Chiral derivatization LC-TOF/MS analysis reveals presence of D-amino acids in bovine skeletal muscle tissue and the cultured cells

In mammalian tissues, D -amino acids (AAs) play important roles in the physiological functions of immunity and the brain; however, little is known about D -AAs in the skeletal muscle. Here we investigated the composition and content of D / L -AAs in trapezius muscle tissue and the cultured cells of Japanese Black (JBL) and Japanese Brown (JBR) cows at slaughter and seven days postmortem, using chiral derivatization LC-TOF/MS method. Most of the L- AAs were distributed across almost all samples examined, with differences observed between AAs. Among D -AAs, D- serine ( D- Ser) and D- aspartate ( D- Asp) were detected in all samples; D -Asp content in JBL cells was higher than that in the muscle tissues of both cattle and JBR cells. D -Ser content in both muscle tissue and cell samples was higher in JBL than in JBR. D- threonine ( D- Thr) was detected in the muscle tissue, but not in the cell cultures that contained D -Asp and D -Ser. This is the first study to demonstrate the presence of D- AAs in bovine skeletal muscle, particularly D -Thr in farm animal tissues. These findings contribute to understanding depth in bovine skeletal muscle physiology and beef quality. • D -amino acids in bovine muscles have been investigated for the first time. • An original chiral derivatization LC-TOF/MS method efficiently distinguished D / L -AAs. • D -Ser, D -Asp, and D -Thr were detected in the live bovine muscle and aged beef. • D -Thr has been detected for the first time in farm animal tissue.