Thermogenesis in Stress-susceptible Pigs: A Review

Abstract

Stress syndromes Malignant hyperthermia (MH) is a fulminant thermogenic syndrome occurring during anaesthesia in which a hypermetabolic condition stimulates muscle to the level that would be expected during intense exercise. MH occurs rarely in human subjects (Britt & Kalow 1970), but commonly in certain breeds of pig such as the Pietrain and some strains of Landrace and Poland China pigs. Such animals are often referred to as stress-susceptible because they succumb to a variety of stress factors, showing many of the signs that would be seen in MH (Sybesma & Eikelenboom 1969). The severe stress of slaughter, for example, induces a fast rate of post-mortem muscle glycolysis in such pigs: the rapid fall in pH before cooling denatures myofibrillar protein so that intracellular water is lost. This is an economically important condition referred to as pale, soft exudative (PSE) pork (Lister 1970). The association between extreme sensitivity to stress and MH in pigs has been well established. There is some evidence which suggests that individual people and families susceptible to MH may also be particularly susceptible to stress, so that there may be analogous human and porcine stress syndromes (Wingard 1974).

Brown adipocyte ATF4 activation improves thermoregulation and systemic metabolism

“…Besides cold, dietary changes also affect BAT thermogenesis through the diet-dependent thermogenesis process (Bonet et al, 2017;Kozak, 2010;Rothwell and Stock, 1979). In fact, this diet-dependent thermogenesis was also conspicuous in young pigs (without Ucp1 expression) (Dauncey and Ingram, 1979;Lucke and Hall, 1983) and humans with complete spinal cord injury (lacking sympatho-adrenal activity) (Aksnes et al, 1995). Noteworthily, this ATF4 activation in BAs can be gauged from low (under normal chow feeding) to high (under LP feeding) Reports 36, 109742, September 21, 2021 13 Article ll OPEN ACCESS in wild-type mice, suggesting that it is a physiologically relevant process that can tailor energy expenditure to changes in macronutrient composition.…”