Betaine affects abdominal flare fat metabolism via regulating m6A RNA methylation in finishing pigs fed a low-energy diet

This study was conducted to investigate the effects of betaine on lipid metabolism and m6A RNA methylation in finishing pigs fed a low-energy diet. The results showed that betaine significantly enhanced serum concentration of triglyceride and reduced the relative weight of flare fat (P < 0.05) in pigs fed a low-energy diet, as well as, changed mRNA or protein expression of genes related to lipogenesis and lipolysis (P < 0.05). Betaine reversed the reduction in mRNA or protein abundances of YTH N6-methyladenosine RNA-binding protein 1 (YTHDF1) and YTHDF2 caused by low-energy diet, and increased the levels of m6A RNA methylation and the expressions of methyltransferase-like 3 (METTL3), METTL14 (P < 0.05). Collectively, betaine decreased the flare fat content of finishing pigs exposed to low-energy diet by reducing lipogenesis and increasing lipolysis, and this phenotypic change was attributed to the elevation of m6A RNA methylation level by betaine.