The numerous dietary choices for your pet can be daunting but if you pick an AAFCO approved food made by a manufacturer with a long track record, odds are good that you will find a suitable food for your pet. Most of the large pet food companies employ full time veterinary nutritionists and have very high quality control standards. That is not to say that a small company cannot produce nutritious and high quality food, but you should check out their website if it’s a company that is not familiar to you. Take the time to research, and ask your veterinarian if you have specific questions or concerns.
(above is an excerpt from)
https://www.mspca.org/angell_services/choosing-the-right-diet-for-your-pet/
Another site you may find helpful http://skeptvet.com/Blog/category/nutrition/
