University of Kentucky UKnowledge Theses and Dissertations--Animal and Food Sciences Animal and Food Sciences 2019 FORMS OF SUPPLEMENTAL SELENIUM IN VITAMIN-MINERAL MIXES DIFFERENTIALLY AFFECT SEROLOGICAL AND HEPATIC PARAMETERS OF GROWING BEEF STEERS GRAZING ENDOPHYTE-INFECTED TALL FESCUE Yang Jia University of Kentucky, [email protected] Digital Object Identifier: https://doi.org/10.13023/etd.2019.028 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Jia, Yang, "FORMS OF SUPPLEMENTAL SELENIUM IN VITAMIN-MINERAL MIXES DIFFERENTIALLY AFFECT SEROLOGICAL AND HEPATIC PARAMETERS OF GROWING BEEF STEERS GRAZING ENDOPHYTE- INFECTED TALL FESCUE" (2019). Theses and Dissertations--Animal and Food Sciences. 97. https://uknowledge.uky.edu/animalsci_etds/97 This Doctoral Dissertation is brought to you for free and open access by the Animal and Food Sciences at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Animal and Food Sciences by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained needed written permission statement(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine) which will be submitted to UKnowledge as Additional File. I hereby grant to The University of Kentucky and its agents the irrevocable, non-exclusive, and royalty-free license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless an embargo applies. I retain all other ownership rights to the copyright of my work. I also retain the right to use in future works (such as articles or books) all or part of my work. I understand that I am free to register the copyright to my work. REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s thesis including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Yang Jia, Student Dr. James C. Matthews, Major Professor Dr. David L. Harmon, Director of Graduate Studies FORMS OF SUPPLEMENTAL SELENIUM IN VITAMIN-MINERAL MIXES DIFFERENTIALLY AFFECT SEROLOGICAL AND HEPATIC PARAMETERS OF GROWING BEEF STEERS GRAZING ENDOPHYTE-INFECTED TALL FESCUE ________________________________________ DISSERTATION ________________________________________ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Agriculture, Food and Environment at the University of Kentucky By Yang Jia Lexington, Kentucky Director: Dr. James C. Matthews, Professor of Animal and Food Sciences Lexington, Kentucky 2019 Copyright © Yang Jia 2019 ABSTRACT OF DISSERTATION FORMS OF SUPPLEMENTAL SELENIUM IN VITAMIN-MINERAL MIXES DIFFERENTIALLY AFFECT SEROLOGICAL AND HEPATIC PARAMETERS OF GROWING BEEF STEERS GRAZING ENDOPHYTE-INFECTED TALL FESCUE Consumption of endophyte-infected tall fescue results in a syndrome of negatively altered physiological systems, collectively known as fescue toxicosis. Another challenge to endophyte-infected tall fescue -based beef cattle operations is that the soils often are selenium (Se) poor, necessitating the need to provide supplemental Se. To test the general hypothesis that different forms of supplemental Se would ameliorate the negative effects of fescue toxicosis, predominately-Angus steers (BW = 183 ± 34 kg) were randomly selected from herds of fall-calving cows grazing an endophyte-infected tall fescue pasture and consuming vitamin-mineral mixes that contained 35 ppm Se as sodium selenite (ISe), SELPLEX (OSe), or an 1:1 blend of ISe and OSe (MIX). Steers were commonly weaned and depleted of Se for 98 d. Steers were assigned (n = 8 per treatment) to the same Se-form treatments upon which they were raised and subjected to summer-long common grazing of an endophyte-infected tall fescue pasture (0.51 ppm ergot alkaloids: ergovaline plus ergovalinine; 10.1 ha). Selenium treatments were administered by daily top-dressing 85 g of vitamin-mineral mix onto 0.23 kg soyhulls, using in-pasture Calan gates. The first project objective was to determine the effect of forms of supplemental Se on whole blood Se, serum prolactin, liver glutamine synthetase (GS) activity, carcass parameters, and growth performance (Experiment 1). In Experiment 1, whole blood Se increased for all treatments from day 0 to 22 and then did not change. Across periods, MIX and OSe steers had greater whole blood Se than ISe steer. Compared to ISe steers, MIX and OSe steers had more serum prolactin. Liver GS mRNA, protein content, and activity were greater