ACTA1 gene regulation in livestock: A multidimensional review on muscle development, meat quality, and genetic applications.

The skeletal muscle α-actin gene (ACTA1) plays a pivotal role in muscle contraction, structural integrity, and overall development of skeletal muscle tissue in livestock. This review explores the complex regulatory mechanisms of ACTA1 expression and its direct impact on meat quality, animal performance, and production efficiency. Nutritional inputs, environmental stressors, hormonal signaling, and genetic factors collectively influence ACTA1 activity at the transcriptional, translational, and epigenetic levels. High-protein diets rich in branched-chain amino acids, particularly leucine, stimulate the mechanistic target of rapamycin pathway and enhance ACTA1-mediated muscle growth. Similarly, micronutrients such as zinc and selenium function as antioxidants, stabilizing ACTA1 expression under oxidative stress conditions. The review also delves into the role of ACTA1 polymorphisms in modulating muscle fiber type composition, particularly the balance between type I and type II fibers, which significantly affects meat tenderness, fat content, and endurance capacity. Genome-wide association studies, marker-assisted selection (MAS), and clustered regularly interspaced short palindromic repeats-associated protein 9-based genome editing provide promising avenues for optimizing ACTA1 expression in livestock breeding programs. Moreover, ACTA1 dysregulation or mutation is linked to several congenital myopathies, underscoring its diagnostic and therapeutic relevance in veterinary pathology. Biotechnological interventions targeting ACTA1 expression present immense potential for improving muscle mass, carcass traits, and feed efficiency, thereby supporting global food security. Future strategies combining nutrigenomics, precision livestock farming, and artificial intelligence could enable tailored breeding and management approaches for sustainable meat production. Ethical and environmental considerations will be critical as gene editing technologies move toward wider application. In summary, ACTA1 represents a cornerstone of muscle physiology in livestock, and its integrative regulation across nutrition, genetics, and environment offers vast potential for advancing meat science, animal health, and agricultural productivity.