Birth and Prematurity Influence Intestinal Function in the Newborn Pig

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Developmental changes in intestinal function occur in the perinatal period 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 days) were either delivered by caesarean section or born vaginally following induction of parturition with a prostaglandin F 2 α 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 intact proteins into plasma. The results indicate that premature birth is associated with increased paracellular permeability to ions. The uptake 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 secretion in response to the secretagogue, theophylline. The latter pigs also absorbed the lowest amounts of immunoglobulin G and albumin from colostrum. In conclusion, gestational age at delivery and the mode of delivery have significant effects on intestinal transport of ions and intact proteins. However, the observed variation in the magnitude and the direction of responses indicate that (a) prematurity and birth influence the transport of ions and intact proteins through independent regulatory mechanisms and (b) the absorption pathways for ions and intact proteins in the neonatal pig intestine are not closely associated.