Mutton is an important source of meat nutrition in the world, but the mutton production performance of goats is low and the individual is small, because there is a lack of good meat goat breeds. Skeletal muscle is closely related to the meat yield of livestock, accounting for about 40 % of body weight [1], and myoblast differentiation is a key link in skeletal muscle development, which directly affects the meat production efficiency [2]. This process is accompanied by changes in the way energy metabolism, which is transformed from glycolysis metabolism to oxidative metabolism [3]. Therefore, it is important to study the interaction between energy metabolism and myoblast differentiation to improve the meat production performance of goat.

Fat acid oxidation (FAO) is a type of oxidative metabolism that is more efficient in generating energy [4]. The activity level of FAO determines the metabolic rate of the organism. Studies on energy metabolism during differentiation, including a chicken muscle antibody array screening and biological function analysis, showed that processes and compound metabolism related to energy production play a significant role in myogenesis [5]. LDHA, associated with energy metabolism and ATP production, enhance myoblast differentiation by boosting the NADH cycle [6]. Additionally, studies have found that fat acid metabolism plays a regulatory role by inhibiting specific cell differentiation during the endodermal differentiation stage of embryonic development [7]. Skeletal muscle development begins in the paraxial mesoderm [8]. Therefore, it is of great significance to explore the role of FAO in the myoblast differentiation. However, the mechanism by which FAO regulates myoblast differentiation is unclear.

Acetyl-CoA Carboxylase 2(ACC2) is widely recognized as a rate-limiting enzyme in the regulation of FAO. Located on the outer mitochondrial membrane, ACC2 generates malonyl-CoA [9], inhibiting the transport of acyl carnitines to mitochondria via CPT1A, thereby regulating fat acid oxidation. Further research indicates that ACC2, through its critical role in cellular metabolism, may also indirectly affect the signaling pathways of muscle cells, thus participating in regulating muscle fiber type conversion and adaptive changes [10]. For example, changes in ACC2 activity can affect the activity of AMPK within muscle cells [11], regulating the transition of muscle fibers to more endurance types and muscle fiber hypertrophy [[12], [13], [14], [15]]. The fetal stage is critical for muscle fiber formation, with counts stabilizing post-birth. Specifically, muscle fibers increase rapidly between days 40 and 100 of pregnancy. This study identified differentially expressed ACC2 genes by analyzing RNA sequences from the longissimus dorsi of lambs at day one and fetuses at day 75 of pregnancy. This suggests that ACC2 plays a significant role in the growth and development of skeletal muscle, but the role of ACC2 in influencing goat myoblast differentiation and the mechanism by FAO remains to be elucidated.

To address this critical knowledge gap, we investigate the role of ACC2 in the differentiation of goat myoblasts and investigate its potential molecular mechanism. We demonstrate that interference with ACC2 promotes myoblast differentiation by increasing FAO. In addition, we found that ACC2 is dependent on the AMPK/ACC2 pathway, which enhances energy metabolism by promoting mitochondrial fatty acid uptake, thus promoting myoblast differentiation. This study establishes the groundwork for goat breeding research by utilizing genetic markers, associated with FAO and efficient muscle differentiation to breed genetically superior livestock with higher meat yield and quality.