Dog vs. wolf
Research by Guido Bosch, Wouter Hendriks, and Esther Veninga-Hagen shows that during the domestication period from wolf to dog, three genes underwent changes (mutations) that play a role in the digestion of starch and the absorption of glucose. Nevertheless, a diet that more closely resembles that of wolves could offer benefits for contemporary dogs. Dogs are descendants of wolves, but their diet has changed significantly since domestication. Wolves are strict carnivores, similar to cats, while dogs are considered omnivores. Scientists from the universities in Wageningen and Utrecht have examined the diets of wolves and dogs to map out similarities and differences. These findings may help in improving and optimizing commercial dog food.
Flexible metabolic system
The domestication of the dog began between 13,000 and 17,000 years ago, when gray wolves found food scraps at human camps. The dog evolved into an omnivore because both animal and plant food sources were available. Modern wolves remain almost exclusively carnivores, with a highly variable nutrient intake: they can endure long periods without food and consume enormous quantities after a successful hunt. This 'feast and famine' lifestyle has led to an extremely flexible metabolism in wolves, allowing them to handle variable nutrients well. This adaptable metabolic system is still present in contemporary dogs.
Close relationship
Selective breeding has resulted in an enormous variety of dog breeds over the past few centuries. Most dogs barely resemble their ancestors in appearance, but dogs and wolves can still mate and produce fertile offspring. Therefore, dogs are considered a subspecies of wolves; they belong to the same species and share a strong genetic similarity. In the domestication phase, three genes involved in starch digestion and glucose absorption were adapted, as the research shows. In terms of starch processing, domesticated dogs increasingly resemble omnivores such as humans, rats, and pigs. On one hand, modern dogs have an omnivorous diet; on the other hand, they remain closely related to their carnivorous ancestor, the gray wolf.
Dietary pattern
Wolves are pure carnivores: their feces typically consist of less than 3 percent plant material. The natural diet of wild wolves has been determined based on prey composition, stomach content, and fecal analysis from various literature sources. The nutrient profile of free-living wolves is summarized in the table. The digestibility of proteins varies: muscle tissue and organs are highly digestible, while proteins in skin, hair, and bones are difficult to break down. The table shows that the diet of wild wolves has a protein:fat:carbohydrate ratio of 54:45:1 on an energy basis. This ratio differs sharply from that of domesticated dogs, which derive 30 percent of their energy from protein, 63 percent from fat, and 7 percent from carbohydrates. It is striking that the preference for this nutrient ratio is independent of dog breed: both large and small breeds choose, on average, 63 percent energy from fat and 7 percent from carbohydrates. The diet of domesticated cats differs less from that of wild cats: the ratio for wild cats is 52:46:2, and for house cats it is 52:36:12 on an energy basis. Dogs therefore show—compared to both wolves and cats—a clear preference for high-fat food. Storing fat reserves is crucial for survival during food shortages. The amount and type of food a wild wolf eats varies enormously: after a successful hunt, they can ingest up to 22 percent of their body weight, with a preference for organ meat. During food scarcity, they eat remnants of old prey, including more skin and bones. Dogs can still endure long periods of fasting and recover quickly when food is available. Due to their 'feast or famine' lifestyle, wolves were originally probably better than wild cats at utilizing less nutritious human waste.
Commercial food
The composition of dog food differs in several respects from the natural wolf diet; it contains less energy, a large portion of which comes from starch from cooked grains. Dogs process starch better than wolves, but the health consequences of high glucose absorption from starch are unclear. Dog food has slightly less fat than wolf food, and this fat is often plant-based, rich in omega-6 fatty acids and poor in omega-3 fatty acids. A potential shortage of omega-3 fatty acids (EPA and DHA) in dog food could have negative effects on the immune system. The indigestible parts also differ: plant fibers ferment differently than indigestible animal components (such as cartilage and collagen), which affects the gut microbiota. Because of the impact of microbiota on physiology, the immune system, and behavior, the researchers recommend more study into the effects of fiber types in dogs and what they do to their health.
Wolf diet
A well-known theory in human nutrition states that the modern diet deviates too much from the hunter-gatherer pattern of the past. According to this hypothesis, a return to a paleo diet could lower the risks of lifestyle diseases (such as diabetes, obesity, and tooth decay). This theory has not yet been convincingly proven, but Bosch, Hendriks, and Hagen-Plantinga recommend investigating whether a 'wolf-like' diet offers benefits for modern dogs. Dogs are well adapted to starch-rich food, but under less than optimal conditions, such as old age or chronic illnesses, an adjusted diet could be beneficial. However, the high age that pets now reach is not natural, so the authors do not expect a wolf diet to offer benefits for older dogs.
Source: Carolien Makkink Petfood Magazine.
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