Invited Review: The preterm pig as a model in pediatric gastroenterology.

At birth, the newborn mammal under-goes a transition from a sterile uterine environment with a constant nutrient supply, to a microbe-rich envi-ronment with intermittent oral intake of complex milk nutrients via the gastrointestinal tract (GIT). These functional challenges partly explain the relatively high morbidity and mortality of neonates. Preterm birth interrupts prenatal organ maturation, including that of the GIT, and increases disease risk. Exemplary is nec-rotizing enterocolitis (NEC), which is associated close-ly with GIT immaturity, enteral feeding, and bacterial colonization. Infants with NEC may require resection of the necrotic parts of the intestine, leading to short bowel syndrome (SBS), characterized by reduced digestive capacity, fluid loss, and dependency on par-enteral nutrition. This review presents the preterm pig as a translational model in pediatric gastroenterology that has provided new insights into important pediat- ric diseases such as NEC and SBS. We describe pro-tocols for delivery, care, and handling of preterm pigs, and show how the immature GIT responds to delivery method and different nutritional and therapeutic inter-ventions. The preterm pig may also provide a sensitive model for postnatal adaptation of weak term piglets showing high mortality. Attributes of the preterm pig model include close similarities with pretenn infants in body size, organ development, and many clinical features, thereby providing a translational advantage relative to rodent models of GIT immaturity. On the other hand, the need for a sow surgical facility, a pig-let intensive care unit, and clinically trained personnel may limit widespread use of preterm pigs. Studies on organ adaptation in preterm pigs help to identify the physiological basis of neonatal survival for hypersensi-tive newborns and aid in defining the optimal diet and rearing conditions during the critical neonatal period. [ABSTRACT FROM AUTHOR]