This is really interesting research -- which in part shows that dogs developed the ability to digest grains early on. Not an argument that dogs should get a cereal-full diet -- but does suggest that a firm 'anti-grain in dog food' stance -- which gets a lot of mileage on the internet!! -- is actually misguided and that intolerance for grains in dog food is likely, not a common issue at all. Here's a WebMD blog post, passed along by Telegraph columnist Pet the Vet. The blog post is easy to understand and is very balanced in suggesting the directions one could go with feeding -- and cautioning strongly against most dog foods that simply contain poor quality feed grade ingredients:

http://www.petmd.com/blogs/thedailyv...s-and-starches

Interestingly, genetic sequencing shows that dogs have a number of genetic changes in their genome that enables them to digest grains and starch and thus benefit from their vitamins and minerals.

a study published in Nature magazine proved that dogs’ domestication complements environmental and geographical changes associated with their role as companions to humans. It’s proven in their genes, which have evolved similarly to man’s and reflect dogs’ ability to digest grains and starches.

...

“Ten genes with key roles in starch digestion and fat metabolism also show signals of selection. We identify candidate mutations in key genes and provide functional support for an increased starch digestion in dogs relative to wolves. Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs."
Even though today’s dogs can digest grains and starches, I don’t recommend that such nutrients form the majority of a dog’s diet. Any grains or starches made to be consumed by our pets should be whole-food based, cooked, and included in a small to moderate quantity (30% or less of the volume of a particular meal), complementing the larger percentage of meat, vegetable, and fruit ingredients.

Although commercially available and home prepared diets that are 100 percent free of grains and starches are popular, there are nutritional benefits stemming from their inclusion. Whole grains like brown rice, barley, etc., are good sources of minerals (Selenium, Manganese, etc.) and can even serve as substrates (pre-biotics) on which beneficial bacteria (pro-biotics) grow. Starches like russet and sweet potatoes, banana, etc., are rich in vitamins (A, B6, E, etc.) and minerals (Potassium, Manganese, etc.).
This research is ironic in timing, as an Irish distributor of (excellent) raw food just wrote a booklet arguing how dogs are almost entirely carnivores. This research suggests not. It also would not match research of various canid diets which showed that coyotes for example -- who would probably be similar to early domestic dogs in that they are opportune eaters and hang about close to human settlements, scavenging -- eat a certain amount of fruit etc.