in MIX and OSe steers than ISe steers. However, the ADG and carcass parameters were not affected by Se treatments. The second project objective was to determine the effect of forms of supplemental Se on serum clinical parameters of Experiment 1 steers (Experiment 2). In Experiment 2, across periods, MIX steers had more serum albumin than OSe, and ISe steers, respectively. Serum alkaline phosphatase (ALP) activity was greater in MIX and OSe steers. In addition, blood urea nitrogen (BUN), serum sodium, phosphorus, and magnesium concentration were affected by Se treatments. Partial correlation analysis revealed that serum albumin, BUN, and ALP activity were correlated with whole blood Se concentration. The third project objective was to evaluate the hepatic transcriptome profiles of Experiment 1 steers using microarray and targeted RT-PCR analyses (Experiment 3). In Experiment 3, bioinformatic analysis of microarray data indicated that hepatic glutamate/glutamine, proline, arginine, and citrulline metabolism was affected by different forms of supplemental Se. The mRNA expression of critical proteins involved in glutamate/glutamine (GLS2, GLUD1, GLUL), proline (PYCR1, ALDH18A1), and urea (ARG1, ARG2, OAT, NAGS, OTC, ORNT1) metabolism were differentially expressed by Se treatments. Collectively, we conclude that consumption of 3 mg Se/d as OSe or MIX forms of Se in vitamin-mineral mixes 1) increased whole blood Se content, an indicator of greater whole-body Se assimilation; 2) increased serum prolactin, albumin, and ALP, the reduction of which are hallmarks of fescue toxicosis; and 3) altered hepatic nitrogen metabolism, as indicated by changes in key enzymes of glutamate/glutamine, proline, and urea metabolism. However, 4) these positive effects on metabolic parameters were not accompanied by increased growth performance. KEYWORDS: Fescue toxicosis, Selenium supplementation, Prolactin, Alkaline phosphatase, Glutamine synthetase Yang Jia (Name of Student) 3/11/2019 Date FORMS OF SUPPLEMENTAL SELENIUM IN VITAMIN-MINERAL MIXES DIFFERENTIALLY AFFECT SEROLOGICAL AND HEPATIC PARAMETERS OF GROWING BEEF STEERS GRAZING ENDOPHYTE- INFECTED TALL FESCUE By Yang Jia Dr. James C. Matthews Director of Dissertation Dr. David L. Harmon Director of Graduate Studies 3/11/2019 Date ACKNOWLEDGEMENTS I would like to extend my sincere appreciations and best wishes to all the people who I benefited from in the process of completing this dissertation. First of all, I would like to express my deepest gratitude to my major professor, Dr. James C. Matthews, for his intellectual guidance, constructive suggestions, and patience throughout my graduate career. Words cannot justify my appreciations to your support and inspirations as a mentor, as well as a scientist. These experience working with you makes me a better student, scientist, and man. Next, my grateful appreciations also extend to Dr. Amanda A. Adams, Dr. Phillip J. Bridges, Dr. James L. Klotz, and Dr. Karen J. McDowell for serving on the advisory committee, and to Dr. Bin-Tao Pan for serving as an outside examiner. I am really grateful about each individual for providing valuable insights, guiding and challenging my thinking during every stage of the dissertation process. Moreover, I also want to extend my gratitude to the support and help from other professors of the beef nutrition group, Dr. Walter R. Burris, who provides critical guidance and support on the animal management part of the dissertation. I would like to thank all the help and support through the years from Dr. David L. Harmon, Dr. Eric S. Vansant, and Dr. Kyle R. McLeod. Next, I would like to appreciate Mr. Kwangwon Son, Mr. Hugo Hamilton, and Mrs. Susan Hayes for their technical and instrumental support on laboratory assays and sample analysis. Appreciation is also extended to Mrs. Blair Knight and the crew in UKREC, Princeton for their countless assistance and management on the beef steers used in the dissertation. My sincere gratitude is also extended to Qing Li, Jing Huang, Alex Altman, and Ning Lu for their help and friendship. Last but not least, I am always thankful for my parents and family for their unconditional love and support to me. No matter what I do and where I go, their iii blessings have always