The IGF‐1/Akt/S6 pathway and expressions of glycolytic myosin heavy chain isoforms are upregulated in chicken skeletal muscle during the first week after hatching

Abstract

Skeletal muscle mass is an important trait in the animal industry. We previously reported an age-dependent downregulation of the insulin-like growth factor 1 (IGF-1)/Akt/S6 pathway, major protein synthesis pathway, in chicken breast muscle after 1 week of age, despite a continuous increase of breast muscle weight. Myosin heavy chain (HC), a major protein in muscle fiber, has several isoforms depending on chicken skeletal muscle types. HC I (fast-twitch glycolytic type) is known to be expressed in adult chicken breast muscle. However, little is known about the changes in the expression levels of protein synthesis-related factors and HC isoforms in perihatching chicken muscle. In the present study, protein synthesis-related factors, such as IGF-1 messenger RNA (mRNA) levels, phosphorylation of Akt, and phosphorylated S6 content, increased in an age-dependent manner after post-hatch day (D) 0. The mRNA levels of HC I, III and V (fast-twitch glycolytic type) dramatically increased after D0. The increase ratio of breast muscle weight was approximately 1100% from D0 to D7. To our knowledge, these findings provide the first evidence that upregulation of protein synthesis pathway and transcription of fast twitch glycolytic HC isoforms play critical roles in the increase of chicken breast muscle weight during the first week after hatching.

Skeletal muscle and metabolic flexibility in response to changing energy demands in wild birds

“…IGF-1 also promotes skeletal muscle growth through the PI3K/ Akt pathway in chickens (Deng et al, 2014;Yu et al, 2015;Nakashima and Ishida, 2018;Nakashima and Ishida, 2019). Even though the IGF-1 axis is a prime target for muscle remodeling in poultry (e.g., Tomas et al, 1998;Saneyasu et al, 2016;Saneyasu et al, 2017;Chen et al, 2018), the IGF-1 axis has received much less research attention in wild birds, with reference to muscle remodeling for phenotypic flexibility, compared with the myostatin signaling pathway. Adélie penguins chicks (Pygoscelis adeliae) expressed high IGF-1 mRNA in pectoralis muscle during a rapid growth period, indicating that it plays an important role in the development of an enhanced muscle phenotype (Dégletagne et al, 2013).…”

Research progress on regulating factors of muscle fiber heterogeneity in poultry: a review

“…After birth, the proportion of fast-twitch fibers gradually increases, indicating a shift from slow to fast muscle fibers. Saneyasu et al (2017) also found significant changes in the MyHC subtype gene and Tn1 gene from oxidative to glycolytic types in the PM muscle of hens during the first week post-hatching, revealing the basis for physiological and chemical changes in the muscle fibers post-hatching. It is generally believed that increasing age after birth is also crucial for fiber type transitions.…”

miRNA-seq analysis in skeletal muscle of chicken and function exploration of miR-24-3p

“…Chicken meat provides a large amount of high-quality protein for human beings ( Ren, et al, 2018 ), in which skeletal muscle plays a major role. Therefore, the growth and development of skeletal muscle have always been a focus of the broiler industry ( Saneyasu, et al, 2017 ). Yellow-feathered broilers are especially popular in China in recent years ( Jiang, et al, 2018 ) because of their better meat quality ( Jiang, et al, 2019 ; Wang, et al, 2019 ).…”