[Nancy1999]

There's an "optimum" amount of nutrition that organisms thrive on, but they will do okay without this optimum level. Dog foods are made specially to meet the optimum level, not basic minimum requirements. Puppy foods generally have higher fat and higher protein than adult foods because they don't have any excess fat on them and they are growing and need lots of calories. Will your pup do okay on adult food, probably, but I wouldn't do it, I'd wait till at least 6 months before I feed adult food. If you give them both puppy food, you're adult might put on a little weight. I'd probably give both the puppy food because the puppy is the one that has great nutrition needs at this time.

By the way, it's generally advisable to get a vet check within days of bringing home a new puppy, hopefully they are both doing well.