Methionine Supplementation Benefits Lipogenesis in Goat Intramuscular Adipocytes, Likely by Inhibiting the Expression of SLC5A5

Intramuscular fat (IMF) is a crucial indicator of meat quality. Recent studies increasingly suggest that methionine (Met) plays a role in fat accumulation. However, the mechanism by which Met affects the proliferation and differentiation of intramuscular adipocytes remains unclear. In this study, goat intramuscular adipocytes were cultured in basal complete medium supplemented with Met at 0, 50, 100, 200, 400, and 800 μM. This study demonstrates a quadratic relationship between the level of Met supplementation and cellular proliferation and differentiation, with an optimal effect observed at 100 μM Met. The results of RNA-seq analysis demonstrated that supplementation with Met led to the downregulation of genes involved in lipid metabolism, including the genes <i>PER2</i>, <i>PRKG1</i>, and <i>SLC5A5</i>. Furthermore, we found that overexpression of <i>SLC5A5</i> inhibits adipogenic differentiation in goat intramuscular adipocytes, while Met supplementation reversed this inhibitory effect. In addition, silencing <i>SLC5A5</i> significantly promoted adipogenic differentiation, whilst Met supplementation further enhanced this promotion effect. In conclusion, this study indicates that Met supplementation of basal complete medium benefits adipogenic differentiation of goat intramuscular adipocytes, likely by inhibiting the expression of <i>SLC5A5</i>. This research provides a foundation for improving goat meat quality.