Incubation Temperature Effects on Broiler Chicken Embryos
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INCUBATION TEMPERATURE EFFECTS ON BROILER CHICKEN EMBRYOS by KATIE ELAINE COLLINS (Under the Direction of Jeanna L. Wilson) ABSTRACT Extreme variations in incubation temperature affect the broiler embryo and, ultimately, post hatch broiler performance. Previous studies have implied that incubation temperature may impact chick quality and sex of the chick. The control of both parameters would be economically beneficial to the poultry industry. This work evaluated embryonic differences between a modern high yielding broiler and a 1950s meat-type chicken strain when incubated at a 1950s incubation temperature (37.7°C) and investigated incubation temperature effects on modern broiler sex ratios. These data suggest that the incubation temperature of 50 years ago is too high for the modern broiler. Wide temperature variations (0.8°C) away from standard temperature were not found to influence the sex ratio of broiler chicks at hatch. INDEX WORDS: broiler, incubation temperature, sex, Athens Canadian Random Bred INCUBATION TEMPERATURE EFFECTS ON BROILER CHICKEN EMBRYOS by KATIE ELAINE COLLINS B.S.A., The University of Georgia, 2011 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2013 © 2013 Katie Elaine Collins All Rights Reserved INCUBATION TEMPERATURE EFFECTS ON BROILER CHICKEN EMBRYOS by KATIE ELAINE COLLINS Major Professor: Jeanna L. Wilson Committee: R. Jeff Buhr Kristen J. Navara Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia May 2013 DEDICATION This Thesis is dedicated in honor of my father, Dr. Gearl Martin “Marty” Collins, Jr. and to Abigail, my first chicken. iv ACKNOWLEDGEMENTS I am thankful to Dr. Jeanna Wilson for her mentorship on these projects. I feel that I have learned much under her direction. Thanks to Dr. R. Jeff Buhr and Dr. Kristen Navara for their help and critiques on this Thesis. I am thankful to the Poultry Science Department in particular Dr. Mike Lacy and Dr. Brian Fairchild for their advice and the opportunities to participate in extension activities. I am grateful for Beverly McLendon’s help, and Jesse Hanks’ maintenance on the NatureForm incubators. I have appreciated Dean Christian’s and John Beauchamp’s assistance and company. I wish to express appreciation to my mother and brother for their support, and to my dachshund, Buster, for his reminders of mealtime. v TABLE OF CONTENTS Page ACKNOWLEDGEMENTS .............................................................................................................v LIST OF TABLES ....................................................................................................................... viii LIST OF FIGURES ....................................................................................................................... ix CHAPTER 1 INTRODUCTION .........................................................................................................1 2 LITERATURE REVIEW ..............................................................................................3 Artificial Incubation for Poultry ..............................................................................3 Incubation Temperature ...........................................................................................6 Strain Differences in Embryonic Development .....................................................16 Sex Differences in Embryonic Development ........................................................19 Sex Determination and Differentiation ..................................................................21 Bird Incubation Temperature Sex Ratio Investigations .........................................23 Literature Review Summary ..................................................................................28 References ..............................................................................................................29 3 HATCHABILITY AND EMBRYONIC DEVELOPMENT OF ATHENS CANADIAN RANDOM BRED BROILERS AND THE MODERN HIGH YIELDING BROILER ................................................................................................40 Abstract ..................................................................................................................41 Introduction ............................................................................................................42 vi Materials and Methods ...........................................................................................43 Results ....................................................................................................................49 Discussion ..............................................................................................................53 References ..............................................................................................................60 4 NO EVIDENCE OF TEMPERATURE-DEPENDENT SEX DETERMINATION OR SEX-BAISED EMBRYO MORTALITY IN THE CHICKEN ...................................86 Abstract ..................................................................................................................87 Introduction ............................................................................................................88 Materials and Methods ...........................................................................................90 Results ....................................................................................................................94 Discussion ..............................................................................................................97 References ............................................................................................................100 5 CONCLUSIONS........................................................................................................109 APPENDICES A RECORDING EGGSHELL TEMPERATURE ........................................................112 B HISTORY OF THE ATHENS CANADIAN RANDOM BRED CONTROL POPULATION ............................................................................................................................117 vii LIST OF TABLES Page Table 3.1: Average Egg Measurements .........................................................................................71 Table 3.2: Average Embryonic Heart Weight ...............................................................................72 Table 3.3: Average Percentage Embryonic Heart ..........................................................................73 Table 3.4: Average Embryo Intestine Weight ...............................................................................74 Table 3.5: Average Percentage Embryo Intestine ..........................................................................75 Table 3.6: Average Natural Curled Embryo Diameter Length ......................................................76 Table 3.7: Average Stretched Embryo Length ..............................................................................77 Table 3.8: Average Embryo Wing Length .....................................................................................78 Table 3.9: Average Embryo Leg Length .......................................................................................79 Table 3.10: Average Embryo Third Toe Without the Nail Length................................................80 Table 3.11: Average Embryo Third Toe With the Nail Length .....................................................81 Table 3.12: Average Embryo Beak Length ...................................................................................82 Table 3.13: Average Embryo Third Toe Nail Length....................................................................83 Table 3.14: Average Hamburger and Hamilton Embryo Stages ...................................................84 Table 3.15: Residue Egg Analysis .................................................................................................85 Table 4.1: Single Stage Set Incubation Temperatures .................................................................107 Table 4.2: Male Broiler Percentages Based on Incubation Temperature ....................................108 viii LIST OF FIGURES Page Figure 3.1: Demonstration of Natural Curled Embryo Diameter Length Measurement ...............64 Figure 3.2: Average Athens Canadian Random Bred and Cobb 500 Embryo Weights ................65 Figure 3.3: Average Athens Canadian Random Bred and Cobb 500 Embryo Weights as a Percentage of Initial Egg Weight .......................................................................................66 Figure 3.4: Average Eggshell Temperatures of Athens Canadian Random Bred and Cobb 500 ..67 Figure 3.5: Cumulative Percent Hatch Recorded Every 6 Hours from 468-498 Hours of Incubation in Two Trials Comparing the Athens Canadian Random Bred and the Cobb 500 broiler ..........................................................................................................................68 Figure 3.6: Average Air Temperatures in the Incubator by Location ............................................69 Figure 3.7: Average Air Temperatures in the Hatcher ..................................................................70 Figure 4.1: Trial 1 Average Eggshell Temperatures ....................................................................103 Figure 4.2: Trial 2 Average Eggshell Temperatures ....................................................................104