title: Differential expression of genes related to gain and intake in the liver of beef cattle.
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 a 78 day 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 cellular transport, metabolism regulation, and immune function.
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, 68933-0166, USA. Christina.Zarek@UTSouthwestern.edu.
authors.forename: C M
authors.initials: CM
authors.lastname: Zarek
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, 68933-0166, USA. amanda.lindholm@ars.usda.gov.
authors.forename: A K
authors.initials: AK
authors.lastname: Lindholm-Perry
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, 68933-0166, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Kuehn
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, 68933-0166, USA.
authors.forename: H C
authors.initials: HC
authors.lastname: Freetly
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics*; D018925:Chemokines / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D007107:Immune System; D007249:Inflammation; D008099:Liver / Q000378:metabolism*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D012313:RNA / Q000032:analysis; D015398:Signal Transduction; D054875:Ubiquitination
chemical_list: D018925:Chemokines; D012313:RNA; D046988:Proteasome Endopeptidase Complex
keywords: Beef cattle; Cellular transport; Feed efficiency; Immune response; Metabolism; Steers; Transcriptome