In addition to an increased protein and fat content, a puppy also has an increased need for many other nutrients: He needs more calcium and less phosphorus than an adult dog, and the need for vitamins A, D3 and E is also significantly higher.
Whether supplementation is necessary for this depends primarily on the ingredients used in the Barf menu: For example, for a meal with a lot of bones or cartilage, hardly any calcium additives are necessary; muscle meat is mainly used.
Attention: Many minerals and fat-soluble vitamins cannot be excreted by the body! An oversupply through too many additives can then be at least as harmful as malnutrition.