Abstract

Gene expression profiles in liver of dairy cows in response to feed restriction using a bovine cDNA microarray 

J. J. Loor, D. B. Carlson, R. E. Everts, S. L. Rodriguez-Zas, H. A. Lewin, and J. K. Drackley.  University of Illinois, Urbana.

ADSA/ASAS/PSA Annual Joint Meeting, St. Louis, July 25-29, 2004

Dairy cows decrease DMI around parturition but little is known about associated changes on tissue gene expression.  We studied the effects of acute feed restriction on hepatic gene expression using cDNA microarray technology.  During a 14-d period, six Holstein cows in mid-lactation (132 ± 38 DIM) had ad libitum access to a TMR (NR) or were restricted to 50% of previous 5-d DMI (FR) from d 10 through 14.  Liver was biopsied on d 14.  A microarray consisting of 7,872 cDNA inserts was used for transcript profiling.  Annotation was based on similarity searches using BLASTN and TBLASTX against human and mouse UniGene databases and the human genome.  Cy3- and Cy5-labelled cDNA from liver and a reference standard (derived from a mixture of cattle tissues) were used for hybridizations (24 microarrays).  Loess-normalized log-transformed ratios (liver/standard) were used to detect differential gene expression.  Ninety-nine differentially expressed genes were found with an experiment-wise significance of 0.10 using Benjamini and Hochberg’s False Discovery Rate and a global gene error model (to account for the dependence of variation on signal intensities).  Forty-six were 0.9- to 0.5-fold lower and 53 were 1- to 5-fold greater with FR.  Genes associated with intracellular acyl-CoA ester transport, stress responses, and the tricarboxylic acid cycle were among those downregulated by FR.  In contrast, FR increased hepatic expression of genes with links to immune responses, antioxidant activities, signal transduction, and apoptosis.  Our results demonstrate that hepatic gene expression is altered in response to plane of nutrition. (Supported by award 2001-35206-10946 from NRI Competitive Grants Program/CSREES/USDA). Journal of Dairy Science, 87(Suppl. 1):T136.