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

The aim of this study was to examine the plasma, liver, and kidney status of vitamin A (retinol) and vitamin E (-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 mu g/kg body weight Sigma organohalogen contaminants (OHC) (or between 4.6 and 6.1 mu g/kg body weight Sigma polychlorinated biphenyls [PCB]). Retinol was approximately 18% and -tocopherol 22% higher in the diet of the exposed dogs compared to controls. In adipose tissue, mean of sigma OHC 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 sigma-dichlorodiphenyldichloroethane (sigma DDT) and and sigma-polybrominated diphenyl ethers (sigma PBDE) for all exposed animals. A negative correlation between kidney -tocopherol and sigma PCB concentrations was observed, whereas two positive significant correlations were observed between kidney retinol and sigma-chlordane-related compounds (sigma CHL) and dieldrin concentrations. Hepatic -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 -tocopherol status in Arctic top predators.