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Although mainly used in archeology and human medicine, recent studies have shown that not only humans but also captive animals exhibit a shift in isotopic ratios of e.g. Cu and Zn in blood when suffering from a deterioration of health. For example, previous studies have shown that the ratio of 65Cu and 63Cu in blood from domestic canines was significantly lower in dogs diagnosed with cancer compared to healthy dogs, and similar results have also been shown for captive wild felids. Yet studies on blood chemistry from wild animals in general, and on Arctic wildlife specifically, are still scarce and the isotopic ratios within such samples, including potential shifts, are entirely unknown. Our aim was therefore to quantify, for the first time, the 65Cu/63Cu ratio in blood from wild and captive muskoxen (Ovibos moschatus) and to test the hypothesis that the isotopic ratio would decrease with a deterioration of health. To test this notion, we collected blood from muskoxen that were either captive (i.e. from zoos in Sweden and Denmark), wild (i.e. from long-term wildlife monitoring program in North-East Greenland), or culled (i.e. from population management programs in Norway). These samples were then analyzed for total-chemistry using iCapTQ/HR-ICP-MS analysis and for Cu-isotopic composition using MC-ICP-MS analysis. In addition, ecological traits (i.e. age, sex, body weight, body condition) were registered and blood serum analysis (i.e. SAA, cortisol levels) were performed to provide information on the health status of each animal. Our preliminary results show that the measured 65Cu/63Cu signatures range from -1.55 to 0.22, and appear to cluster with sample group (wild vs captive) in which the captive animals consistently showed higher 65Cu/63Cu signatures vs the wild or culled animals. We also found support for our hypothesis that there is a link between the Cu-isotopic signature and the overall health of the animal as the lowest detected Cu-isotopic signatures were found in animals with low body condition scores and with relatively low values of Fe, yet more data are needed to fully confirm this. Although preliminary, these results still indicate that Cu-isotopic ratios in animal blood can serve as a diagnostic tool to determine the health of large wildlife, which in turn could be used to facilitate and improve wildlife management programs in remote locations such as the Arctic.
Hansson et al. (Sat,) studied this question.