Dietary betaine regulates the synthesis of fatty acids through mTOR signaling in the muscle of zebrafish

Abstract

• Betaine decreases the gene expression and activities of ACL, ACC, and FAS. • Betaine regulates the synthesis and composition of fatty acids in zebrafish. • Betaine induces mTOR signaling in the muscle of zebrafish. • Betaine inhibits the synthesis of fatty acids via mTOR signaling. Betaine has three active methyl groups, which determine its unique function in the metabolism of animals. In this study, the mechanism that betaine regulates the synthesis of fatty acids via mTOR signaling was investigated in zebrafish. It was found that betaine induced the protein expression of mTOR, P-4EBP1, and P-S6, but inhibited the gene expression of GSK-3β, ACC, ACL, and FAS in the muscle of zebrafish. In addition, betaine decreased the content of NEFA and TG as well as the activities of ACC, ACL, and FAS. The total content of PUFA was elevated, but the total content of SFA was decreased by betaine treatments. Moreover, the interference of GSK-3β gene induced mTOR signaling but decreased the gene expression of ACL, ACC, and FAS in muscle. In all, betaine could induce mTOR signaling, which may further participate in regulating the synthesis of fatty acids in the muscle of zebrafish.