Abstract
Animal welfare is one of the core concerns in the field of animal science, with behavior serving as a direct reflection of emotional state and health, and thus a key indicator for welfare assessment. With the widespread adoption of intensive farming systems, abnormal behaviors in pigs have become a prominent marker of compromised welfare. In the past few years, the role of gut microbes in the regulation of animal behavior has received increasing attention. This review summarizes the strong relationship between pig behavior and welfare, and focuses on the emerging research linking gut microbiota to behavioral expression in pigs. Furthermore, it outlines the mechanisms by which the microbiota modulates behavior through the microbiota-gut-brain axis (MGBA), including immune, endocrine, and neural pathways. Additionally, the potential of microbiota-targeted interventions to improve pig welfare, including probiotics and prebiotics, will be evaluated. As a critical bridge connecting physiology and psychology, the gut microbiota shows significant promise for advancing welfare regulation in pigs.