BIRTH AND PREMATURITY INFLUENCE INTESTINAL FUNCTION IN THE NEWBORN PIG

Developmental changes in intestinal function occur in the perinatal pe riod of many species. We investigated the hypothesis that gestational age at delivery and the mode of delivery influence intestinal function . Newborn pigs (106-108 or 113-115 days gestation, term = 115 +/- 2 da ys) were either delivered by caesarean section or born vaginally follo wing induction of parturition with a prostaglandin F-2 alpha analogue. The pigs were killed at birth and used for measurements of intestinal ion transport in vitro (using Ussing chambers) or killed at 2 days of age, after being fed porcine colostrum to follow the absorption of in tact proteins into plasma. The results indicate that premature birth i s associated with increased paracellular permeability to ions. The upt ake and net absorption of chloride were higher in the term, vaginally- delivered pigs than in the remaining pigs. Among the newborn pigs, the preterm caesarean delivered pigs exhibited the lowest chloride secret ion in response to the secretagogue, theophylline. The latter pigs als o absorbed the lowest amounts of immunoglobulin G and albumin from col ostrum. In conclusion, gestational age at delivery and the mode of del ivery have significant effects on intestinal transport of ions and int act proteins. However, the observed variation in the magnitude and the direction of responses indicate that (a) prematurity and birth influe nce the transport of ions and intact proteins through independent regu latory mechanisms and (b) the absorption pathways for ions and intact proteins in the neonatal pig intestine are not closely associated. (C) 1997 Elsevier Science Inc.