Nutro products were heavily involved in the melamine recalls. Our dog had a bad intolerance to the corn in them. When there's food intolerances and allergies it's usually to corn, wheat, soy and chicken.
What was the diagnosis, or what did your vet feel was wrong?
A large breed puppy or else (what we feed here) Kirkland Signature. 4health or Diamond Naturals if you don't have a Costco card.
You don't want the puppy growing too fast anyway due to skeletal development.