Genetic mutation in 25% of Labradors hard-wires them for obesity – study

Around a quarter of Labradors face a “double whammy” of feeling hungry all the time and burning fewer calories due to a genetic mutation, new research suggests.

Scientists say this combination drives obesity and means dog owners should be particularly strict with feeding and exercising their dogs to keep them slim.

The mutation is in a gene called POMC, which plays a key role in hunger and energy use.

According to the study, around 25% of Labradors, and 66% of flat-coated retriever dogs have the mutation, which researchers previously showed causes increased interest in food and risk of obesity.

The new study found the mutation changes how the dogs behave around food.

They do not need to eat more to feel full, but they are hungrier in between meals, the researchers found.

In addition, dogs with the mutation were found to use around 25% less energy when resting than dogs without it.

The finding indicates they do not need to eat as many calories to maintain a healthy body weight.

Dr Eleanor Raffan, a researcher in the University of Cambridge’s Department of Physiology, Development and Neuroscience, who led the study, said: “We found that a mutation in the POMC gene seems to make dogs hungrier.

“Affected dogs tend to overeat because they get hungry between meals more quickly than dogs without the mutation.”

She added: “All owners of Labradors and flat-coated retrievers need to watch what they’re feeding these highly food-motivated dogs, to keep them a healthy weight.

“But dogs with this genetic mutation face a double whammy: they not only want to eat more, but also need fewer calories because they’re not burning them off as fast.”

The study, published in Science Advances, found that the gene mutation altered a pathway in the dogs’ brains associated with body weight regulation.

The mutation triggers a starvation signal that tells their body to increase food intake and conserve energy, despite this being unnecessary.

Dr Raffan said: “People are often rude about the owners of fat dogs, blaming them for not properly managing their dogs’ diet and exercise.

“But we’ve shown that Labradors with this genetic mutation are looking for food all the time, trying to increase their energy intake. It’s very difficult to keep these dogs slim, but it can be done.”

The researchers suggest owners can keep their retrievers distracted from this constant hunger by spreading out each daily food ration.

This could be done through using puzzle feeders or scattering the food around the garden so it takes longer to eat.

In the study, 87 adult pet Labrador dogs – all a healthy weight or moderately overweight – took part in several tests including the sausage in a box test.

They were first given a can of dog food every 20 minutes until they chose not to eat any more.

All of the pets ate a lot of food, but the dogs with the gene mutation did not eat more than those without it.

This showed that they all feel full with a similar amount of food.

On a different day, the dogs were fed a standard amount of breakfast, and three hours later they were offered a sausage in a clear plastic box and their behaviour was recorded.

The dogs could see and smell the sausage, but could not eat it.

Researchers found that dogs with the mutation tried significantly harder to get the sausage from the box than dogs without it, indicating greater hunger.

The dogs then slept in a special chamber that measured the gases they breathed out.

This revealed that the animals with the mutation burn around 25% fewer calories than dogs without it.

Researchers say the new findings are consistent with reports of extreme hunger in humans with POMC mutations, who tend to become obese at an early age and develop a host of clinical problems as a result.

The research was funded by The Dogs Trust and Wellcome.