[theBCnut]

No suggestions on food, but it would take more dehydration than that to show up with high BUN. If you really want to be sure, you can ask your vet to give your dog sub q fluids and then wait around a while before he takes blood, but I personally wouldn’t bother.

If you are up to the task of making homemade food, there are companies that will formulate a recipe for you. But they will want to go through your vet.