Quote:
Originally Posted by chilibee  Well yes and no---the pathways are constructed the same way--unlike cows that that have 6 stomachs--and thus are able to digest grains. As far as the enzymes go--please elaborate. |
From the link I posted above
:
Dogs and cats have the internal anatomy and physiology of a carnivore (Feldhamer, G.A. 1999. Mammology: Adaptation, Diversity, and Ecology. McGraw-Hill. pg 260.). They have a highly elastic stomach designed to hold large quantities of meat, bone, organs, and hide. Their stomachs are simple, with an undeveloped caecum (Feldhamer, G.A. 1999. Mammology: Adaptation, Diversity, and Ecology. McGraw-Hill. pg 260.). They have a relatively short foregut and a short, smooth, unsacculated colon. This means food passes through quickly. Vegetable and plant matter, however, needs time to sit and ferment. This equates to longer, sacculated colons, larger and longer small intestines, and occasionally the presence of a caecum. Dogs have none of these, but have the shorter foregut and hindgut consistent with carnivorous animals. This explains why plant matter comes out the same way it came in; there was no time for it to be broken down and digested (among other things). People know this; this is why they tell you that vegetables and grains have to be preprocessed for your dog to get anything out of them. But even then, feeding vegetables and grains to a carnivorous animal is a questionable practice.
Dogs do not normally produce the necessary enzymes in their saliva (amylase, for example) to start the break-down of carbohydrates and starches; amylase in saliva is something omnivorous and herbivorous animals possess, but not carnivorous animals. This places the burden entirely on the pancreas, forcing it to produce large amounts of amylase to deal with the starch, cellulose, and carbohydrates in plant matter. Thus, feeding dogs as though they were omnivores taxes the pancreas and places extra strain on it, as it must work harder for the dog to digest the starchy, carbohydrate-filled food instead of just producing normal amounts of the enzymes needed to digest proteins and fats (which, when fed raw, begin to "self-digest" when the cells are crushed through chewing and tearing and their enzymes are released).
Nor do dogs have the kinds of friendly bacteria that break down cellulose and starch for them. As a result, most of the nutrients contained in plant matter—even preprocessed plant matter—are unavailable to dogs. This is why dog food manufacturers have to add such high amounts of synthetic vitamins and minerals (the fact that cooking destroys all the vitamins and minerals and thus creates the need for supplementation aside) to their dog foods. If a dog can only digest 40-60% of its grain-based food, then it will only be receiving 40-60% (ideally!) of the vitamins and minerals it needs. To compensate for this, the manufacturer must add a higher concentration of vitamins and minerals than the dog actually needs.