Great Danes

About a month ago my husband brought home this little puppy he found walking down the middle of a very busy highway. We took him to the vet, first thing she said was "He looks like he's a dane" and that he was much younger than we had thought. Going by his teeth, he'd now be around 13 weeks. He looks a LOT like GD puppy pictures i've been googling and he's gotten so much bigger in just these past few weeks. My concern is his diet, I've been reading how it's very important in these early years. Any suggestions on how much, how often and type of food?

Thanks for your fast reply! I've been feeding him IAMS Healthy Puppy since we've gotten him. We're living in Sicily and the choice in this area are pretty limited. I'll google and see which foods are recommended and see what I can either get here or have shipped to me.