University of Kentucky UKnowledge Theses and Dissertations--Animal and Food Sciences Animal and Food Sciences 2019 RESPONSES OF BOVINE PITUITARY TRANSCRIPTOME PROFILES TO CONSUMPTION OF TOXIC TALL FESCUE AND FORMS OF SELENIUM IN VITAMIN-MINERAL MIXES Qing Li University of Kentucky, [email protected] Digital Object Identifier: https://doi.org/10.13023/etd.2019.035 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Li, Qing, "RESPONSES OF BOVINE PITUITARY TRANSCRIPTOME PROFILES TO CONSUMPTION OF TOXIC TALL FESCUE AND FORMS OF SELENIUM IN VITAMIN-MINERAL MIXES" (2019). Theses and Dissertations--Animal and Food Sciences. 99. https://uknowledge.uky.edu/animalsci_etds/99 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. Qing Li, Student Dr. James C. Matthews, Major Professor Dr. David L. Harmon, Director of Graduate Studies RESPONSES OF BOVINE PITUITARY TRANSCRIPTOME PROFILES TO CONSUMPTION OF TOXIC TALL FESCUE AND FORMS OF SELENIUM IN VITAMIN-MINERAL MIXES ________________________________________ 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 Qing Li Lexington, Kentucky Director: Dr. James C. Matthews, Professor of Animal and Food Sciences Lexington, Kentucky 2019 Copyright © Qing Li 2019 ABSTRACT OF DISSERTATION RESPONSES OF BOVINE PITUITARY TRANSCRIPTOME PROFILES TO CONSUMPTION OF TOXIC TALL FESCUE AND FORMS OF SELENIUM IN VITAMIN-MINERAL MIXES The first goal of the current research was to determine whether gene expression profiles differed between whole pituitaries of growing beef steers grazing pastures containing high (HE) or low (LE) amounts of toxic endophyte-infected tall fescue. The global (microarray analysis) and selected targeted (RT-PCR) mRNA expression patterns of pituitaries collected from beef steers (BW = 266 ± 15.5 kg) that had been randomly assigned to undergo summer-long grazing (89 to 105 d) of either HE (0.52 ppm ergot alkaloids) or LE (< 0.03 ppm ergot alkaloids) pastures were compared. Gene expression data were subjected to one-way ANOVA. The pituitaries of HE steers had 542 differentially expressed genes, and the pattern of altered gene expression was dependent on treatment. Targeted RT-PCR analysis corroborated these findings, including decreased expression of DRD2, PRL, POU1F1, GAL, and VIP and that of POMC and PCSK1, respectively. Canonical pathway analysis (Integrated Pathway Analysis, IPA) identified HE-dependent alteration in signaling of additional pituitary-derived hormones, including growth hormone and GnRH. In conclusion, consumption of endophyte-infected tall fescue alters the pituitary transcriptome profiles of steers in a manner consistent with their negatively affected physiological parameters. The second goal of this project was to test the hypothesis that sodium selenite (ISe), SEL-PLEX (OSe), vs. a 1:1 blend (MIX) of ISe and OSe in a basal vitamin-mineral (VM) mix would differentially alter pituitary transcriptome profiles in growing beef steers (BW = 183 ± 34 kg) commonly grazing an endophyte-infected tall fescue (HE) pasture. Steers were randomly selected from herds of fall-calving cows grazing HE pasture and consuming VM mixes that contained 35 ppm Se as either ISe, OSe, or MIX forms. Steers were weaned, depleted of Se for 98 d, and subjected to summer-long common grazing of a 10.1 ha HE pasture containing 0.51 ppm ergot alkaloids. Steers were assigned (n = 8) to the same Se-form treatments on which they were raised. Selenium treatments were administered by daily top-dressing 85 g of VM mix onto 0.23 kg soyhulls, using in-pasture Calan gates. Pituitaries were collected at slaughter and changes in global (microarray) and selected (RT-PCR) mRNA expression patterns determined. The effects of Se treatment on relative gene expression were subjected to one- way ANOVA. The form of Se affected the expression of 542 annotated genes. Integrated Pathway Analysis found a canonical pathway network between prolactin and POMC/ACTH/ α-MSH synthesis-related proteins, and that mitochondrial dysfunction was a top-affected canonical pathway. Targeted RT-PCR analysis found that the relative abundance of mRNA encoding prolactin and POMC/ACTH/ α-MSH synthesis-related proteins was affected by the form of Se, as were mitochondrial dysfunction-related proteins OSe steers appeared to have a greater prolactin synthesis capacity vs. ISe steers through decreased dopamine receptor D2 signaling, whereas MIX steers had a greater prolactin synthesis capacity and release potential by increasing TRH concentrations than ISe steers. OSe steers also had a greater ACTH and α-MSH synthesis potential than ISe steers. We conclude that form of Se in VM mixes affected genes responsible for prolactin and POMC/ACTH/α-MSH synthesis, and mitochondrial function in pituitaries of growing beef steers commonly grazing an HE pasture. The third goal was to test the hypothesis that sodium selenite (ISe), SEL-PLEX (OSe), vs. a 1:1 blend (MIX) of ISe and OSe in a basal vitamin-mineral (VM) mix would differentially alter selenoprotein profiles in pituitaries and livers of growing beef steers commonly grazing an endophyte-infected tall fescue (HE) pasture (i.e., the same steers used in Goal 2). The effects of Se treatment on relative gene expression were subjected to one-way ANOVA. The mRNA content of 6 selenoproteins in the pituitary was affected by Se treatments, along with two selenoprotein P receptors, whereas the expression of two selenoproteins was altered in the liver. We conclude that the change in selenoprotein gene expression in pituitaries indicates that OSe steers have a greater potential capacity to manage against oxidative damage, maintain cellular redox balance, and have a better quality control of protein-folding in their pituitaries than ISe steers. The change in selenoprotein gene expression by the liver indicates that MIX steers have a greater redox signaling capacity and capacity to manage oxidative damage than ISe steers. KEYWORDS: Bovine pituitary, Ergot alkaloid, Fescue toxicosis, Prolactin, Selenium, Selenoprotein Qing Li March 22, 2019 RESPONSES OF BOVINE PITUITARY TRANSCRIPTOME PROFILES TO CONSUMPTION OF TOXIC TALL FESCUE AND FORMS OF SELENIUM IN VITAMIN-MINERAL MIXES By Qing Li Dr. James C. Matthews Director of Dissertation Dr. David L. Harmon Director of Graduate Studies March 22, 2019 ACKNOWLEDGEMENTS I would like to express my sincere gratitude to my mentor Dr. James Matthews for his extensive knowledge, patience, and continuous support of my Ph.D. study. Besides my mentor, I would like to thank the rest of my Ph.D. committee: Dr. Karen McDowell, Dr. Kuey Chen, Dr. Phillip Bridges, and Dr. Robert Harmon, for their encouragement, insightful comments, and valuable suggestions. In addition, I would like to thank Kwangwon Son, Yang Jia, and Charles Hamilton for their warm help and genuine concern. Last but not the least, I would like to thank my family, for their endless love and support, especially my wife Shuang Liu. I could not have done this without them. iii TABLE OF CONTENTS RESPONSES OF BOVINE PITUITARY TRANSCRIPTOME PROFILES TO CONSUMPTION OF TOXIC TALL FESCUE AND FORMS OF SELENIUM IN VITAMIN-MINERAL MIXES1 ACKNOWLEDGEMENTS ............................................................................................... iii TABLE OF CONTENTS ................................................................................................... iv LIST OF TABLES ............................................................................................................. ix LIST OF FIGURES .........................................................................................................