Does the nutrition profile of vitamins, fatty acids and microelements counteract the negative impact from organohalogen pollutants on bone mineral density in Greenland sledge dogs ( Canis familiaris)?

Abstract

There is a great need for understanding the impact from dietary OHCs (organohalogen compounds) on bone mineral composition – and thereby osteoporosis – in especially arctic wildlife such as polar bears ( Ursus maritimus) as well as humans. For that purpose, we measured BMD (bone mineral density) by DXA scanning (g/cm − 2 ) in 15 age and weight normalized sledge dog ( Canis familiaris) bitches and their 26 pups divided into a control group ( n = 26) given 50–200 g/day clean pork ( Suis scrofa) fat and a treated group ( n = 15) given 50–200 g/day OHC polluted minke whale ( Balaenoptera acutorostrata) blubber as main lipid sources. The results showed that BMD increased significantly with age (linear regression: p < 0.0001, r 2 = 0.83, n = 41) while no sex difference was found in the F-generation (two-way ANOVA: all p > 0.3). No differences in BMD femur or BMD vertebrae between exposed and control individuals in the bitch generation were found (linear mixed effect model: both p > 0.38). Likewise, no difference between exposed and control subadults and juveniles in the F-generation was found (two-way ANOVA: all p > 0.33). Correlation analyses between BMD femur, BMD vertebrae and groups of OHCs, respectively, did not show any statistically significant relationships nor a clear or decreasing trend (Pearson's: p: 0.07–0.78; r: − 0.2–0.59; n: 10–18). As the groups were similar regarding genetics, age and sex are the only factors that can explain this observation. Either the pollutants did not have an impact on BMD using the present time frame and OHC concentrations (threshold levels not reached), or the difference in food composition (mainly vitamins and n3 fatty acids) conceal the potential OHC impact on BMD. Such information is important when evaluating the positive and negative health consequences from eating polluted marine species.