A good dog food will contain meat, vegetables, grains, and fruits. The best dog foods contain high-quality versions of ingredients that are good fro your dog's digestive system.
We are currently using Taste of the Wild Ancient Prairie with Ancient Grains. It is a high protein diet suited for dogs who will be using a lot of energy, i.e. pregnant, nursing, growing.
This is an all ages dog food, which means you can use the same food throughout the life of your dog. They have many different formulas from grain free to grain inclusive. They also offer many different flavors. Check them out then talk to your vet about what is best for your puppy. Keep in mind not all dogs need the same amount of protein and fat. Another formula might be better suited for your dog.