Comparison of Metabolic Network between Muscle and Intramuscular Adipose Tissues in Hanwoo Beef Cattle Using a Systems Biology Approach.

Hyun-Jeong Lee,Duhak Yoon,Woonsu Kim,Hye-Sun Park,Seongwon Seo

doi:10.1155/2014/679437

Abstract

The interrelationship between muscle and adipose tissues plays a major role in determining the quality of carcass traits. The objective of this study was to compare metabolic differences between muscle and intramuscular adipose (IMA) tissues in the longissimus dorsi (LD) of Hanwoo (Bos taurus coreanae) using the RNA-seq technology and a systems biology approach. The LD sections between the 6th and 7th ribs were removed from nine (each of three cows, steers, and bulls) Hanwoo beef cattle (carcass weight of 430.2 ± 40.66 kg) immediately after slaughter. The total mRNA from muscle, IMA, and subcutaneous adipose and omental adipose tissues were isolated and sequenced. The reads that passed quality control were mapped onto the bovine reference genome (build bosTau6), and differentially expressed genes across tissues were identified. The KEGG pathway enrichment tests revealed the opposite direction of metabolic regulation between muscle and IMA. Metabolic gene network analysis clearly indicated that oxidative metabolism was upregulated in muscle and downregulated in IMA. Interestingly, pathways for regulating cell adhesion, structure, and integrity and chemokine signaling pathway were upregulated in IMA and downregulated in muscle. It is thus inferred that IMA may play an important role in the regulation of development and structure of the LD tissues and muscle/adipose communication.

Highlights

Hanwoo, the dominant breed for beef production in Korea, is known for yielding high quality beef with intense marbling and a high percentage of unsaturated oleic fatty acid [1]
The marbling score is determined by the degree of intramuscular adipose (IMA) deposition in the exposed longissimus dorsi (LD) muscle tissue at the 13th rib interface
More than 99.5% of the reads were remained after the quality filtering passed through the quality control, and more than 95.9% of these were mapped to the reference genome (Supplementary Table 1; see Supplementary Material available online at http://dx.doi.org/10.1155/ 2014/679437)

Summary

Introduction

The dominant breed for beef production in Korea, is known for yielding high quality beef with intense marbling and a high percentage of unsaturated oleic fatty acid [1]. The marbling score is determined by the degree of intramuscular adipose (IMA) deposition in the exposed longissimus dorsi (LD) muscle tissue at the 13th rib interface. Understanding the interrelationship between muscle and adipose tissues in LD is important for improving carcass traits in Hanwoo beef cattle. There are biological differences between SUA and IMA tissues in terms of development, lipid biosynthesis, and substrate preference [3]. It is reported that the adipose tissue plays a critical role in insulin sensitivity, substrate selection, and oxidative metabolism of skeletal muscle [7, 8]. Little has been studied on differences in metabolic gene network between muscle and IMA in an aspect of deciphering cross communication between these tissues in the LD of beef cattle

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