Abstract

To investigate the effects of dietary leucine supplementation on muscle fiber type transformation in weaning piglets, 54 21-day-old male DLY (Duroc × Landrace × Yorkshire) weaned piglets were randomly divided into control, 0.25% and 0.5% leucine groups. The experiment lasted for 42 d. The results showed that dietary supplementation of 0.25% leucine significantly increased the protein expressions of slow MyHC, myoglobin and Troponin I-SS and the mRNA expressions of MyHC I, MyHC IIa, Tnni1, Tnnc1, Tnnt1 and myoglobin, while decreased the protein level of fast MyHC and the mRNA level of MyHC IIb in longissimus dorsi (LD) muscle. Furthermore, 0.25% leucine significantly increased succinic dehydrogenase (SDH) activity and decreased lactate dehydrogenase (LDH) activity. In addition, our data found that 0.25% leucine significantly increased serum adiponectin (AdipoQ) concentration, and the protein levels of AdipoQ, adiponectin receptor 1 (AdipoR1), phosphorylated AMP-activated protein kinase (p-AMPK) and PPAR-γ coactivator-1α (PGC-1α) and the mRNA levels of AdipoQ, AdipoR1 and AMPKα2. Together, our findings indicate that leucine promotes porcine skeletal muscle fiber type transformation from fast-twitch to slow-twitch, and the effect may be mediated by AdipoQ-AMPK-PGC-1α signaling pathway.

摘要

为研究日粮添加亮氨酸对断奶仔猪肌纤维类型转化的影响，将 54 头 21 日龄雄性 DLY (Duroc × Landrace × Yorkshire) 断奶仔猪随机分为对照组、0.25% 和 0.5% 亮氨酸组。实验持续42 d。结果表明，日粮中添加0.25%亮氨酸显着增加慢速MyHC、肌红蛋白和肌钙蛋白I-SS的蛋白表达以及MyHC I、MyHC IIa、Tnni1、Tnnc1、Tnnt1和肌红蛋白的mRNA表达，同时降低了慢速MyHC、肌红蛋白和肌钙蛋白I-SS的蛋白表达。背最长肌快速 MyHC 和MyHC IIb的mRNA 水平(LD) 肌肉。此外，0.25% 的亮氨酸显着增加了琥珀酸脱氢酶 (SDH) 的活性并降低了乳酸脱氢酶 (LDH) 的活性。此外，我们的数据发现，0.25% 亮氨酸显着增加血清脂联素 (AdipoQ) 浓度，以及 AdipoQ、脂联素受体 1 (AdipoR1)、磷酸化 AMP 活化蛋白激酶 (p-AMPK) 和 PPAR-γ 共激活剂的蛋白质水平- 1α (PGC-1α) 和AdipoQ、AdipoR1和AMPKα2的 mRNA 水平。总之，我们的研究结果表明，亮氨酸促进猪骨骼肌纤维类型从快肌纤维向慢肌肌纤维类型的转变，这种作用可能是由 AdipoQ-AMPK-PGC-1α 信号通路介导的。