Transcriptional Networks Influencing Residual Feed Intake in Nelore Beef Cattle

Feed efficiency-related traits are increasingly being studied in livestock because of their importance to decreasing greenhouse gas emissions and improving industry profitability and sustainability. Recent developments in molecular genetics, such as platforms for genome-wide sequencing, provide an opportunity to identify genes and pathways underlying variation in production traits. In particular, these platforms allow the elucidation of the transcriptional networks that underlie phenotypic variation in traits such as growth and energy balance. We conducted a genome-wide transcriptome profiling study of hepatic tissue from Nelore beef cattle selected to be genetically divergent for Residual Feed Intake (RFI; N = 10 high-RFI and N = 10 low-RFI) to reveal key metabolic and cell signaling networks. A total of 112 annotated genes were differentially expressed between animals with efficient and inefficient RFI phenotypes. These genes are members of several gene clusters that are related to the transport of molecules through the cell membrane and their catalysis, which is essential for the absorption of nutrients. Genes with functions in cellular signaling, growth and proliferation, cell death and survival were also found. Some previously described mechanisms related to feed efficiency such as xenobiotic metabolism were supported; however, new pathways including NRF2-mediated oxidative stress, melatonin degradation and glutathione were also identified as regulating RFI in Nelore cattle. These findings improve our understanding of the metabolic mechanisms underlying feed efficiency in beef cattle and may be useful for developing new strategies to improve feed efficiency.