changes in feeding rates and body mass throughout the breeding season have similarly been associated to contaminant concentrations in some seabirds, both those adapted to long fasts or not, including kittiwakes (Rissa trydactyla) (Henriksen et al 1996), and Adélie penguins (Pygoscelis adeliae) and southern fulmars (Fulmarus galacialoides) (van den Brink et al 1998).…”

“…In these situations, lipid mobilization during fasting can lead to increased circulating levels of contaminants as they are released from fat stores (Birnbaum 1985). Several studies have reported increased enzyme-mediated liver metabolism of contaminants following fasting, further confirming that increased organismal exposure occurs during these natural food deprivation phases (Helgason et al 2010;Jorgensen et al 1999;Routti et al 2013;Vijayan et al 2006).…”

“…In such species, even short-term or milder fasts have the potential to enhance lipid mobilization, which may as a result impact internal contaminant concentrations (e.g. Routti et al 2013). However, herring gull chicks (Larus argentatus) exposed to a mixture of environmental contaminants and subsequently fed a reduced (by 70%) but not fully restricted diet for one week, demonstrated a 10% loss in body lipids coupled with an increase in contaminants and their metabolites in liver, brain, and plasma (Routti et al 2013).…”