Breastmilk

Should have asked my sons pediatrician when I was in there but I forgot so I'll see if you ladies know, 
So I pump milk but mainly just put my son on my boob, but in the middle of the night it's nice to just use the bottles.. anyways my question is, how many oz should I give my son? He's 6 days old, 7 days old tomorrow and he's pretty small. 5lbs 12oz