Physical activity-induced myokine responses in major mammalian farm animal species: a mini-review.

Physical activity, including related concepts such as locomotion, movement, and exercise, is a fundamental behavior in humans and animals and contributes to physical and mental health. Although physical activity is essential for maintaining skeletal muscle function, farm animals are often kept under housing conditions with limited space and restricted opportunities for locomotion. Skeletal muscle secretes myokines that contribute to interorgan crosstalk; however, the relationship between physical activity and myokine-related responses in farm animals remains poorly understood. To summarize the current state of knowledge, we conducted a systematic literature search in PubMed, Scopus, and Web of Science in April 2026, focusing on studies addressing physical activity and myokine-related outcomes in major mammalian farm animal species. In total, 35 studies were identified. These studies examined several myokines, including interleukin-6 (IL6), fibronectin type III domain-containing protein 5 (FNDC5/irisin), brain-derived neurotrophic factor (BDNF), myostatin (MSTN), and insulin-like growth factor 1 (IGF1). The included studies showed substantial heterogeneity in experimental design, activity assessment, biological sample type, and the type, intensity, and quantification of activity. Overall, the current literature provides preliminary but fragmented evidence that physical activity is associated with myokine-related responses. However, a major limitation is the lack of standardized and objective methods for quantifying physical activity in farm animals, particularly within voluntary, self-directed activity paradigms. Conceptually, farm-relevant studies combining objective activity monitoring with skeletal muscle and systemic myokine analyses are required to clarify how physical activity contributes to muscle biology, performance, health, and welfare in livestock species.