Effects of long-term dietary exposure to organohalogen contaminants on vitamin and hormonestatus in the Greenland Sledge dog ( Canis familiaris )
The known overall dynamics of vitamin and endocrine disruption from organohalogen contaminants (OHCs) continue to be challenged by the constant change in complex mixtures of environmental chemical pollutants, as human desire to innovate continue. There is a great need for understanding threshold lev...
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| Format: | Book |
| Language: | English |
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National Environmental Research Institute, Aarhus University, Department of Arctic Environment and Faulty of Health Sciences, University of Southern Denmark
2009
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| Online Access: | https://pure.au.dk/portal/da/publications/effects-of-longterm-dietary-exposure-to-organohalogen-contaminants-on-vitamin-and-hormonestatus-in-the-greenland-sledge-dog-canis-familiaris(e4a73c50-dc16-11de-9e3b-000ea68e967b).html http://www.dmu.dk/pub/PHD_MKI.pdf |
| Summary: | The known overall dynamics of vitamin and endocrine disruption from organohalogen contaminants (OHCs) continue to be challenged by the constant change in complex mixtures of environmental chemical pollutants, as human desire to innovate continue. There is a great need for understanding threshold levels for each contaminant and its metabolites, but even more so the multifaceted toxicity of the complex mixtures of OHCs affecting the different animals and their organ systems. In order to mimic a long-term OHC mixture exposure situation, this study was performed as an exposure-control feeding study conducted on Greenland sledge dogs. This aimed at exploring how a diet rich in OHCs affects vitamin and hormone status in Arctic top predator mammals. The dogs were supplemented with fat containing high (exposed group: minke whale blubber) or low (control group: porcine fat) amounts of OHCs, polyunsaturated lipids and vitamins. The study showed negative correlations between e.g. vitamin A and DDT and PBDE. Also liver vitamin D (25OHD3) in exposed females was signifi cantly lower, although they had received approximately 33% more vitamin D3 than controls. Despite the limited sample size, also testicular weights in male offspring were signifi cantly lower in the exposed group, while plasma testosterone concentrations (and other male parameters) showed no signifi cant difference between groups. The exposed females had signifi cantly lower concentrations of thyroid hormone (Free T4) across all observations (6 to 18 months of age), and also for Free and Total T3 and T4, when sampled between 10 to 18 months of age. The present thesis supports the notion that wild mammals at the top of Arctic food chains are suffering from chronic non-lethal, subclinical symptoms due to exposure to complex environmental organohalogen contaminant mixtures. |
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