Your puppy should be on a "Puppy Formula" of whatever food you choose.
I feed my Cavaliers "Wellness Super 5 Mix". I think that comes in a puppy formula as well. I would read the ingredients on a food such as that, or one similar and find the puppy formula, which they should be on for the first year!
If what you are feeding is giving your puppy excessive gas, you may wish to switch. However, I would also caution against switching too often as that is very hard on a pup's tummy. What did your Breeder suggest you feed? I stuck with the food from Oliver's Breeder for the first several years of his life, which at the time was a medium rated food. Once he became ill and started gaining a lot of weight, I then searched for a better quality food, and he is on the adult "light" formula of that food.
Please go to our "Health Section" as there are many different types of discussions on feeding in there. Two of our members with Cavaliers feed nothing but Raw, that they do themselves. There is a thread on that in the Health Section called something like "I met a Pig's Foot today". I'm paraphrasing.
Avoid any food that has "meat by products", "grains", "corn meal"....you wish to look for foods that list MEAT as the first ingredient and only certain whole grains. Orijen is considered one of the top foods in the world and is made here in Canada, but some people are now saying that it's a little too high in protein.
Many of us have used http://www.dogfoodanalysis.com
to look at the various feeds available, but I've recently been told that site may be slightly out of date. However, it will give you a broad overview and rate the various foods to give you an idea of side by side comparisons.