Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/21/2016
Publication Date: 3/7/2016
Citation: Zarek, C.M., Lindholm-Perry, A.K., Freetly, H.C. 2016. Differential expression of genes in the liver associated with gain and intake in beef steers [abstract]. Journal of Animal Science. 94(Supplement 2):185.
Technical Abstract: The purpose of this study was to identify genes associated with gain and intake in the liver in beef cattle. The liver uses 25% of the body’s energy, while constituting less than 2% of total body weight. It is likely that the liver plays a key role in gain and intake due to its high energy utilization and role in metabolism. Yearling, crossbred-steers were put on a 78-d feed trial. Average daily gain and average daily intake were calculated at the end of the trial. The 16 steers with the greatest deviation from the bivariate mean were selected for slaughter: 4 steers with high gain-high intake (HG-HI); 4 with high gain-low intake (HG-LI), 4 with low gain-low intake (LG-LI); and 4 with low gain-high intake (LG-HI). Liver samples were collected during the slaughter and flash frozen in liquid nitrogen. RNA was extracted from the samples, and used for a microarray assay. Genes were evaluated for differential expression by one-way between-subject ANOVA and were considered differentially expressed with fold changes of =-1.75 and =1.75 and P = 0.05. The differential expression of genes was determined HG-LI vs. HG-HI, HG-LI vs. LG-LI, and HG-LI vs. LG-HI steers. Genes involved in growth and differentiation (i.e. GDF3, ANGPT2, EGR1) were upregulated in HG-LI animals, compared to HG-HI and LG-LI animals. Genes involved in protein metabolism were downregulated in the HG-LI steers compared to the HG-HI steers (i.e. FARSB, NT5E). Several genes involved in glucose and lipid metabolism pathways are differentially expressed between HG-LI and LG-HI animals (i.e. LPIN1, ADIPOR2, PDK4).