PALOMA DE MELO AMARAL PERFORMANCE AND AMINO ACIDS REQUIREMENTS OF NELLORE AND CROSSBRED ANGUS×NELLORE FED DIETS WITH DIFFERENT CRUDE PROTEIN CONTENT DURING GROWING AND FINISHING STAGES Thesis submitted to the Universidade Federal de Viçosa as partial fulfillment of the requirements of the Graduate Program in Animal Science to obtain the degree of Doctor Scientiae. VIÇOSA MINAS GERAIS – BRASIL 2016 ii PALOMA DE MELO AMARAL PERFORMANCE AND AMINO ACIDS REQUIREMENTS OF NELLORE AND CROSSBRED ANGUS×NELLORE FED DIETS WITH DIFFERENT CRUDE PROTEIN CONTENT DURING GROWING AND FINISHING STAGES Thesis submitted to the Universidade Federal de Viçosa as partial fulfillment of the requirements of the Graduate Program in Animal Science to obtain the degree of Doctor Scientiae. APPROVED: September 23, 2016 _______________________________ _______________________________ EdenioDetmann Mário Luiz Chizzotti (Co-adviser) (Co-adviser) _______________________________ _______________________________ Stefanie Alvarenga Santos Antonio Pinheiro Faciola _______________________________ Sebastião de Campos Valadares Filho (Adviser) iii To my parents, for dedication, love and encouragement. You are my safe haven. To my sister, forgiving me the strength to move on, regardless of the difficulties. To Guilherme and Duda, my support, happiness and strength! To my "mommy" Lili, for the principles and values taught, now make me who I am. To my godfather, for all the support, love and attention. To my relatives, for always being by my side, giving me support and love. I dedicate. ii ACKNOWLEDGEMENT I would like to start thanking God for the strength to keep going and never give up, and for putting incredible people in my way! My thesis would not have been possible without the help of many people. I cannot express how thankful I am for the love and support I received from my parents, siblings, family and friends. I would like to thank my parents who always supported me throughout my academic career, as well as everything I have achieved in life. Without their love and support I would not be the person I am today. My siblings and relatives for their love, encouragement and support in the most difficult moments. My nephews and nieces, to bring happiness to my heart. To Lays “carminha”, my sister by choice (or not). Thank you for becoming more than an experiment colleague. You were a great gift in my life. To Laura “Piri”, your friendship and support were essential during this trajectory.I have no words to thank you all you ever done for me. To Carol, for all the years of friendship and for giving me a handand a ceiling when I most needed. I will be forever grateful. To Maria Eduarda, for your patience and encouragement during the last amazing year. Thank you for staying by my side through the ups and downs and being there to cheer me up! You truly are my person. To Luxos, for your friendship, patience and advice, Thanks for the great contribution in this work and in my professional growth. To Claudinha, for putting me on the shaft, "tied" in her office. To the Animal Science Department at the Universidade Federal de Viçosa, for 10 years of training. To CNPq, INCT-CA, CAPES and FAPEMIG for providing the financial support of this research and granting scholarships. A big thank also needs to be given to myadviser Dr. Sebastião de Campos Valadares Filho, for the opportunities and guidance. Thank you for your patience and for trusting me and giving me support during tough moments. iii To Dr. Marcos Marcondes, for your hard-work and indispensable help in the completion of this work. You have believed in me and since then, I have been able to do things I never thought possible of myself. My eternal gratitude and friendship. To Dr.MarioChizzotti, for being an example since freshman year. Members of my committee, Dra. Stefanie Alvarenga, Dr. Marcos Marcondes, Dr. EdenioDetmann, Dr. Mario Chizzotti,Dr. AntonioFaciola, Dra. Luciana Rennó. You provided invaluable assistance in the completion of my thesis. Dr. Faciola, for all advice and words of encouragement. A big thank you for the amazing experience in USA. I am very grateful for the opportunity to have been part of an amazing group, which works as a team. The “family of ants”: Lyvian, Danilo, Jarbinha, Marcelo Grossi, “Uncle Jojo” and Zeze. Friends, interns and undergraduate research fellows, which were essential and allowed the realization and completion of this work: Marquinhos, Jessiquinha, Maysinha, Letícia (Letlet), Ana, Flavão, Jayminho, Pedro, Lucas, Luciano, Breno, Letícia, Pum e Niel. My dear friends: Lays, Laura, Luxos, Pedrão, Luciana, Fabi Lana, Aline (Sinha), Erick, Jarbas, Leandrão, (…)for the friendship, help, encouragement, studies and special moments. To my family by choice: Tainnah, Paulo, Quequé, Pedrão, Allan, Théo, Cefet, Isadora, Aline, Claudinha. Employees of DZO, especially Vanor, Zeze, Pum, TiJojo, Marcelo Cardoso, Niel, Seu Jorge, Venancio, Edinho and Monteiro, for their support, cooperation, friendship. Plinio, Seu Mario and Fernando, for help in the analysis. Especially Fernandinha, for your patience, help and “mother love” and Aldinha for the affection and the company during coffee break time. To my Nevada friends, Lorrayny, Eduardinho, Gus, menino Hugo, meninaJéssica, Hélio, Genila, Vevê, Beth, Marisa, little Jack and princess Emilly. You have made my experience in Reno unforgettable and ultra-especial. Finally, I would like to thank everyone who somehow contributed to the realization of this work and cheered for me. I appreciate all that each one of you have done for me. iv “Strength doesn’t come from what you can do. It comes from overcoming the things you once thought you couldn’t.” Rikki Rogers v BIOGRAPHY Paloma de Melo Amaral, daughter of José Abílio Lopes Amaral and Maria José de Melo Amaral, was born in Rio de Janeiro/RJ-Brazil on Feb 24, 1986. Started the undergraduate in Animal Science at Universidade Federal de Viçosa in 2005 and became a Bachelor in Animal Science in 2010. At the same year, she started the Magister Scientiae program in Ruminant Nutrition with major emphasis in Beef cattle. In February of 2010, she became a Master in Animal Science. At the same year, she started her PhD program in Animal science in the same area of Master. From Novembre of 2014 to August of 2015, she was a visiting research at University of Nevada – Reno/NV-USA, where part of her research was developed. On September of 2016, Paloma de Melo Amaral submitted her thesis to the committee to obtain the Doctor Scientiae degree in Animal Science. vi LIST OF CONTENTS ABSTRACT ............................................................................................................................................... ix RESUMO ............................................................................................................................................... xiii GENERAL INTRODUCTION ....................................................................................................................... 