Breast-milk-enhanced intestinal and somatic growth in neonatal rats.

Ten rat pups fed pooled rat milk and 9 pups fed artificial formula had significantly heavier stomachs and intestines that contained more DNA and RNA by 40 h of age than 12 pups sacrificed at birth. Breast-milk-fed animals had significantly heavier intestines, livers and kidneys than animals fed artificial formula. The intestines of pups fed breast milk contained more DNA and RNA with a lower RNA:DNA ratio than the intestines of pups fed artificial formula. Hence, when caloric intake and mode of feeding are controlled, natural milk enhances neonatal intestinal growth more than artificial formula.