DOGS are OMNIVORES!

[richie]

Excellent information here, I just wanted to clarify the enzymology reference. The amylase (present in human saliva, and in most animals' guts) digests starches only, converting them into sugar. They have NO effect on cellulose.

Salivary amylase activity explains why when we chew a cracker a long time, it starts to taste sweet -- for humans, digestion does start in the mouth and saliva and good chewing goes a long way to digest our starchy foods. Dogs do not have this enzyme in their saliva, which makes starch digestion quite a bit more difficult for them.

Dogs still can absorb sugars just fine, but like any other animal, if the cellulose cell walls are not ruptured, the sugars in fruits and vegetables are not readily available. As was well documented here, the canine dentition is not well adapted to this task, unlike our teeth, which do a decent job on raw fruits and veggies.

To say amylases are active on plant material is correct, but not specific and could be confusing. These enzymes have NO activity on cellulose, which is the cell wall component of plant materials such as grass. In fact, I don't believe any animal can digest cellulose without microbiological help. The termites that eat wood, the cows that eat grass, etc. all rely on microorganisms in their guts (in the rumen of cows for example) to do the actual work or breaking down cellulose.

[richie]

Someone mentioned that dogs eat poop which is a 'naturally processed' vegetable matter... which reminded me...

I have noticed that nearly all dogs seem to LOVE fresh goose poop, especially during the times of the year when the grass is actively growing and the goose poop is mostly bright green. I can believe the argument that fruits are eaten for their sweet tasting sugar content, but what is it in those tasty morsels of crap that most dogs seem to find irresistible? Maybe there is some nutrition in there, that the dogs can absorb once the geese have partially processed them through their gizzards??? None of the dogs who enjoy these snacks seem to suffer from them, but who can tell if they benefit?