Beef cattle industry in South Korea and molecular mechanisms of bovine intramuscular fat deposition

摘要

The livestock industry is the most important agricultural sector in South Korea，and the proportion of the livestock industry from total agricultural output is accounted for 40% in 2017. The intramuscular fat (IMF) deposition (marbling) is a most important trait (especially in the longissimus doris or longissimus thoracis) affecting beef quality and palatability of Korean cattle beef. The price of Korean cattle beef has been mainly determined by the marbling score or quality grade, and thus, farmershave extended slaughter age to get highly marbled-beef. The extension of slaughter age causes an increased inedible fat content and subsequently decreased fresh meat percent and yield grade. Moreover, there are growing health concerns (e.g. arteriosclerosis) among the consumers on the consumption of highly marbled-beef. The Korea Institute for Animal Products Quality Evaluation has recently revised the beef carcass grading system in the direction of decreasing importance of marbling score and strengthening importance of carcass yield. Functional genomics tools, including transcriptomics (real-time-PCR, microarray, RNA sequencing), have been applied toward understanding the molecular mechanisms of IMF deposition in Korean cattle. Our results suggest that the combined effects of increased lipid uptake, increased lipogenesis，anddecreased lipolysis may be involved in the increased IMF deposition in steers following castration of bulls. We have reported that extracellular matrix (ECM) components and ECM degrading factors may affect IMF deposition in the longissimus thoracis following castration. We also reported up-regulation of bone morphogenetic protein 2 and leptin/STAT3 signaling pathways in an increased IMF deposition following castration of bulls. Finally, we introduced a concept of “nutrigenomics m order to develop “a genome-based precision feeding” of Korean cattle steers.