Do you want a specific vitamin, for a specific cause? The same vitimins that work on other dogs work on APBTs. Go to your local pet store and ask for an everyday vitimin or supplement. I know you have pups so you could consider a product that is balanced for pups and helps in proper growth and immune.
I use K-Zyme vitamins for all of my dogs. It helps with the digestion of their food, shedding, makes their coats very shiny, and is great for their overall health. They get one tablet a day and they think it is a treat.