High protein diet may harm polar bears

A captive polar bear at the Columbus Zoo and Aquarium in Powell, Ohio, shows identical preferences in fat and carbs/protein ratio with polar bears in the wild as it chooses from pure lard lumps and seal meat lumps. Credit: Devon Sabi, Columbus Zoo.

A high-protein diet appears to be linked to kidney disease and a shorter lifespan for captive polar bears, a relationship similarly suspected in humans, according to a review led by Washington State University wildlife biologist Charlie Robbins.

The paper published in zoo biology, takes a closer look at what zoos fed to polar bears, showing that they mostly provided a diet intended for big cats, containing about 2-3 parts protein to 1 part fat, a reflection of what was observed in the wild.

“Zoos have made some assumptions in the past about the nutritional requirements of polar bears because their diet is restricted to animals,” said Robins, professor and founder of the Bear Center at WSU. “But, unlike cats, they don’t need and can’t tolerate high protein.”

Polar bears feed only on seals and are classified as carnivores. But recent research has shown that polar bears, like other bears, have nutrition and physiology closely with primates, including humans.

Previous field studies led by Karen Rudd, a former graduate student at WSU Bear now with the USGS, showed that wild polar bears preferentially consume a diet of two parts fat to one part protein that maintains protein levels in the range low. requirements. These results have been published in Scientific Reports In July 2021.

“Although we learned that polar bears were selected to sear their prey, this was the first time we were able to determine how much lipid they were actually consuming,” Robbins said. “When it comes to feeding polar bears, the general mentality has been that they are carnivores. No one really paid attention to how much protein they might need, let alone the limitations on how much they could tolerate.”

In the current paper, the researchers suggest that both polar bears and their closest relative, the grizzly bear, require relatively low levels of protein similar to the requirements of humans, primates and other species of omnivorous animals.

When captive bears were offered lumps of pure lard and lumps of high-protein meat, they preferred the same fat-to-protein ratio they would normally consume in the wild.

Close examination of the death records of captive polar bears of both sexes clearly showed that the most common cause of death was kidney disease. Bears dying of kidney disease died 10 years earlier than bears that did not have kidney disease. Liver disease and cancer were the second most common causes of death.

Of the more than 600 wild bears examined, the team found no evidence of liver or kidney disease.

“The list of premature deaths between the sexes that is limited to two major members raised many red flags for us,” said Robbins, who has researched the feeding of grizzly and polar bears for more than 35 years.

The team worked with Mazuri Exotic Animal Nutrition and nutrition expert, Troy Tollefson who also earned a Ph.D. while working at the WSU Bear Center, to develop a dry kibble with a lipoprotein equivalent to what they would naturally consume in the wild.

The authors suggest that zoos adopt this food or other alternatives that mimic the lipoprotein ratio found in the wild for captive polar bears, while monitoring the new system carefully to see if it improves the bears’ health and longevity.

WSU’s research was used to develop food, but none of the WSU scientists had any commercial interest in the company or its products.

Polar bear Boris has three severed teeth at the Washington Zoo

more information:
Charles T. Robins et al., New Insights for the Nutritional Management of Polar Bears (Ursus maritimus) and Brown Bears (U. arctos), zoo biology (2021). DOI: 10.1002 / zoo.21658

Karyn D. Rode et al, Vital and health effects of excessive protein consumption restricting dietary adaptation in a major predator, Scientific Reports (2021). DOI: 10.1038 / s41598-021-94917-8

Provided by Washington State University

the quote: High-protein diet may harm polar bears (2022, January 19) Retrieved January 20, 2022 from https://phys.org/news/2022-01-high-protein-diet-polar.html

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