Does birth weight affect neonatal body weight, growth, and physiology in an animal model?

Abstract

Infant birth weight affects neuromotor and biomechanical swallowing performance in infant pig models. Preterm infants are generally born low birth weight and suffer from delayed development and neuromotor deficits. These deficits include critical life skills such as swallowing and breathing. It is unclear whether these neuromotor and biomechanical deficits are a result of low birth weight or preterm birth. In this study we ask: are preterm infants simply low birth weight infants or do preterm infants differ from term infants in weight gain and swallowing behaviors independent of birth weight? We use a validated infant pig model to show that preterm and term infants gain weight differently and that birth weight is not a strong predictor of functional deficits in preterm infant swallowing. We found that preterm infants gained weight at a faster rate than term infants and with nearly three times the variation. Additionally, we found that the number of sucks per swallow, swallow duration, and the delay of the swallows relative to the suck cycles were not impacted by birth weight. These results suggest that any correlation of developmental or swallowing deficits with reduced birth weight are likely linked to underlying physiological immaturity of the preterm infant.

Developmental factors influencing bone strength in precocial mammals: An infant pig model

“…Birthweight (i.e., mass) across the sample ranged from 0.42 to 1.7 kg. Birthweights were significantly smaller in preterm infants than in full‐term infants (Mann–Whitney U test; p = 0.001; preterm = 0.84 kg, full‐term = 1.43 kg) (see also Adjerid et al, 2021; Andersen et al, 2016).…”

“…However, birthweight had very little effect on bone strength in the infant pig sample overall. Previous studies have found that birthweight per se is also a poor predictor of functional deficits during pig development (i.e., swallowing performance; Adjerid et al, 2021). Again, it may be that accelerated intrauterine development buffers infant pigs—and perhaps other precocial infants—against the deficits predicated by low birthweight in more altricial species.…”

The effect of stiffness and hole size on nipple compression in infant suckling

“…At 7 days of age (roughly equivalent to 1–2 months postnatal in humans [Eiby et al, 2013 ]), infant pigs were recorded bottle feeding barium contrast enhanced milk replacer formula. Recordings were made using videofluoroscopy with a high‐speed camera at 100 frames per second (XC1M digital camera; Xcitex) in the lateral view (GE 9400C‐Arm, 75–85kV, 5 mA) following established feeding protocols (Adjerid et al, 2021 ; German et al, 2004 ; Mayerl, Myrla et al, 2020 ). During each recording session, piglets were bottle‐fed, first on the intermediate training nipple, then were allowed approximately 20 swallows on each of the four nipple types in randomized order.…”

“…Infant mammals have highly developed oral sensory abilities at birth, which provides specific input to the central nervous system for efficient and effective suckling. When the sensory connections involved in infant feeding are disrupted, feeding performance is compromised and infants may suffer from illness, malnourishment, and potentially life‐long developmental issues (Adjerid et al, 2021 ; Ballester et al, 2018 ; Catchpole et al, 2020 ; DeLozier et al, 2018 ; Ding et al, 2013 ; Gould et al, 2015 , 2016 , 2017 , 2020 ; Hadders‐Algra, 2018 ; Liu et al, 2018 ; Mayerl, Catchpole, et al, 2020 ; Zimmels et al, 2021 ). Yet, sensory motor integration in human infant suckling is not fully understood, making it difficult to predict how changes to sensory input affect feeding behaviors (Gould et al, 2019 ; Jean, 2001 ; Young et al, 2015 ).…”

“…suffer from illness, malnourishment, and potentially life-long developmental issues (Adjerid et al, 2021;Ballester et al, 2018;Catchpole et al, 2020;DeLozier et al, 2018;Ding et al, 2013;Gould et al, 2015Gould et al, , 2016Gould et al, , 2017Gould et al, , 2020Hadders-Algra, 2018;Liu et al, 2018;Mayerl, Catchpole, et al, 2020;Zimmels et al, 2021). Yet, sensory motor integration in human infant suckling is not fully understood, making it difficult to predict how changes to sensory input affect feeding behaviors (Gould et al, 2019;Jean, 2001;Young et al, 2015).…”