Obesity in Labrador Retrievers and People, A Genetic Similarity?
A new study has discovered one reason why Labrador retrievers, more than other dogs, tend to be obese. The reason happens to involve genetics, and it turns out that some obese people have a variation in their genes similar to that seen in these dogs.
Obesity in dogs, as in people, is a health risk because it can reduce lifespan and be associated with health problems ranging from heart disease to arthritis, diabetes, and limited mobility. While some dogs “wolf” down their food and are good at begging for more, Labrador retrievers and flat-coated retrievers, who are related to Labs, tend to be especially fond of eating.
This love affair with food has made them more likely to obese than other canine breeds, even when dog owners restrict food consumption and increase exercise. To uncover the cause of obesity in these dogs, a team of researchers at the University of Cambridge (United Kingdom), under direction of Eleanor Raffan, a geneticist and veterinary surgeon, conducted two studies.
First obesity study
In the first study, the investigators examined three genes in 15 obese and 18 lean Labrador retrievers. These genes had previously been found to be associated with weight and obesity in humans.
Most of the obese dogs had a missing DNA section in one of the genes—POMC. Scientists believe this anomaly makes it impossible for the dogs to produce beta-MSH and beta-endorphin, two neuropeptides that turn off hunger after eating.
A minority of obese people also do not have a similar segment of their POMC gene.
Second obesity study
Next, the team evaluated 310 Labrador retrievers and observed the following:
- Not all of the dogs with the DNA mutation were obese
- Some of the Lab were obese even though they were not missing the POMC segment
- However, dogs with the modified gene weighed on average 4.5 pounds more than dogs without the mutation
Do you have a Labrador who loves to eat? When the authors asked owners of Labrodors with the deleted gene about their dog’s behavior around food, they said their companions were greatly attentive at mealtimes, frequently begged for food, and had a heightened tendency to search for food scraps.
According to Raffan, these findings suggest there is “a hardwired biological reason” Labradors are more obsessed with food than other breeds, even though some dogs without the mutation were also food-focused.
Is this mutation a good thing?
Labrador retrievers are often used as assistance dogs, and along with their loving disposition, one reason may be the presence of this gene mutation. In fact, in a study of 81 assistance Labrador retrievers, more than 75 percent of them had the anomaly.
Therefore, Labradors with the missing DNA segment may be more suitable for training as an assistance dog because they are highly food motivated. Since the training involves food rewards, it seems like a perfect fit, although obesity is still a health problem.
In Labrador retrievers as in people, genetics are not the final word. Raffan noted that it’s possible to keep a dog with the mutation slim by being conscientious about portions and exercise, advice that also can apply to people.
According to one of the study’s senior authors, Stephen O’Rahilly, “Further research in these obese Labradors may not only help the well-being of companion animals, but also carry important lessons for human health.” In the meantime, why not take your dog for a walk!
Raffan E et al. A deletion in the canine POMC gene is associated with weight and appetite in obesity prone Labrador retriever dogs. Cell Metabolism 2016 May 3
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