Organohalogens in A Whale-Blubber-Supplemented Diet Affects Hepatic Retinol and Renal Tocopherol Concentrations in Greenland Sled Dogs (Canis familiaris)

Abstract

The aim of this study was to examine the plasma, liver, and kidney status of vitamin A (retinol) and vitamin E (α-tocopherol) in two groups of Greenland sled dogs (Canis familiaris), with a total number of 16 bitches and 8 pups. The dogs were fed either minke whale (Balaenoptera acuterostrata) blubber (exposed dogs) or uncontaminated (control group) porcine fat for up to 12 to 21 mo of age. The daily intake of 50–200 g whale blubber (mean: 112 g) constituted between 10.4 and 11.7 µg/kg body weight ∑organohalogen contaminants (OHC) (or between 4.6 and 6.1 µg/kg body weight ∑polychlorinated biphenyls [PCB]). Retinol was approximately 18% and α-tocopherol 22% higher in the diet of the exposed dogs compared to controls. In adipose tissue, mean of ΣOHC was 92 ng/g lipid weight (lw) and 5005 ng/g lw for all control (n = 12) and exposed dogs (n = 10), respectively. Hepatic retinol correlated negatively with Σ-dichlorodiphenyldichloroethane (ΣDDT) and and Σ‐polybrominated diphenyl ethers (ΣPBDE) for all exposed animals. A negative correlation between kidney α‐tocopherol and ΣPCB concentrations was observed, whereas two positive significant correlations were observed between kidney retinol and Σ-chlordane-related compounds (ΣCHL) and dieldrin concentrations. Hepatic α-tocopherol concentrations were significantly lower in exposed compared to controls, most likely due to a combination by OHC exposure and high dietary intake of unsaturated fatty acids. These results suggest that dietary exposure from OHC may, even at low concentrations, possibly affect retinol and α-tocopherol status in Arctic top predators.

The Danish Cooperation for Environment in the Arctic, Natural Science and Engineering Research Council (NSERC) Canada, Royal Canin, Kruuse Aps Lundbeck, and EU Marie Curie Fellowship are acknowledged for financial support. T. D. Rasmussen, M. J. Rasmussen, and S. Shahmiri (NWRC/CWS, Environment Canada) are thanked for caring for the sled dogs and chemical analyses of the sled dog tissues, respectively, and Philippe Grandjean and A. L. Jensen for valuable comments.