Fatty liver haemorrhagic syndrome (FLHS) is a nutritionally induced metabolic disorder predominantly affecting laying hens, characterized by abnormal lipid deposition within hepatocytes and abdominal adipose tissue. Hepatic hemorrhages and liver function disorders are primary mortality drivers in caged commercial laying hens, particularly within intensive confinement systems where metabolic stressors are prevalent. They inflict substantial economic damage on the poultry sector through dual pathways: direct bird mortality and/or reduced egg output in infected flocks. Its pathogenesis is related to a variety of factors, including improper proportion of nutrients, lack of exercise, and the influence of estrogen. Bile acids, which are cholesterol-derived compounds synthesized in the liver, are crucial for fat metabolism. At present, a few studies on the direct relationship between bile acids and fatty liver syndrome are quite popular. Meanwhile, certain studies are also available indicating that the gut microbiota is closely related to the incidence of fatty liver. However, bile acids and gut microorganisms have an interactive relationship with each other. Therefore, this article aims to explore the interaction among bile acids, gut microbiota and fatty liver in laying hens, and to better understand the mechanism of the intestinal-liver axis research, in order to develop effective prevention and treatment methods for fatty liver in laying hens.

To Cite This Article: Cheng S, Liu X, Cheng S, Zhang S, liu P, Zhuang Y and Hu G, 2025. The research mechanism of the gut-liver axis in non-alcoholic fatty liver disease. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2025.300