I am sure that lots of NICUs worldwide use nothing but breastmilk and do well.
Please remember that many of the 600-700 gm "premies" in developing countries
are really SGA older infants, and that many die for lack of ventilators,
dopamine, etc.  The popoulations may not be comparable, as the "survivors"
have been preselected.  The USA has the highest birth & gestational age-
specific survival rates in the world.  Even though we too start BM on day 1, 2
or 3, I have a hard time believing that some of my infants would be alive, and
with optimum brain growth and neurological outcome without hyperal and
fortification of some type.
Nancy Wight MD