Try this site- Dog Food Reviews and Ratings | Dog Food Advisor
It's one of the best resources for choosing a dog food, they analyze every ingredient. Purina Pro Plan Savor, got a very low rating of 2.5 stars. I'd look for something with at least 4 stars.
"When we speak of bulldogs, the words that fit, Are those like courage, stamina and grit."-Floyd Boudreaux
"How many times have we heard the phrase 'I felt so Good I could lick the world!' Well, the American Pit Bull Terrier feels like that all the time!" - Richard F. Stratton