Depending on the size of your dog as an adult you are going to want to feed them a formula that will cater to their unique digestive needs through the various phases of their life. Many dog food companies have breed-specific formulas for small, medium, large and giant breeds. The American Bully is a medium breed and has a lifespan of 12 to 15 years.
What you feed your dog is an individual choice, but working with your veterinarian and/or breeder will be the best way to determine frequency of meals as a puppy and the best adult diet to increase his longevity. Clean, fresh water should be available at all times.