Currently, dogs that live in homes are fed with feed intended for their species, but in many cases, this diet is complemented with other types of food, many of them aimed at humans. Is the digestive system in dogs prepared for this feeding?

It seems that dogs can eat everything, although, in the end, they end up showing liver or kidney problems that, hardly, we will relate to an inadequate diet.

How is the digestive system in dogs?

The digestive system in dogs is primarily designed for meat consumption. This is formed by the gastrointestinal tract, which begins with the mouth and, subsequently, is divided into the esophagus, stomach, small intestine, and large intestine. Also, we find the attached glands, such as the liver, pancreas, and gallbladder.

Macroscopically, there are not many differences, but some very descriptive ones, such as teeth and digestive tract length, specifically the size of the small intestine.

All dogs, in adulthood, have the same number and type of teeth, in total 42 teeth. These are:

  • 12 incisors
  • Four fangs
  • 16 premolars.
  • Ten molars

Despite having the same amount of teeth, the bite varies. Thus, some dogs close their mouths by placing their teeth in the form of a clamp, so that the incisors rub against each other. Others, when closing the mouth, have a clamp-like bite, so that the inner edge of the upper teeth rub the outer side of the lower incisors.

Occasionally, the lower jaw exceeds the upper, which is known as prognathism, very typical of breeds such as boxer or bulldog. Also, we can find the opposite case, the upper jaw that is far ahead of the lower one, what is called dogmatism. This feature is always considered a defect in the dog.

Continuing with the digestive tract, after the esophagus, we find the stomach. The internal walls of this organ have very rough roughnesses that help crush the food bolus that comes from the mouth. This is not very digested because dogs chew food.

Later, in the intestine, a large number of enzymes are released that collaborate with the chemical digestion of food. Some current studies have found that many dog ​​breeds begin to show a higher concentration of enzymes intended for the metabolism of hydrocarbons or carbohydrates, in addition to those responsible for digesting proteins.

On the other hand, the intestine of dogs is very short, a typical characteristic of carnivores, although certain breeds of dogs have more elongated. Also, the intestinal flora that we find in the intestines of dogs is typical of predatory animals.

Is the dog a carnivorous or omnivorous animal?

If we look at the composition of any feed intended for dogs in a supermarket, we can verify that they carry a wide variety of ingredients, from meats of various types to cereals or legumes. This, together with that practically everything that we give to a dog will eat it, can make us think that the dog is an omnivorous animal, but no. Dogs are facultative carnivorous animals.

The nutritional nature of the dog, that is, that they are optional carnivores, has several reasons:

  • The length of your intestine is concise, from 1.8 to 4.8 meters, for which you always have to take into account the breed, since this length, the permeability of the nutrients, and the type of microbiota will vary. On the contrary, an omnivorous animal, like the human being, has an intestine between 5 and 7 meters.
  • Very sharp teeth form the dentition of a dog. Its fangs are prepared to tear the food, and its molars, keen, break the food in a few bites so that it falls more quickly.
  • Carnivorous animals have a different intestinal flora than herbivorous or omnivorous animals. This intestinal flora serves, among many other things, to help ferment certain nutrients, such as carbohydrates. The fermentative carbohydrate pathways in dogs are very poor.
  • The animals’ brain works mainly thanks to the glucose derived from the digestion of carbohydrates. Dogs have alternative metabolic pathways through which they produce glucose from proteins.

So, if the dog is not omnivorous, why can it assimilate some plant-based nutrients?

Epigenetics, how does it influence the digestive system of dogs?

So far, it is clear that the dog is a typically carnivorous animal, but why can they assimilate other nutrients that are not of animal origin?

To explain it, we must understand what epigenetics is. This concept refers to the force that the environment exerts on the genetic information of living beings. A simple example to follow is how turtles are born male or female according to the temperature at which they have developed.

Something similar has happened with dogs, but widespread over time, more than 10,000 years. During the process of domestication of the dog, especially in its beginnings, they have been feeding on ‘human waste.

This fact has exerted pressures that could cause changes on the synthesis of enzymes responsible for the digestion of nutrients, which has adapted dogs to survive by eating a more varied diet. This has made that, today, dogs can assimilate many nutrients of plant origin; hence, they are considered optional carnivores.