THE EFFECT OF COMPOSITION OF MILK FEEDS ON INTESTINAL MUCOSAL PERMEABILITY, MORPOHOLOGY AND KINETICS IN THE NEWBORN

Abstract

Marked differences in intestinal mucosal permeability follow enteral feeding in the naturally and artificially fed human newborn. A guinea pig model has been used to study whether such changes are associated with morphological and kinetic changes. 17 newborn litters were fed either naturally (Nat) or a cow's milk formula (CMF) from days 1 to 5. Intestinal permeability was measured with lactulose and mannitol given as oral loads followed by five hr. urine collections. Jejunal crypt and villus morphology was studied by microdissection after bulk Feulgen staining. Mucosal proliferation was measured by a metaphase arrest technique. Comparable growth was achieved between the two groups. Intestinal permeability to lactulose fell slightly in the Nat group, but rose rapidly and remained high in the CMF (P<0.01). There were no differences in the crypt depths or villus heights in the two groups. Crypt cell production rates were higher in the CMF group on all days (P≤0.01). The newborn guinea pig may be successfully reared on a CMF. Comparable changes in intestinal lactulose permeability occur in the newborn human and guinea pig. Cow's milk may damage the mucosa causing an elevation in passive permeability and a compensatory crypt cell proliferative response.