Differential transcript abundance in adipose tissue of mature beef cows during feed restriction and realimentation

Authors: CUNNINGHAM, HANNAH - University Of Wyoming; CAMMACK, KRISTI - South Dakota State University; Hales Paxton, Kristin; Freetly, Harvey; Lindholm-Perry, Amanda

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2018
Publication Date: 3/13/2018
Citation: Cunningham, H.C., Cammack, K.M., Hales, K.E., Freetly, H.C., Lindholm-Perry, A.K. 2018. Differential transcript abundance in the adipose tissue of mature beef cows during feed restriction and realimentation. PLoS One. 13(3):e0194104. https://doi.org/10.1371/journal.pone.0194104.
DOI: https://doi.org/10.1371/journal.pone.0194104

Interpretive Summary: Feed costs for mature cows account for over 70% of the annual expenditures in cow/calf production. During the production year the cow uses nutrients from feed to support conceptus growth, milk production, work (grazing and locomotion), but the majority of nutrients are used to support basic biological maintenance requirements. Beef cows can experience periods of nutrient restriction, as well as increases in abundance of nutrients in a production setting and the animal’s tissues and organs must respond and adjust to these; however, the molecular responses of these tissues have not been well-studied. The objective of this study was to determine whether cows that differ in their ability to gain weight during abundance of feed after feed restriction also differ in the relative abundance of gene transcripts for enzymes associated with lipid turnover in adipose tissue. Mature cows were subjected to feed restriction followed by ad libitum feed. This study allowed us to determine the changes in biological responses of adipose tissue in beef cows with variation in body weight gain at both low and high levels of nutrient abundance. Genes involved in lipid metabolism, mitochondrial respiration and oxidative phosphorylation pathways appear to be critical to mature cows during times of abundant feed after feed restriction.

Technical Abstract: Feed costs account for over 70% of the annual expenditures in cow/calf production. During the production year the cow uses nutrients to support conceptus growth, milk production, work (grazing and locomotion), and maintenance requirements. The majority of the nutrients are used to support maintenance. Substrate cycling has been identified as one of the major contributors toward energy expenditure associated with maintenance in mature cows. The objective of this study was to determine whether beef cows that differ in the efficiency of weight gain differ in the relative abundance of transcripts for metabolic regulation in adipose tissue. Mature beef cows were subjected to feed restriction followed by ad libitum feed. Adipose tissue from twelve cows with high (n=6) and low (n=6) gain based on growth performance during the ad libitum feeding period was evaluated for transcriptome expression differences. A total of 496 genes were differentially expressed and passed Bonferroni correction for the animals with greater gain between restriction and realimentation and 491 genes were differentially expressed among animals with lesser gains between feed restriction and realimentation. Of these two differentially expressed gene lists, 144 genes were common between animals with greater and those with lesser gain. Enriched biological processes included the TCA cycle, oxidative phosphorylation, respiratory electron transport chain and fatty acid metabolic processes. Specific to adipose tissue of low gaining animals was glycolysis and to high gain animals was coenzyme, steroid, cellular amino acid, nitrogen compound metabolic processes, and sensory perception. The oxidative phosphorylation, mitochondrial dysfunction and cholesterol biosynthesis pathways were commonly associated with the high gain animals between feed restriction and realimentation, as well as with the low gaining animals between the two time points. Unique to the high gaining animals were valine degradation and LPS/IL-1 mediated inhibition of RXR function pathways. In this discovery study, genes involved in lipid metabolism, mitochondrial respiration and oxidative phosphorylation pathways appear to be critical to mature cows during times of abundant feed after feed restriction.