University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Theses and Dissertations in Animal Science Animal Science Department 5-2020 Impact of Diet and Quality Grade on Meat Quality Characteristics and Their Relationship to Oxidative Stress Nicolas Bland University of Nebraska - Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/animalscidiss Part of the Agriculture Commons, and the Animal Sciences Commons Bland, Nicolas, "Impact of Diet and Quality Grade on Meat Quality Characteristics and Their Relationship to Oxidative Stress" (2020). Theses and Dissertations in Animal Science. 197. https://digitalcommons.unl.edu/animalscidiss/197 This Article is brought to you for free and open access by the Animal Science Department at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Theses and Dissertations in Animal Science by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Impact of Diet and Quality Grade on Meat Quality Characteristics and Their Relationship to Oxidative Stress by Nicolas A. Bland A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science Major: Animal Science Under the Supervision of Professor Chris R. Calkins Lincoln, Nebraska May, 2020 Impact of Diet and Quality Grade on Meat Quality Characteristics and Their Relationship to Oxidative Stress Nicolas A. Bland, M.S. University of Nebraska, 2020 Advisor: Chris R. Calkins Marbling and tenderness in meat are some of the most impactful factors for the consumer eating experience. The cause of the relationship between marbling and tenderness is still unresolved. This study was conducted to evaluate the effects of feeding different types of processed corn, with or without distiller grains on oxidative stress, and how that relates to tenderness and shelf life of beef steaks of differing quality grades. Steers (n= 240) were finished on dry rolled corn (DRC), DRC + 30% dried distillers grains (DDGS), steam flaked corn (SFC), or SFC + 30% DDGS. Cattle were fed 10 per pen. Only pens with both upper 2/3 Choice and Select-grade carcasses were sampled, with a goal of two (and a minimum of one) of each grade per pen. Three pens per treatment met the selection criterion and 36 carcasses were chosen (21 upper 2/3 Choice and 15 Select). Both strip loins were collected from each carcass, halved, and aged for 2, 9, 16, or 23 d. After aging, steaks were placed under retail display for 7 d. Subjective discoloration and instrumental color (L*, a*, and b*) were determined daily, and Warner- Bratzler shear force (WBSF), slice shear force (SSF), and lipid oxidation (thiobarbituric acid reactive substances; TBARS), were measured after 0 and 7 d of retail display. Fatty acid profile, proximate composition, sarcomere length, sarcoplasmic calcium, pH, proteomic analysis, isoprostane content, and troponin-T (Tn-T) degradation of the lean were obtained. No impacts on sarcomere length, pH, sarcoplasmic calcium, and isoprostane content were found ( P> 0.05). The difference in proximate composition was due to fat content between quality grades ( P< 0.05). As aging continued, increases in tenderness, degradation of Tn-T, percent discoloration, and lipid oxidation were found, along with a decrease of redness values (P< 0.05). Increases in objective tenderness, discoloration, and decreases in color stability of retail display occurred from 5 to 7 d (P< 0.05). Steaks from cattle fed DRC (compared to SFC) and without DDGS (compared to with DDGS) were statistically lower for discoloration, and C18:2 (linoleic acid) and higher in redness and TBARS values (P< 0.05). Proteomic data revealed greater oxidation of proteins related to tenderness in Upper 2/3 Choice-grade steaks than Select-grade steaks and in steaks from cattle fed DRC+DDGS than steaks from cattle fed DRC. Steaks from cattle fed DRC were more tender than steaks from cattle fed SFC and Upper 2/3 Choice-grade steaks were more tender and have greater oxidative damage in the proteins than Select-grade steaks. iv ACKNOWLEDGMENTS The completion of my graduate degree would not have been possible without the support, advice, and direction of numerous people. Therefore, I would like to show my genuine gratitude to those that, even in minute ways, helped make this achievement a reality. Primarily, I would earnestly like to thank my major advisor, Dr. Chris Calkins, for accepting me as one of his students. A clear example that exhibits enthusiasm, dedication, wisdom, and knowledge, Dr. Calkins developed a graduate program that stretched and developed me as a meat scientist, a professional, and individual. Pulling on a wealth of experience, Dr. Calkins showed both an uncommon degree of patience for me in my