Bears hibernate ‘with bacterial help
Researchers have discovered seasonal changes in the gut microbes of brown bears, which apparently help the beasts cope with the demands of hibernation.
Bears feast and gain weight in the warm months, ready for the big winter doze.
In faecal samples from 16 wild bears, scientists found a bug population that was more suited to depositing fat in summer, and burning it in winter.
Senior author Fredrik Bäckhed, said it was not a huge surprise to see gut flora change with the seasons – but this is the first time anyone has revealed a role for these different bugs in the energy metabolism of a hibernating animal.
“We know that the microbiota is very responsive to what we eat,”
“So if a bear eats a lot in the summer and it doesn’t eat in the winter, then there should be an altered microbiota. What we learn from our study is that it appears that the altered microbiome can contribute to the altered adiposity (fattiness).”
Despite this insight, Prof Bäckhed said his team’s findings were not going to help tackle human obesity.
“I don’t think that this study will have direct implications for obesity, as the summer microbiota will make you fat and the winter insulin resistant.
“But perhaps we can find clues for treating malnutrition from the summer bacteria, and help patients with anorexic disorders – including cancer patients.”
Specialist expertise was required; it is no small undertaking to wake up a hibernating bear and take a sample of its faeces.
So when researchers transfer foreign microbes into the mice, they know that introduced bugs are the only ones present.
Strikingly, just like the bears themselves when they fatten up every year, the mice with summer-bear bacteria remained “metabolically healthy”.
“Although they gained more fat mass, it didn’t impair their glucose tolerance,” said Prof Bäckhed.
In other words the insulin system, which regulates the body’s use of blood sugar and causes diabetes if it goes haywire, was still in working order.
Source: BBC
N.H.Khider