**Di**ff**erential Metabolomics Profiles Identified by CE-TOFMS between High and Low Intramuscular Fat Amount in Fattening Pigs**

**Masaaki Taniguchi 1,\*, Aisaku Arakawa 1, Motohide Nishio 1, Toshihiro Okamura 1, Chika Ohnishi 2, Kouen Kadowaki 3, Kimiko Kohira 4, Fumika Homma 4, Kazunori Matsumoto 4 and Kazuo Ishii 1**


Received: 25 June 2020; Accepted: 5 August 2020; Published: 7 August 2020

**Abstract:** The amount of intramuscular fat (IMF) present in the loin eye area is one of the most important characteristics of high-quality pork. IMF measurements are currently impractical without a labor-intensive process. Metabolomic profiling could be used as an IMF indicator to avoid this process; however, no studies have investigated their use during the fattening period of pigs. This study examined the metabolite profiles in the plasma of two groups of pigs derived from the same Duroc genetic line and fed the same diet. Five plasma samples were collected from each individual the day before slaughter. Capillary electrophoresis-time of flight mass spectrometry (CE-TOFMS) was used to analyze the purified plasma from each sample. Principle component analysis (PCA) and partial least squares (PLS) were used to find the semi-quantitative values of the compounds. The results indicate that branched-chain amino acids are significantly associated with high IMF content, while amino acids are associated with low IMF content. These differences were validated using the quantification analyses by high-performance liquid chromatograph, which supported our results. These results sugges<sup>t</sup> that the concentration of branched-chain amino acids in plasma could be an indicative biomarker for the IMF content in the loin eye area.

**Keywords:** biomarker; CE-TOFMS; intramuscular fat; meat quality; metabolomics; porcine
