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Energy dynamics during fetal to neonatal transition and the influence of perinatal energy stores on early neonatal survival
In the pig, the neonatal mortality rates are approximately 13.5% in commercial herds, which has a significant impact on the production efficiency of pork. The majority of the piglet mortality occurs within the first 3 days of life and is significantly influenced by birth weight and within-litter birth weight variability. Given that smaller piglets are the most susceptible for mortality, this illustrates a potential developmental abnormality for these piglets. Mammalian offspring experience a dramatic metabolic and environmental transition during the perinatal period. During pregnancy, the fetus is completely dependent on maternal energy substrates that are generally classified as high carbohydrate (i.e., glucose and lactate) and low fat. Under normal conditions, the mammalian uterine environment is maintained at a steady temperature and lower oxygen tension. At birth, the offspring immediately undergoes a period of starvation that ranges from minutes to hours before transitioning to exogenous ingestion of colostrum and milk that is higher in protein and fat and lower in carbohydrates. During the period of starvation, newborn offspring must utilize body reserves, primarily glycogen and fat, which were accumulated during prenatal development. In addition, the offspring is typically exposed to a sudden decrease in thermal temperature and rapid increase in oxygen tension, which influence the metabolic state of the newborn. This presentation will provide a comparative review of energy dynamics during fetal to neonatal transition in a variety of species (i.e., humans and domestic animals) and how perinatal energy stores influence early neonatal survival. Finally, this presentation will provide evidence that the Meishan piglet can serve as an effective model for survivability of small piglets.
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Keywords: Metabolism, Neonatal, Survival