Changes in the coordination between respiration and swallowing from suckling through weaning

All mammals undergo weaning from milk to solid food. This process requires substantial changes to mammalian oropharyngeal function. The coordination of swallowing and respiration is a crucial component of maintaining airway function throughout feeding and matures over infant development. However, how this coordination is affected by weaning is unknown. In this study we ask how changes in posture, neural maturation, and food properties associated with weaning affect coordination of respiration and swallowing in a validated infant pig model. We recorded 7 piglets feeding before and during weaning age with liquid milk in a bottle, in a bowl, and solid feed in a bowl. Using videofluoroscopy synchronized with respiration we found 1) the delay in the onset of inspiration after swallowing does not change with head position; 2) the delay is different between solid food and bowl drinking at the same age; and 3) the delay increases over time when bottle feeding, suggesting a maturational effect. Significant changes in aerodigestive coordination occur prior to and post weaning, resulting in distinctive patterns for liquid and solid food. The interplay of maturational timelines of oropharyngeal function at weaning may serve as a locus for behavioral and life history plasticity.