Betaine is as effective as folate at re‐synthesizing methionine for protein synthesis during moderate methionine deficiency in piglets (827.15)

Methionine is an essential amino acid that is in high demand in neonates for protein synthesis as well as for transmethylation (TM) reactions, such as creatine synthesis and DNA methylation. TM reactions produce homocysteine, which can be either converted to cysteine or re‐methylated to methionine via folate or betaine (synthesized from choline). It is unclear whether both remethylation pathways are equally important in neonates for remethylation. The objective of this study was to determine whether supplementation with folate, betaine or a combination of both (n=6) can re‐synthesize methionine for protein synthesis when dietary methionine is limiting. In piglets adapted to low‐methionine diets devoid of folate, choline and betaine, we measured 13 C‐phenylalanine oxidation pre‐ and post‐supplementation as an indicator of protein synthesis. Prior to supplementation, plasma folate (‐60%), betaine (‐95%), dimethylglycine (‐95%), choline (‐60%) and cysteine (‐45%) were all lower (p<0.05) compared to baseline with no change in homocysteine. Post‐supplementation, phenylalanine oxidation levels were ~30% lower (p<0.05) with any methyl donor supplementation with no difference among groups. This demonstrates an equal capacity for betaine and folate to remethylate methionine for protein synthesis and warrants future research on betaine in the infant diet. Grant Funding Source : Supported by Canadian Institutes of Health Research