Some aspects of perinatal maturation and adaptation.

The research focuses on studying physical maturation and adaptation processes in newborn mammals. It assesses the constraints on thermogenesis (heat production), highlighting the importance of carbohydrate supply vs. reserves, and the role of colostrum in the process. The study also delves into the development of the gastrointestinal system pre and post birth, and the impact of growth factors present in milk, especially colostrum, on this process.

Thermogenesis and Carbohydrate Utilisation

• The transition from intrauterine to external environment post-birth presents significant physiological challenges. One important aspect of this adaptation is thermogenesis or heat production.
• The study elucidates the relation between the body’s fuel reserves and its ability to generate heat. The role of carbohydrates, notably glycogen (a form of stored carbohydrate), is emphasised.
• Carbohydrates are identified as a major limiting factor in the newborn’s thermogenic process. It becomes critical that the newborn can access and utilise its stored glycogen reserves in light of a limited external supply from colostrum (a type of milk produced at the end of pregnancy).
• Observations from multiple species, including horses, indicate that colostrum does not provide adequate levels of lactose (a carbohydrate) to meet the entire carbohydrate needs of newborns, especially within the first 24 hours post-birth. Hence the reliance on internal glycogen reserves.

Growth and Maturation of the Gastrointestinal System

• Besides the thermogenic function, glycogen reserves also contribute to general metabolism and growth, including that of the gastrointestinal system.
• Both prenatal and postnatal development of the animal’s stomach and intestines are scrutinised. The research highlights a disproportionately rapid growth of these organs in contrast to the rest of the body during the first three days post-birth.
• The study explores the possible contribution of milk-derived growth factors such as epidermal growth factor (EGF) and insulin-like growth factor (IGF) to this accelerated gastrointestinal growth. The high levels of these factors present in colostrum are considered critical stimulators of gastrointestinal growth and maturation immediately after birth.