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 involved in starch digestion and glucose absorption changed (mutated). Nevertheless, a diet more similar to that of wolves could offer advantages for modern dogs. Dogs are descended from wolves, but their diet has changed significantly since domestication. Wolves are strict carnivores, similar to cats, while dogs are considered omnivores. Scientists from Wageningen University and Research University and Research Utrecht have studied the diets of wolves and dogs to identify similarities and differences. These findings can help improve and optimize commercial dog food.
Flexible metabolic system
The domestication of the dog began between 13,000 and 17,000 years ago, when gray wolves discovered food scraps near human camps. The dog evolved into an omnivore due to the availability of both animal and plant food sources. Modern wolves remain almost exclusively carnivores, with highly variable nutrient intakes: they can go long periods without food and consume enormous quantities after a successful hunt. This "abundance and scarcity" lifestyle has led to an extremely flexible metabolism in wolves, allowing them to cope well with variable nutrient requirements. This adaptable metabolic system is still present in modern dogs.
Close relationship
Selective breeding has led to the development of a huge variety of dog breeds over the past centuries. Most dogs bear little resemblance to their ancestors, 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. During domestication, three genes involved in starch digestion and glucose uptake were modified, as the research shows. In terms of starch digestion, domesticated dogs are increasingly resembling omnivores such as humans, rats, and pigs. While modern dogs have an omnivorous diet, they remain closely related to their carnivorous ancestor, the gray wolf.
Diet
Wolves are pure carnivores: their feces usually consist of less than 3 percent plant material. The natural diet of wild wolves has been determined based on prey composition, stomach contents, and fecal analysis from various literature sources. The nutrient profile of wild wolves is summarized in the table. Protein digestibility varies: muscle tissue and organs are easily 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 significantly from that of domestic dogs, which obtain 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 in dogs is independent of breed: both large and small breeds choose an average of 63 percent energy from fat and 7 percent from carbohydrates. The diet of domesticated cats differs less from that of wild cats: the energy ratio for wild cats is 52:46:2, and for domesticated cats, 52:36:12. Therefore, compared to both wolves and cats, dogs show a clear preference for high-fat foods. Storing fat reserves is crucial for survival during food shortages. The amount and type of food a wild wolf eats varies greatly: after a successful hunt, they can consume up to 22 percent of their body weight, with a preference for organ meat. When food is scarce, they eat the remains of old prey, including more skin and bone. Dogs can still endure long fasts and recover quickly when food becomes available. Due to their "abundance or scarcity" lifestyle, wolves were likely originally better than wild cats at utilizing less nutritious human waste.
Commercial food
The composition of dog food differs in some respects from the natural wolf diet; it contains less energy, much of which comes from starch in cooked grains. Dogs process starch better than wolves, but the health consequences of high glucose intake 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 low in omega-3 fatty acids. A possible deficiency of omega-3 fatty acids (EPA and DHA) in dog food could negatively impact the immune system. The indigestible components 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 the microbiota on physiology, the immune system, and behavior, the researchers recommend further research into the effects of fiber types in dogs and their health.
Wolf diet
A well-known theory in human nutrition posits that the modern diet deviates too much from the hunter-gatherer pattern of the past. A return to a paleo diet could reduce the risk of lifestyle diseases (such as diabetes, obesity, and tooth decay), according to this hypothesis. This theory has not yet been conclusively proven, but Bosch, Hendriks, and Hagen-Plantinga recommend investigating whether a "wolf-like" diet offers advantages for modern dogs. Dogs are well-adapted to starchy foods, but under less than optimal circumstances, such as old age or chronic illnesses, a modified diet could be beneficial. However, the longevity that domestic animals now reach is unnatural, so a wolf-like diet is unlikely to offer any advantages for older dogs, the authors expect.
Source: Carolien Makkink Petfood Magazine.
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