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Dalhousie University researchers are providing new insight into how climate change, captivity and dietary alterations affect the gut microbiome and health of wild and captive populations of polar bears.

Shrinking Arctic Sea ice coverage and extended ice-free seasons reduce the area and window of time polar bears can spend on the ice platform. That is causing some populations to increase their land use to hunt for terrestrial animals, resulting in a switch from a fat-rich diet of seals to a low-fat, high protein diet for an extended period.

If sea ice fails to refreeze, some populations of polar bears will remain onshore permanently without access to the preferred high-fat diet. 

In one of the first studies of its kind, PhD student Jing Lu and Associate Professor Stephanie Collins in Dal's Department of Animal Science and Aquaculture, collaborated with colleagues at the Cochrane Polar Bear Habitat, the Churchill Northern Studies Centre, and Agriculture and Agrifood Canada to compare the fecal microbiome -- microbes living in the lower digestive tract that are a good indicator of health -- of captive polar bears with the wild population.

In this study, the captive bears -- named Inukshuk, Ganuk, Henry and Eddy -- were fed a higher protein mackerel-based diet, simulating the habitat and lifestyle changes wild bears may be forced to undertake should they become landlocked.

Within the captive population, individual differences were more pronounced than seasonal or annual variations.  The wild and captive polar bears had distinctly different microbial populations. As with people, the gut microbiome of polar bears can be affected by where they live and what they eat. In the case of this study, the very different habitats and differences in nutrient balance of their diets (high fat vs high protein) are two major reasons for these differences.

Dr. Collins and Jing Lu are available to discuss this newly published research and how comparing the fecal microbiome of captive polar bears with the wild population can help us understand the implications of climate-driven dietary and nutritional changes for this sentinel species.

Photos are available by request. Journal article: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0311518

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Media contact:

Alison Auld
Senior Research Reporter
Dalhousie University
Cell: 1-902-220-0491
Email: alison.auld@dal.ca