Identification of Differentially Expressed Genes in Different Types of Broiler Skeletal Muscle Fibers Using the RNA-seq Technique.

Han Wang,Zhonghao Shen,Ke He,Ayong Zhao,Songbai Yang,Feifei Yan,Xiaolong Zhou

doi:10.1155/2020/9478949

Abstract

The difference in muscle fiber types is very important to the muscle development and meat quality of broilers. At present, the molecular regulation mechanisms of skeletal muscle fiber-type transformation in broilers are still unclear. In this study, differentially expressed genes between breast and leg muscles in broilers were analyzed using RNA-seq. A total of 767 DEGs were identified. Compared with leg muscle, there were 429 upregulated genes and 338 downregulated genes in breast muscle. Gene Ontology (GO) enrichment indicated that these DEGs were mainly involved in cellular processes, single organism processes, cells, and cellular components, as well as binding and catalytic activity. KEGG analysis shows that a total of 230 DEGs were mapped to 126 KEGG pathways and significantly enriched in the four pathways of glycolysis/gluconeogenesis, starch and sucrose metabolism, insulin signalling pathways, and the biosynthesis of amino acids. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the differential expression of 7 selected DEGs, and the results were consistent with RNA-seq data. In addition, the expression profile of MyHC isoforms in chicken skeletal muscle cells showed that with the extension of differentiation time, the expression of fast fiber subunits (types IIA and IIB) gradually increased, while slow muscle fiber subunits (type I) showed a downward trend after 4 days of differentiation. The differential genes screened in this study will provide some new ideas for further understanding the molecular mechanism of skeletal muscle fiber transformation in broilers.

Highlights

Chicken is widely welcomed by consumers because it is low in fat, is low in cholesterol, and has no religious restrictions
Type II muscle fibers can be categorized into a fast-twitch oxidation type (IIA), a fast-twitch glycolytic type (IIB), and a super-fast-twitch type (IIX) [10, 11]
The results showed that the expression of MYH3 in the breast muscle was significantly higher than that in the leg muscle, while the expression of MYH1C showed the opposite result (Figure 1)

Summary

Introduction

Chicken is widely welcomed by consumers because it is low in fat, is low in cholesterol, and has no religious restrictions. Sex, heredity, environment, nutrition, and intramuscular fat content (IMF) are all important factors affecting chicken quality [3,4,5,6]. Studies have shown that muscle fiber properties were an essential factor affecting the meat quality of chicken [7, 8]. Skeletal muscle is one of the most important components of meat-producing animals, accounting for approximately 45%~60% of the whole animal body [9]. According to the characteristics of contraction and metabolism, skeletal muscle fibers can be roughly divided into two types: slow-twitch (type I) and fast-twitch (type II) muscles. It was found that muscles with a higher proportion of oxidized muscle fibers had better meat quality [13]

Methods

Results

Discussion

Conclusion