Iron Content Affects Lipogenic Gene Expression in the Muscle of Nelore Beef Cattle

Abstract

Iron (Fe) is an essential mineral for metabolism and plays a central role in a range of biochemical processes. Therefore, this study aimed to identify differentially expressed (DE) genes and metabolic pathways in Longissimus dorsi (LD) muscle from cattle with divergent iron content, as well as to investigate the likely role of these DE genes in biological processes underlying beef quality parameters. Samples for RNA extraction for sequencing and iron, copper, manganese, and zinc determination were collected from LD muscles at slaughter. Eight Nelore steers, with extreme genomic estimated breeding values for iron content (Fe-GEBV), were selected from a reference population of 373 animals. From the 49 annotated DE genes (FDR<0.05) found between the two groups, 18 were up-regulated and 31 down-regulated for the animals in the low Fe-GEBV group. The functional enrichment analyses identified several biological processes, such as lipid transport and metabolism, and cell growth. Lipid metabolism was the main pathway observed in the analysis of metabolic and canonical signaling pathways for the genes identified as DE, including the genes FASN, FABP4, and THRSP, which are functional candidates for beef quality, suggesting reduced lipogenic activities with lower iron content. Our results indicate metabolic pathways that are partially influenced by iron, contributing to a better understanding of its participation in skeletal muscle physiology.

Fig 1. Ranking of the biological processes based on the terms of Gene Ontology (GO-Slim) for the differentially expressed genes identified in Nelore steers with high and low genomic breeding value for iron content in the Longissimus dorsi muscle.

The bar represents each category of the biological process. The number of genes per category is indicated above the bar.

Fig 2. Lipid metabolism related network of differentially expressed genes between high and low iron content in the Nelore steers Longissimus dorsi muscle.

Genes in green and red are down- and up-regulated in the LowFe group, respectively. Color intensity refers to fold change estimates. Dotted arrows represent indirect interactions, and orange, blue, gray, and yellow colors denote activation, inhibition, unpredicted effect, and inconsistent effect, respectively. Reprinted from [QIAGEN’s Ingenuity^® Pathways Analysis] under a CC BY license, with permission from QIAGEN Silicon Valley, original copyright [200–2015 QIAGEN].

Fig 3. Cell development and a differentiation-related network of differentially expressed genes between high and low iron content in the Nelore steers Longissimus dorsi muscle.

Genes presented in green and red are down- and up-regulated in the LowFe group, respectively. Color intensity refers to fold change estimates. Dotted arrows represent indirect interactions, and colors orange, blue, gray, and yellow denote activation, inhibition, unpredicted effect, and inconsistent effect, respectively. Reprinted from [QIAGEN’s Ingenuity^® Pathways Analysis] under a CC BY license, with permission from QIAGEN Silicon Valley, original copyright [200–2015 QIAGEN].