Background and aims Preterm infants exhibit delayed neonatal arousal and impaired motor function. Impaired neuromuscular development, probably interacting with gut and metabolic dysfunctions, may explain this. Using preterm pigs as models, we hypothesised that early initiation of enteral feeding stimulates both gut growth and neonatal arousal and physical activity.
Methods Experiment 1: Caesarean-delivered preterm and term pigs were fed parenteral nutrition (PN) or PN plus enteral bovine colostrum (BC) for five days. Other preterm pigs were fed PN with or without BC or formula for five days (Experiment 2), or increasing doses of BC, formula or human milk (HM) for 10 days (Experiment 3). Daily energy intake was matched among the groups in each experiment and home cage activity (HCA) was recorded by continuous camera surveillance.
Results Prematurity at birth delayed eye lid opening, first stand and walk, and reduced relative intestinal weight and HCA (Experiment 1, all p < 0.01). Supplementing PN with BC or formula increased intestinal weight and HCA values (Experiment 2, p < 0.05). Enteral BC feeding increased HCA and intestinal weights, relative to formula or HM (Experiment 3, p < 0.05).
Conclusions Prematurity decreased physical activity and relative gut weight within the first week after birth. Small volumes of enteral feeds increased the activity. This may result from general metabolic effects of enteral feeding but could also reflect a direct diet-dependent, gut-neuromuscular maturation in preterm neonates fed enterally. The results support the importance of early enteral feeding of preterm infants with adequate amounts of an optimal diet.