Many Labradors feel hungry all the time due to genetic mutation, University of Cambridge research has shown

A quarter of Labrador retriever dogs feel hungry all the time and burn fewer calories due to a genetic mutation, University of Cambridge research has found.

The combination drives obesity in the dogs and means owners must be particularly strict with feeding and exercising them.

The mutation affects the POMC gene, which plays a key role in hunger and energy use, and is found in 25 per cent of Labradors and 66 per cent of flatcoated retriever dogs.

Researchers have previously shown that it increases interest in food and the risk of obesity and the new study reveals how profoundly it changes the way these dogs behave around food, showing that although they do not need to eat more to feel full, they are hungrier in between meals.

Dogs with the POMC mutation were also found to use around 25 per cent less energy at rest than dogs without it, which means they do not need to consume as many calories for a healthy body weight.

“We found that a mutation in the POMC gene seems to make dogs hungrier,” said Dr Eleanor Raffan,from the Department of Physiology, Development and Neuroscience who led the study. “Affected dogs tend to overeat because they get hungry between meals more quickly than dogs without the mutation.

“All owners of Labradors and flatcoated 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 POMC mutation alters a pathway in the dogs’ brains associated with body weight regulation, triggering a starvation signal that tells their body to increase food intake and conserve energy, despite this being unnecessary.

The results are published in the journal Science Advances.

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.”

Owners should keep their retrievers distracted by spreading out each daily food ration, for example, by 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 per cent 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.