Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2012 Defining physiological differences between gilts divergently selected for residual feed intake Amanda Jean Harris Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Agriculture Commons, and the Animal Sciences Commons Recommended Citation Harris, Amanda Jean, "Defining physiological differences between gilts divergently selected for residual feed intake" (2012). Graduate Theses and Dissertations. 12775. https://lib.dr.iastate.edu/etd/12775 This Thesis 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]. Defining physiological differences between gilts divergently selected for residual feed intake by Amanda Jean Harris A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Animal Physiology Program of Study Committee: Nicholas K. Gabler, Major Professor John F. Patience Jack C. M. Dekkers Jason W. Ross Iowa State University Ames, Iowa 2012 Copyright © Amanda Jean Harris, 2012. All rights reserved. ii Table of Contents Table of Contents ....................................................................................................... ii Table of Figures ......................................................................................................... v Table of Tables ......................................................................................................... vi List of Abbreviations ................................................................................................ viii Acknowledgements .................................................................................................... x Abstract ..................................................................................................................... xi Chapter 1. Literature Review ..................................................................................... 1 Importance and quantification of feed efficiency ..................................................... 1 Residual feed intake (RFI) ...................................................................................... 2 Biological factors that contribute to the variation in feed efficiency ......................... 4 Digestibility, amino acids and energy nutrition ..................................................... 5 Body composition ................................................................................................ 8 Protein turnover ................................................................................................. 10 Metabolism and oxidative stress ........................................................................ 13 Feeding pattern and physical activity ................................................................. 16 Conclusions .......................................................................................................... 17 Literature Cited ..................................................................................................... 18 Chapter 2. Improved nutrient and energy digestibility and retention partially explains feed efficiency gains in pigs selected for low residual feed intake ....... 25 Abstract ................................................................................................................. 25 Introduction ........................................................................................................... 26 iii Materials and Methods .......................................................................................... 27 Experimental Design ......................................................................................... 27 Performance Traits ............................................................................................ 28 Nutrient Digestibility and Retention .................................................................... 28 Disaccharide and L-Alanine Aminopeptidase Activities ..................................... 31 Statistical Analyses ............................................................................................ 32 Results .................................................................................................................. 32 Discussion ............................................................................................................. 34 Literature Cited ..................................................................................................... 38 Chapter 3. Whole body composition and tissue accretion rates differ in gilts divergently selected for residual feed intake ...................................................... 47 Abstract ................................................................................................................. 47 Introduction ........................................................................................................... 48 Materials and Methods .......................................................................................... 49 Experimental Design ......................................................................................... 49 Performance Traits ............................................................................................ 50 Body Composition ............................................................................................. 51 Statistical Analyses ............................................................................................ 52 Results .................................................................................................................. 54 Discussion ............................................................................................................. 57 Literature Cited ..................................................................................................... 63 Chapter 4. General Discussion ............................................................................... 76 Literature Cited ..................................................................................................... 82 iv Appendix .................................................................................................................. 84 Short Research Paper ........................................................................................... 84 Improved nutrient digestibility and retention partially explains feed efficiency gains in pigs selected for low residual feed intake ............................................. 84 Abstracts ............................................................................................................... 92 Effects of heat stress on Na+/K+ATPase activity in growing pigs ...................... 92 Effects of heat stress on energetic metabolism in growing pigs ........................ 93 Reactive oxygen species production in mitochondria of pigs selected for residual feed intake ........................................................................................... 94 Protein profile in mitochondria of pigs selected for residual feed intake ............ 95 The effects of immune stressors on porcine intestinal epithelial cell integrity and inflammation ............................................................................................... 96 The physiological basis defining feed efficiency differences in pigs selected on residual feed intake....................................................................................... 97 Gilts selected for low residual feed intake have potential for decreased protein degradation ............................................................................................ 98 v Table of Figures Figure 1.1. Time trends of feed conversion ratio in grower-finisher pigs .............. 1 Figure 1.2. Contributions of biological mechanisms to variation in residual feed intake .................................................................................................... 4 Figure 1.3. Traditional view of energy systems .................................................... 5 Figure 1.4. Typical whole body protein deposition curves in barrows, gilts and entire male pigs ............................................................................................. 7 Figure 1.5. Schematic representation of the ubiquitin-proteasome pathway ..... 11 Figure 1.6. Model of mTOR-raptor interaction with mitochondria ...................... 12 Figure 1.7. Sodium-potassium pumps ............................................................... 14 Figure 1.8. Schematic representation of the respiratory chain ........................... 15 Figure 3.1. The effects of divergent selection for low (LRFI) and high (HRFI) residual feed intake on whole body tissue and energy accretion in finisher gilts ................................................................................................. 73 Figure 4.1. Physiology underlying the low residual feed intake phenotype ........ 83 vi Table of Tables Table 2.1. Ingredients and chemical composition of the diet (as-fed basis) ............. 42 Table 2.2. Effects of selection for residual feed intake (RFI) on growth performance