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THE ABDOMINAL FAT CONTRIBUTION TO ADIPOSITY IN CHICKENS DIVERGENTLY SELECTED FOR FATNESS OR GROWTH: CROSS-MODEL ELUCIDATION AND VALIDATION OF GENE EXPRESSION by Christopher William Resnyk A thesis submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Master of Science in Animal Science Summer 2013 © 2013 Christopher William Resnyk All Rights Reserved THE ABDOMINAL FAT CONTRIBUTION TO ADIPOSITY IN CHICKENS DIVERGENTLY SELECTED FOR FATNESS OR GROWTH: CROSS-MODEL ELUCIDATION AND VALIDATION OF GENE EXPRESSION by Christopher William Resnyk Approved: __________________________________________________________ Larry A. Cogburn III, Ph.D. Professor in charge of thesis on behalf of the Advisory Committee Approved: __________________________________________________________ Jack Gelb, Jr., Ph.D. Chair of the Department of Animal and Food Sciences Approved: __________________________________________________________ Mark Rieger, Ph.D. Dean of the College of Agriculture and Natural Resources Approved: __________________________________________________________ James G. Richards, Ph.D. Vice Provost for Graduate and Professional Education ACKNOWLEDGMENTS This work was supported by a grant from the United States Department of Agriculture, Initiative for Future Agricultural and Food Systems, Animal Genome Program (USDA-IFAFS; Award # 00-52100-9614) and a grant from the USDA Cooperative State Research, Education, and Extension Service (CSREES; Award # 2009-34562-20008) to the Avian Biosciences Center, University of Delaware. I want to thank my collaborators on this work: Sam Aggrey, Wilfrid Carre, Chuming Chen, Larry Cogburn, Michel Duclos, Elisabeth Le Bihan-Duval, Hongzhan Huang, Tom Porter, Jean Simon, Xiaofei Wang, and Cathy Wu. Further, the longitudinal study and tissue sampling of the divergent lines required the contribution of a large number of scientists and technicians from the laboratories of INRA UR83 and from the breeding facilities in Nouzilly, France. Although not named, each individual’s essential contribution toward completion of this project is gratefully acknowledged. Thank you to Sandra Rodriguez-Zas for completing the statistical analysis on the HG and LG microarray data, and to Robert Settlage and Wyatt McMahon for analysis of the HG and LG RNA sequencing experiment. The contributions of each collaborator made this work possible. Thank you. iii I would like to thank my committee members for their support. First, I have to thank Larry Cogburn for seeing potential in me as an undergraduate and giving me a “home” for the last three years. You became not only my advisor, but also my mentor and friend. You are an inspiration and have provided me with the necessary tools to be an effective scientific investigator. Thank you to Behnam Abasht, Gary Laverty, and Cathy Wu for serving on my thesis committee. I would also like to thank Jack Gelb and Mark Parcells for their assistance throughout my degree. Your support has been greatly appreciated over the last few years. Thank you. Thank you to all Worrilow Hall graduate and undergraduate students who helped and/or interacted with me throughout my degree, especially Nick Siano for being a friend and providing the competition that I needed to succeed over the past 6 years. I want to give a special thank you to my parents and grandparents who struggled and persevered so that I could have this wonderful opportunity. Your contribution to my success will never be overlooked. Finally, thank you to my beautiful wife for all of her support and unconditional love during this process. I think all of the clicking has paid off! This thesis is dedicated to my loving wife Jessica and my sisters Amanda and Kayla. iv TABLE OF CONTENTS LIST OF TABLES ........................................................................................................ ix LIST OF FIGURES ........................................................................................................ x ABSTRACT ................................................................................................................ xiii Chapter 1 BACKGROUND ................................................................................................ 1 1.1 The Domestic Chicken as a Model of Obesity .......................................... 1 1.1.1 Lipid breakdown and synthesis are conserved in chickens ........... 1 1.1.2 Intriguing features of avian metabolism bolster the chicken as a model for metabolic disorders .................................................... 6 1.2 Our Models for Studying Fatness and Leanness ....................................... 8 1.2.1 The fat line and lean line chickens ................................................ 8 1.2.2 The high growth and low growth chickens ................................. 10 1.3 The Abdominal Fat Contribution to Adiposity ....................................... 12 1.4 Important Processes Regulating Fatness and Leanness in Abdominal Fat ............................................................................................................ 13 1.4.1 Ligand activated transcription factor signaling ........................... 13 1.4.1.1 Retinoid metabolism, signaling and transcription factor activation ............................................................ 14 1.4.2 Hemostasis ................................................................................... 16 1.5 References ............................................................................................... 20 2 LONGITUDINAL MICROARRAY ANALYSIS OF ABDOMINAL FAT IN GENETICALLY FAT AND LEAN CHICKENS ...................................... 28 2.1 Introduction ............................................................................................. 28 2.2 Methods ................................................................................................... 29 v 2.2.1 Animals and tissue collection ...................................................... 29 2.2.2 Microarray analysis ..................................................................... 30 2.2.3 Quantitative RT-PCR analysis .................................................... 33 2.3 Results ..................................................................................................... 35 2.3.1 Phenotypic measurements ........................................................... 35 2.3.2 Abdominal fat gene expression ................................................... 36 2.3.3 Ingenuity Pathway Analysis (IPA) of differentially expressed gene sets ....................................................................................... 37 2.3.4 Higher expression of lipogenic genes in adipose tissue of FL chickens ....................................................................................... 45 2.3.5 Ligand activated nuclear receptors and other transcription factors .......................................................................................... 52 2.3.6 Correlation of gene expression between microarray and qRT- PCR analyses ............................................................................... 62 2.4 Discussion ................................................................................................ 63 2.4.1 Higher expression of hemostatic factors in adipose tissue of LL chickens ................................................................................. 64 2.4.2 Adipokines in abdominal fat of FL and LL chickens .................. 67 2.4.3 Retinol metabolism and retinoic acid signaling in adipose tissue ............................................................................................ 70 2.4.4 Visceral adipose tissue as a major site of lipogenesis in chickens ....................................................................................... 72 2.4.5 Increased lipolysis in abdominal fat of LL chickens ................... 77 2.5 Chapter Summary .................................................................................... 78 2.6 References ............................................................................................... 80 3 DEEP RNA SEQUENCE ANALYSIS OF ABDOMINAL FAT IN GENETICALLY FAT AND LEAN CHICKENS AT 7 WEEKS OF AGE .... 91 3.1 Introduction ............................................................................................. 91 3.2 Methods ................................................................................................... 93 3.2.1 Animals and tissue preparation ................................................... 93 3.2.2 RNA extraction, library preparation and RNA sequencing ......... 94 3.2.3 RNA sequence analysis ............................................................... 95 3.2.3.1 Sequence data filtering ................................................. 95 3.2.3.2 Read mapping and transcript/gene identification ......... 95 3.2.3.3 Differential expression analysis ................................... 96 vi 3.2.4 Quantitative RT-PCR verification analysis ................................. 97 3.3 Results ..................................................................................................... 98 3.3.1 Mapped reads: genes and transcripts detected ............................. 98 3.3.2 Abdominal fat transcriptome of FL and LL chickens at 7 wk .. 100 3.3.3 Ingenuity Pathway Analysis (IPA) of gene interactions and functional pathways ................................................................... 101 3.3.3.1 Analysis of the highest expressed processes in abdominal