I switched my puppy from Purina Puppy chow to Blue Buffalo puppy chow, will he be alright?

I switched from Purina Puppy to Blue Buffalo Puppy and was wondering if it'll make my puppy sick? He just ate his dinner and had a regular bowel movement after, but was it alright for me to just stop Purina and start Blue Buffalo? He is fed the recommended amount of both packages and he's a Malamute puppy.