There is not degree to be earned anywhere in dog nutrition. Vet's can study animal nutrition outside their regular studies but are not given more than one semester in ANIMAL nutrition in veterinary college.
We have many pet food companies that hire veterinarians to work for them. Anyone at any level who is paid by a company is going to represent the company's best interest first. The kind of thing "the dentist" points out about pet foods are things that are common knowledge. The ingredients and the kind of side effects certain ingredients have been found to cause are easy enough to find. The fact that it is a dentist that puts the information together for people to read for themselves means nothing. They are simply facts that anyone can make their own decisions about.
I would guess that few of us here went to school and for any length of time to lean how to cook for ourselves and our families although I'm sure many of of us have read up on human nutrition at one time or another. Are humans less complicated to feed than dogs?
If anyone is interested in learning more about the pet food industry from some people who have invested a lot of time and money investigating the industry and how it works with the FDA here is a link to a good website:
Purina Sues Blue Buffalo | Truth about Pet Food