shortcomings and encouraged me to continually improve beyond my successes. His drive for knowledge, excellence, and professionalism has been in many ways inspirational and instructive in my years here. Thank you for this opportunity to observe, learn, and adapt in the field of science I enjoy. To my committee members, Dr. Gary Sullivan and Dr. Dennis Burson - thank you for being another body of knowledge and direction for my time here. My considerable amount of time interacting with Dr. Sullivan has been enlightening both intellectually and philosophically, but also entertaining. In an environment of perpetual expectation of professionalism, Dr. Sullivan’s willingness to often and jovially interact with me in a candid, informative, and variable manner has been refreshing, engaging, and edifying. I would also like to thank Dr. Steve Jones for providing an educational experience as a teaching assistant for one of his courses. Overall, I will have positive memories interacting with these professors and count myself fortunate for the experiences. v Completion of this program would not have been conceivable without the assistance of the meat science staff. Tommi Jones is an ever-patient source of experience and guidance in the lab when it comes to preparing and executing both the inception of lab projects and lab analyses. Her patience with me and the busy world of the research lab has been both humbling and encouraging to witness. Sherri Pitchie is the plucky cornerstone that progresses the meats group beyond the science in a meaningful way. An interesting balance of support, wisdom, and candor Sherri can too easily be overlooked for providing both emotional stability for the graduate students and the quiet completion of tasks critical for the office to progress efficiently. Like the other members of the meats science staff, Calvin Schrock is instrumental to the smooth efficiency of his domain, ‘the meat lab.’ I will always appreciate Calvin’s willingness to forgive inexperience during slaughter, fabrication, and production, and seemingly be more interested in teaching to improve our handling of meat product. Lastly, thanks to Anjeza Erickson, Dr. Camila Braga, and Dr. Michael Chao for his or her helpfulness in collecting data through a variety of protocols. A special thanks goes out to the fellow graduate students that I have had the interesting opportunity of becoming friends with during the past two and a half years: Felipe “Bro” Ribeiro, Kellen Hart, Morgan Henriott, Nicolas Herrera, Becca Furbeck, Joe Sonderman, David Velazco, Sam Watson, Chad Bower, Lauren Kett, Jessica Lancaster, and Faith Rasmussen. I will cherish the friendships, nonsensical conversations, and great memories from the last few years. I appreciate the patience with my unique sense of humor and often chaotic actions done in good fun and to raise the group’s morale. Whether playing cards games, going downtown, camping, discussing science or politics, or viewing comedic videos, there was always laughter to be had and opportunities to mature. vi Finally, I would like to show my gratitude to my family and friends that supported me from afar. Although difficult at times, I appreciate the support you always gave me, despite your troubles. In difficult times, I recognize it is hard to look past your own challenges and still try to encourage and support me, despite the distance. I will take these experiences and use them to further grow and try to become a better man. In this and the multitude of things I intend to do, I hope I can always honor my grandfather’s hopes for me. I’m thankful for the friendships garnered back at home and while at Purdue which have been refreshing and welcomed respites from my troubles and another support system. My time at the University of Nebraska has been a greater learning experience than I could have ever realized, with lessons I intend to incorporate and develop in the time to come. Thank you to The Beef Checkoff for partially funding this research. “Strive not to be a success, but rather to be of value.” Albert Einstein vii TABLE OF CONTENTS TITLE PAGE………………………………………………………………………………………i ABSTRACT………………………………………………………………………………………ii ACKNOWLEDGEMENTS………………………………………………………………………iv TABLE OF CONTENTS………………………………………………………………………..vii INTRODUCTION………………………………………………………………………………...1 LITERATURE REVIEW……………………………………………………………….………...3 Defining Oxidative Stress…………………………………………….…………………………...3 Factors that Relate to Oxidative Stress.…………………………………………………………...9 Genetics…………………………………………………………….……………………...9 Lipid oxidation & Stability of the Sarcoplasmic Reticulum (SR) ………………………11 Diet……………………………………………………………………………………….14 DNA