Submitted to: BMC Research Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2016
Publication Date: 1/3/2017
Publication URL: http://handle.nal.usda.gov/10113/5700671
Citation: Zarek, C.M., Lindholm-Perry, A.K., Kuehn, L.A., Freetly, H.C. 2017. Differential expression of genes related to gain and intake in the liver of beef cattle. BMC Research Notes. 10:1. doi:10.1186/s13104-016-2345-3.
Interpretive Summary: The highest cost of raising cattle for beef is the cost of feed. To reduce this cost and increase productivity, biomarkers could be used to select for cattle that gain acceptable body weights while consuming less feed. In order to determine which genes may impact these abilities, we conducted a study with crossbred steers that measured their weight gain and feed intake over 78 days. At the end of those 78 days, sixteen steers with the greatest and lowest body weight gain and feed intake were selected for this study. The selected steers were classified into four groups: high gain–high intake, high gain–low intake, low gain–low intake, and low gain–high intake. Liver samples were collected and analyzed differences in gene expression between the groups of steers. A total of 729 genes were differentially expressed. These genes were analyzed for representation among pathways or biological processes. Pathways related to protein turnover, transport, and immune function/inflammatory response were identified. The pathways identified suggest that immune response, transporter activity, and protein degradation within the liver may be contributing to cattle feed intake and gain phenotypes.
Technical Abstract: Background: To better understand which genes play a role in cattle feed intake and gain, we evaluated differential expression of genes related to gain and intake in the liver of crossbred beef steers. Based on past transcriptomics studies on cattle liver, we hypothesized that genes related to metabolism regulation and the inflammatory response would be differentially expressed. This study used 16 animals with diverse gain and intake phenotypes to compare transcript abundance after an ad libitum feed study. Results: A total of 729 genes were differentially expressed. These genes were analyzed for over-representation among biological and cellular functions, and pathways. Cell transport processes and metabolic processes, as well as functions related to transport were identified. Pathways related to immune function, such as the proteasome ubiquitination pathway and the chemokine signaling pathway, were also identified. Conclusions: Our results were consistent with past transcriptomics studies that have found immune and transport processes play a role in feed efficiency. Gain and intake are impacted by complex processes in the liver, which include metabolism regulation, immune function, and transportation within cells.