Characterization of Mitochondrial Content and Respiratory Capacities of Broiler Chicken Skeletal Muscles with Different Muscle Fiber Compositions
Characterization of Mitochondrial Content and Respiratory Capacities of Broiler Chicken Skeletal Muscles with Different Muscle Fiber Compositions
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DOI：
10.2141/jpsa.0170141
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发表时间：
2018-07-01
影响因子：
1.5
通讯作者：
Kikusato, Motoi
中科院分区：
文献类型：
--
作者：
Hakamata, Yuki;Watanabe, Kouichi;Kikusato, Motoi
线粒体含量被认为是一个有用的功能，以区分肌肉纤维类型的能量代谢方面的骨骼肌。越来越多的证据表明，特定的线粒体生物能表型存在于代谢不同的肌纤维。一些研究已经研究了家禽骨骼肌的能量特性，但是，没有关于选择性饲养的肉鸡肌肉生物能量学的信息。在这项研究中，我们的目的是表征完全由I型（氧化）（M pubo-ischio-femoralis pars medialis），HA型（糖酵解/氧化）（M pubo-ischio-femoralis pars lateralis）和IIB型（糖酵解）（M pectoralis）肌纤维组成的鸡骨骼肌的线粒体内容物和功能。柠檬酸合酶（CS）的活性是最高的IIA型肌肉组织和分离的线粒体，在测试的肌肉组织。尽管IIB型和I型肌肉之间的线粒体CS活性没有差异，但后者的组织CS活性显着更高。组织化学染色的NADH四唑还原酶和肌组织线粒体CS活性的比例表明，I型，HA型，IIB型肌纤维类型显示线粒体含量下降。从I型肌肉的线粒体表现出较高的耦合呼吸速率诱导丙酮酸/苹果酸，棕榈酰辅酶A/苹果酸，棕榈酰-肉毒碱，作为呼吸底物，比IIB型肌肉线粒体，而IIA型肌肉的线粒体对这些底物的反应是可比的线粒体从I型肌肉。HA型肌线粒体中肉毒碱棕榈酰转移酶-2水平最高，这可能是这些线粒体中较高的脂肪酸氧化的原因。结果表明，线粒体丰度是区分不同类型鸡骨骼肌代谢特征的特征之一。此外，该研究表明，IIA型肌肉线粒体可能具有不同的代谢能力。
Mitochondrial content is regarded a useful feature to distinguish muscle-fiber types in terms of energy metabolism in skeletal muscles. Increasing evidence suggests that specific mitochondrial bioenergetic phenotypes exist in metabolically different muscle fibers. A few studies have examined the energetic properties of skeletal muscle in domestic fowls; however, no information on muscle bioenergetics in broiler chickens selectively bred for faster growth is available. In this study, we aimed to characterize the mitochondrial contents and functions of chicken skeletal muscle consisting entirely of type I (oxidative) (M pubo-ischio-femoralis pars medialis), type HA (glycolytic/oxidative) (M pubo-ischio-femoralis pars lateralis), and type IIB (glycolytic) (M pectoralis) muscle fibers. Citrate synthase (CS) activity was the highest in type IIA muscle tissues and isolated mitochondria, among the muscle tissues tested. Although no difference was registered in mitochondrial CS activity between type IIB and type I muscles, tissue CS activity was significantly higher in the latter. Histochemical staining for NADH tetrazolium reductase and the ratio of muscle-tissue to mitochondrial CS activity indicated that type I, type HA, and type IIB muscle-fiber types showed decreasing mitochondrial content. Mitochondria from type I muscle exhibited a higher coupled respiration rate induced by pyruvate/malate, palmitoyl-CoA/malate, and palmitoyl-carnitine, as respiratory substrates, than type IIB-muscle mitochondria, while the response of mitochondria from type IIA muscle to those substrates was comparable to that of mitochondria from type I muscle. Type HA-muscle mitochondria exhibited the highest carnitine palmitoyltransferase-2 level among all tissues tested, which may contribute to the higher fatty acid oxidation in these mitochondria. The results suggest that mitochondrial abundance is one of the features differentiating metabolic characteristics of different chicken skeletal muscle types. Moreover, the study demonstrated that type IIA-muscle mitochondria may have distinct metabolic capacities.