1 LITERATURE CITED .................................................................................................................................. 5 CHAPTER 1 .............................................................................................................................................. 7 Do dietary protein content and genetic group affect performance, feed efficiency and carcass traits of beef cattle at different stages of feedlot? .......................................................................................... 7 Abstract ................................................................................................................................................... 7 Introduction ............................................................................................................................................. 8 Materials and methods ............................................................................................................................ 9 Animals and Experimental Design ...................................................................................................... 9 Sample processing ............................................................................................................................ 10 Chemical analysis .............................................................................................................................. 11 Carcass evaluation ............................................................................................................................ 12 Statistical analysis ............................................................................................................................. 13 Results ................................................................................................................................................... 13 Discussion ............................................................................................................................................. 17 Literature Cited ..................................................................................................................................... 22 CHAPTER 2 ............................................................................................................................................ 30 Amino acids requirements of Nellore and crossbred A×N fed different crude protein content...... 30 Abstract ................................................................................................................................................. 30 Introduction ........................................................................................................................................... 31 Materials and methods .......................................................................................................................... 33 Animals and Experimental Design .................................................................................................... 33 Carcass evaluation ............................................................................................................................ 34 Chemical analysis .............................................................................................................................. 35 Net Requirements of Amino Acids for gain ...................................................................................... 35 Statistical analysis ............................................................................................................................. 36 Results and discussion .......................................................................................................................... 36 Conclusion ............................................................................................................................................ 40 Literature Cited ..................................................................................................................................... 41 Capítulo 3 .............................................................................................................................................. 54 vii Exigências de energia e proteína de zebuínos puros (Nelore) e cruzados (F1 Angus x Nelore) não castrados em confinamento ............................................................................................................... 54 Resumo ................................................................................................................................................. 54 Introdução ............................................................................................................................................. 55 Material e Métodos ............................................................................................................................... 58 Manejo animal, delineamento experimental e dietas ...................................................................... 58 Amostragens dos alimentos e das sobras ......................................................................................... 60 Mensurações na Câmara Respirométrica ......................................................................................... 61 Ensaio de digestibilidade .................................................................................................................. 62 Abates e amostragens ....................................................................................................................... 63 Análises químicas .............................................................................................................................. 65 Cálculos para as exigências nutricionais e análises estatísticas ........................................................ 66 Resultados e discussão .......................................................................................................................... 68 Conclusão .............................................................................................................................................. 78 Referências ............................................................................................................................................ 79 viii