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Title:Nutritional modulation of the transcriptome in adipose, liver, and polymorphonuclear leukocytes in peripartal dairy cows
Author(s):Agrawal, Alea
Advisor(s):Loor, Juan J
Contributor(s):Cardoso, Felipe; Rodriguez-Zas, Sandra
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Transition cow
Dairy cow
G-protein coupled receptors (GPCR)
Body condition score (BCS)
Polymorphonuclear (PMNL)
Abstract:Peripartal dairy cows undergo extensive changes in metabolism and experience immune system adaptations which can hinder short-term health, production, and longevity. Various prepartum nutritional strategies have been implemented to alleviate negative consequences and maximize benefits to both cow and dairy producer. With the objective of characterizing some of these nutrition-system interactions at a molecular level, two studies were conducted on peripartal dairy cows in order to 1) determine effects of body condition score (BCS) on adipose gene expression, or supplemental rumen-protected methionine on liver and polymorphonuclear (PMNL) gene expression of fatty acid-sensing G-protein coupled receptors (GPCRs), and 2) evaluate the effect of overfeeding during the dry period on the PMNL transcriptome. In the first study, cows were either 1) retrospectively classified as having high (HI; BCS > 3.75) or low (LO; BCS < 3.25) BCS at -3 wk from parturition, or 2) assigned to a control (CON) or methionine-supplemented (MET) dietary group during the dry period. Gene expression was determined through qPCR for four GPCRs: G-protein coupled receptor 40 (GPR40), G-protein coupled receptor 120 (GPR120), G-protein coupled receptor 84 (GPR84), and G-protein coupled receptor 109A (GPR109A, also known as hydroxycarboxylic acid receptor 2/3, HCAR2/3), throughout the transition period (-10, +7, and +20 or +30 d) in subcutaneous adipose tissue of HI and LO cows, and in liver and PMNL of CON and MET cows. In adipose tissue, GPR84 expression increased postpartum (P < 0.01) and in LO vs. HI cows at +7 d from parturition (P < 0.05). GPR120 expression decreased postpartum (P < 0.01), and GPR40 was not expressed. In PMNL, GPR40 expression gradually decreased over time and was lower in MET vs. CON cows (P < 0.05). GPR84 expression was higher in MET vs. CON (P < 0.05), and GPR120 was not expressed. In liver, GPCR were either not expressed, or were barely detectable with no significant effects. For the second study, PMNL were collected from the coccygeal vein at -14 and +7 d relative to parturition from cows which were overfed (OVE; NEL = 1.62 Mcal/kg DM) or control-fed (CON; NEL = 1.34 Mcal/kg DM) during the dry period. Transcriptomes of OVE vs. CON were compared via microarray technology. Subsequently, KEGG pathway analysis of 1806 differentially expressed genes (DEG; FDR < 0.05) was conducted using the Dynamic Impact Approach (DIA). The top 20 impacted (i.e.: most relevant) pathways fell into three KEGG categories: Metabolism, Genetic Information Processing, and Organismal Systems. Individual impacted pathways indicated that overfeeding was related to several important metabolic and functional PMNL adaptations during the transition period. Many of these pathways and flux (i.e.: direction) of their impact also supported that transcription-level changes were consistent with signs of chronic inflammation, e.g., prioritization of survival over immune function. Combined results of these studies demonstrate that peripartal cows experience important nutrition-driven, transcription-level adaptations with regard to metabolism, e.g., glucose and lipid metabolism, and immunity, e.g., neutrophil functions. It appears that manipulating BCS and supplementing methionine could be effective nutritional strategies to improve immune function and glucose-lipid metabolic networks, while overfeeding should be avoided to prevent immune dysfunction. Further work on fatty-acid sensing GPCR may contribute to peripartal research, and other gene targets can be derived from microarray studies. Overall, profiling the transcriptome can provide great insight into relationships between immune and metabolic networks, and health outcomes in peripartal dairy cows.
Issue Date:2016-07-19
Rights Information:Copyright 2016 Alea Agrawal
Date Available in IDEALS:2016-11-10
Date Deposited:2016-08

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