Transitional feeding in developing pigs: Effects of food texture modification on liquid swallowing behavior and epiglottic movements

Food texture modifications facilitate the transition from suckling to chewing. We examined drinking and liquid swallowing in 2 groups of pigs: one group directly transitioned from liquids to solids (DT) and the other transitioned progressively (PT) from liquids to soft foods then to solids. Our study reports the typical outcome of maturation of oropharyngeal physiology in both groups with similarities in the behavioral aspects of liquid swallowing (swallows occur during ingestion cycles, similar cycle frequency). However, compared to DT pigs, PT pigs used fewer gape cycles and less time between swallows and initiated the swallow later in the gape cycle, which are characteristics of swallow in younger pigs. Swallows in PT pigs were also typically faster with shorter epiglottal descent duration to reach laryngeal vestibule closure (LVC) quicker, thus increasing LVC duration significantly relative to swallow duration. Furthermore, throughout the study, epiglottal descent duration decreased in PT pigs but increased in DT pigs, emphasizing how each transition strategy altered the maturation of a key component of the swallow. Our results expand our understanding of liquid swallowing behavior in mammals and showcase how food-texture modification during a critical period of development can impact the maturation of swallow physiology.