Systems Biology Approach to Determine Molecular Mechanisms Associated with Feed Efficiency in Nelore Cattle

Abstract

Increase productivity, profitability and reduce environmental impact of livestock are among the main selection objectives of beef cattle and can be achieved by identifying animals with high feed efficiency (FE). Because it is a trait influenced by different biological processes, understanding their regulation at molecular level is critical to identify superior animals quickly and at lower cost. We found earlier that low FE animals have greater fat deposition, cholesterol, GGT and have liver transcriptome associated with inflammation and lipid metabolism. The aim of this project is to determine a model of molecular mechanisms associated with feed efficiency in Nellore cattle using a systems biology approach based on the integration of genomic, transcriptomic and epigenômicas analyzes in multiple tissues. For this purpose, 16 animals evaluated as extremes of FE had pituitary, hypothalamus, adrenal and small intestine samples collected. Through gene expression and co-expression analysis, regulatory genes and central biological mechanisms related to FE will be identified. Subsequently, functional polymorphisms associated with FE will be identified and then, epigenetic mechanisms responsible for the results previously obtained will be evaluated by hypermethylated CpG islands and miRNA expression analysis. We believe that the integration of omics data evaluated in multiple tissues will allow us to propose a biological model for systemic understanding of feed efficiency, directing future approaches for selection and handling of animals.