Effects of dietary l‐theanine supplementation on pork quality and muscle fiber type transformation in finishing pigs

Abstract Background This experiment aimed to investigate effects of dietary l ‐theanine supplementation on pork quality and muscle fiber type transformation in finishing pigs. In a 30‐day experiment, 18 healthy Duroc × Landrace × Yorkshire (DLY) pigs with an average body weight of 86.03 ± 0.83 kg were randomly divided into three groups (a basal diet or a basal diet supplemented with 500 and 1000 ppm l ‐theanine, respectively), with six duplicates and one pig per replicate. Results The results showed that dietary 1000 ppm l ‐theanine supplementation significantly reduced ( P < 0.05) b * 24 h and drip loss. Dietary 1000 ppm l ‐theanine supplementation significantly increased ( P < 0.05) slow myosin heavy chain (MyHC) protein expression and the percentage of slow‐twitch fibers, as well as significantly decreased ( P < 0.05) fast MyHC protein expression and the percentage of fast‐twitch fibers, accompanied by an increase in succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) activities and a decrease in lactate dehydrogenase (LDH) activity. In addition, the adenosine monophosphate (AMP)‐activated protein kinase (AMPK) signaling pathway was activated by l ‐theanine. Conclusion Together, this study demonstrated for the first time that dietary supplementation of 1000 ppm l ‐theanine can improve pork color and drip loss and promote muscle fiber type transformation from fast‐twitch to slow‐twitch in finishing pigs. © 2022 Society of Chemical Industry.