Insights into the gut–liver–mitochondria axis in broilers: its role in metabolic health and nutritional regulation – A review

SUMMARYDuring intensive livestock and poultry production, various stress factors such as high stocking density, environmental fluctuations, and nutritional imbalance can lead to liver and intestinal dysfunction in broilers. There is a close physiological connection between these two organs. Impairment of the intestinal barrier may allow gut-derived endotoxins to enter the portal circulation, thereby triggering inflammatory responses in the liver. Conversely, abnormalities in liver function can affect gut homoeostasis through the secretion of bile and the release of inflammatory mediators. These interactions form the gut–liver axis and play a key role in regulating the body’s nutritional metabolism, immune responses, and antioxidant defences. As the central hub of energy metabolism and redox regulation, mitochondria are essential for maintaining the functionality of the gut–liver axis and constitute the gut–liver–mitochondrial axis. This axis not only influences energy production and cellular signalling but also mediates the effects of gut-derived signals on liver mitochondrial function, thereby affecting the health of the whole organism. At present, research on the gut–liver–mitochondrial axis has mainly focused on humans and mammalian models, while studies in poultry remain limited and the underlying mechanisms are largely undefined. This review systematically summarises the structural characteristics and functional relationships of the gut–liver–mitochondrial axis in broilers, with a particular focus on its roles in regulating nutritional metabolism, immune responses, and antioxidant defences. Furthermore, it explores how nutritional factors – including plant extracts, probiotics, gut microorganisms, and trace elements – can improve health and growth performance in broilers by modulating the gut–liver–mitochondrial axis. This aims to provide a reference for further investigations into the role of the gut–liver–mitochondrial axis in maintaining health in broilers.