Ishida Aiko, Ashihara Akane, Nakashima Kazuki, Katsumata Masaya
Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
School of Veterinary Science, Azabu University, Sagamihara, Kanagawa, Japan.
Anim Sci J. 2023 Jan-Dec;94(1):e13861. doi: 10.1111/asj.13861.
We investigated the effects of a low-protein diet and feed restriction on the mRNA expression of cationic amino acid transporters (CATs) in the longissimus dorsi (LD), rhomboideus (RH), and biceps femoris (BF) muscles of pigs. Eighteen piglets were divided into three groups: a control (CP21%), low-protein diet (LP, CP16%), and feed-restricted diet (FR, CP21%, 76% feed intake of control pigs) groups. The expression levels of CAT-1 in the LD and BF muscles of LP pigs were higher than that of control pigs, whereas that of FR pigs showed no difference. The CAT-2A expression levels in the RH muscle of FR pigs were higher than that of control pigs. The free lysine concentrations in all muscles of LP and FR pigs were lower than that of control pigs. To examine the factors that affect CATs mRNA expression, we evaluated the effects of lysine, arginine, insulin-like growth factor-I, and dexamethasone on the expression of CATs in C2C12 myotubes. CAT-1 expression levels increased in lysine and/or arginine deprivation. We show that CAT-1 and CAT-2A expression levels in skeletal muscles differ in response to dietary treatments and CAT-1 expression in skeletal muscles appears to increase in response to low free lysine concentrations.
我们研究了低蛋白饮食和限饲对猪背最长肌（LD）、菱形肌（RH）和股二头肌（BF）中阳离子氨基酸转运体（CATs）mRNA表达的影响。18头仔猪被分为三组：对照组（CP21%）、低蛋白饮食组（LP，CP16%）和限饲组（FR，CP21%，采食量为对照猪的76%）。LP组猪的LD和BF肌肉中CAT-1的表达水平高于对照组猪，而FR组猪的CAT-1表达水平无差异。FR组猪的RH肌肉中CAT-2A的表达水平高于对照组猪。LP组和FR组猪所有肌肉中的游离赖氨酸浓度均低于对照组猪。为了研究影响CATs mRNA表达的因素，我们评估了赖氨酸、精氨酸、胰岛素样生长因子-I和地塞米松对C2C12肌管中CATs表达的影响。在赖氨酸和/或精氨酸缺乏时，CAT-1表达水平升高。我们发现，骨骼肌中CAT-1和CAT-2A的表达水平因饮食处理而有所不同，骨骼肌中CAT-1的表达似乎会因游离赖氨酸浓度降低而增加。
