Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2018 Investigating the interplay of physiological and molecular mechanisms underpinning programmable aspects of heat stress in pigs Jacob Seibert Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Agriculture Commons, Animal Sciences Commons, Molecular Biology Commons, and the Physiology Commons Recommended Citation Seibert, Jacob, "Investigating the interplay of physiological and molecular mechanisms underpinning programmable aspects of heat stress in pigs" (2018). Graduate Theses and Dissertations. 16878. https://lib.dr.iastate.edu/etd/16878 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Investigating the interplay of physiological and molecular mechanisms underpinning programmable aspects of heat stress in pigs by Jacob Todd Seibert A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Molecular, Cellular, and Developmental Biology Program of Study Committee: Lance Baumgard, Co-major Professor Jason Ross, Co-major Professor Steven Lonergan James Reecy Christopher Tuggle The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this dissertation. The Graduate College will ensure this dissertation is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2018 Copyright © Jacob Todd Seibert, 2018. All rights reserved. ii DEDICATION I dedicate this dissertation to every person that has pushed me and encouraged me to keep going and to do my best with anything that I set my mind to, family, friends, coaches, mentors, and teachers. "The price of success is hard work, dedication to the job at hand, and the determination that whether we win or lose, we have applied the best of ourselves to the task at hand." - Vince Lombardi iii TABLE OF CONTENTS Page LIST OF FIGURES ........................................................................................................... vi LIST OF TABLES ............................................................................................................. ix ACKNOWLEDGMENTS ................................................................................................. xi ABSTRACT ..................................................................................................................... xiv CHAPTER 1. GENERAL INTRODUCTION ................................................................... 1 The Impact of Heat Stress on Livestock Agriculture and Food Security ...................... 1 Physiological Responses to HS ..................................................................................... 2 Thermotolerance ............................................................................................................ 6 Genetics of Thermotolerance ................................................................................... 6 Acquired Thermotolerance ....................................................................................... 8 Heat Shock Proteins and Cellular Thermotolerance ................................................ 9 Developmental Programming and Epigenetics ........................................................... 11 Developmental Programming and Effects in Postnatal Life .................................. 11 Heat Stress Effects on the Developing Offspring .................................................. 14 Types of Epigenetic Marks and Effects on Transcriptional Regulation ................ 15 Epigenetic Events in Developmental Programming .............................................. 21 Heat Stress Influence on Epigenetic Marks ........................................................... 23 Summary ...................................................................................................................... 27 References ................................................................................................................... 28 CHAPTER 2. CHARACTERIZING THE ACUTE HEAT STRESS RESPONSE IN GILTS: I. THERMOREGULATORY AND PRODUCTION VARIABLES .................. 47 Abstract ........................................................................................................................ 47 Introduction ................................................................................................................. 49 Materials and Methods ................................................................................................ 50 Animals and Experimental Design ......................................................................... 50 Production and Thermoregulatory Measurements ................................................. 51 Determination of HS Tolerance and Susceptibility Based on the Thermoregulatory Response ................................................................................... 52 Statistical Analysis ................................................................................................. 52 Results ......................................................................................................................... 53 Thermoregulatory and Productivity Variables have Marginal Relationships during TN Conditions ............................................................................................. 53 Minor Relationships between Thermoregulation and Production Parameters are Observed during HS Conditions ...................................................................... 53 Relationship between Thermoregulatory Indices and Production Characteristics during TN and HS Conditions ....................................................... 54 iv Pigs Retrospectively Classified as SUS had Improved Production Characteristics during TN Conditions yet Impaired Thermoregulatory Ability during HS Compared to TOL Pigs ......................................................................... 54 Discussion .................................................................................................................... 55 Conclusion ................................................................................................................... 59 Acknowledgements ..................................................................................................... 60 Declaration of Interest ................................................................................................. 60 Literature Cited ............................................................................................................ 60 Tables and Figures ....................................................................................................... 64 CHAPTER 3. EFFECTS OF HEAT STRESS AND INSULIN SENSITIZERS ON PIG ADIPOSE TISSUE .................................................................................................... 73 Abstract ........................................................................................................................ 74 Introduction ................................................................................................................. 75 Materials and Methods ................................................................................................ 76 Animals and Experimental Design ......................................................................... 76 Production and Thermoregulatory Measurements ................................................. 78 Blood Sampling and Analysis ................................................................................ 79 Tissue Collection and Fatty Acid Composition Analysis ...................................... 79 Adipose Moisture Content and Morphology Analysis ........................................... 80 Statistical Analysis ................................................................................................. 81 Results ......................................................................................................................... 82 Thermoregulatory, Production, and Blood Indices ................................................ 82 Fatty Acid Composition ......................................................................................... 83 Back Fat Thickness, Adipocyte Area, and Adipose Moisture Content .................. 83 Discussion .................................................................................................................... 84 Conclusion ................................................................................................................... 87 Acknowledgements ..................................................................................................... 88 Literature Cited ............................................................................................................ 88 Tables and Figures ....................................................................................................... 93 CHAPTER 4. DIFFERENTIATING BETWEEN THE EFFECTS OF HEAT STRESS AND LIPOPOLYSACCHARIDE ON PORCINE OVARIAN HEAT SHOCK