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Title: Proteomic and metabolomic blood profiling to detect illegal drug use in food producing animals
Author: Kinkead, Ruth Ann
ISNI:       0000 0004 6060 122X
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2016
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Despite the EU prohibition of anabolic substances administered to food producing animals, reports suggest that the use of growth promoting agents continues, pursued by improved animal health and subsequent financial gains. Current screening methods targeting known compounds are insufficient in discriminating endogenous levels from exogenous applications such as oestradiol. Problems also exist in the detection of corticosteroid misuse through long term, low dose dexamethasone and prednisolone administrations. Efforts have moved towards assessment of the biological response of animals to detect growth promoter exposure and methods employing proteomic'and metabolomic markers are needed. An in vivo animal study consisting of twenty-four male beef cattle randomly assigned to four groups (n=6) for experimental treatment over 40 days was conducted; a control group of untreated bovines, and three groups administered oestradiol, dexamethasone or prednisolone at levels known to reflect growth promoting practice. Plasma was collected from each animal throughout the treatment period and assessed for effect-based monitoring. An untargeted assessment of the plasma proteome utilising two-dimensional gel electrophoresis highlighted 22 proteins showing differential expression in treated cattle. Identification of protein markers via LC-MS/MS elucidated contributions to lipid and vitamin metabolism as well as the immune response. Similarly, untargeted metabolomic analysis was conducted via UHPLC-QTof-MS based on reverse phased separation of plasma under positive electrospray ionisation. Results demonstrated metabolite modifications relative to each treatment group and an OPLS-DA model was generated to predict treated from untreated cohorts based on 99 ions of interest. Further statistical analysis found 24 metabolites significantly altered within treated bovines which were putatively identified as mainly lipid components. Further verification of the biomarkers identified was conducted through targeted assessment of the relative levels in additional sample cohorts. A UHPLC-SRM-MS method was developed to detect eight plasma proteins of interest by quantification of tryptic peptides highlighting the use of vitamin-D binding protein, leucine-rich alpha-2-glycoprotein, retinol-binding protein 4 as novel markers responsive to growth promoter treatment. Additionally blood collected at the slaughterhouse was assessed for protein and metabolite perturbations to reflect authentic screening practice.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available