title: Transcriptomic markers meet the real world: finding diagnostic signatures of corticosteroid treatment in commercial beef samples.
abstract: BACKGROUND
  The use of growth-promoters in beef cattle, despite the EU ban, remains a frequent practice. The use of transcriptomic markers has already proposed to identify indirect evidence of anabolic hormone treatment. So far, such approach has been tested in experimentally treated animals. Here, for the first time commercial samples were analyzed.
  
  
  RESULTS
  Quantitative determination of Dexamethasone (DEX) residues in the urine collected at the slaughterhouse was performed by Liquid Chromatography-Mass Spectrometry (LC-MS). DNA-microarray technology was used to obtain transcriptomic profiles of skeletal muscle in commercial samples and negative controls. LC-MS confirmed the presence of low level of DEX residues in the urine of the commercial samples suspect for histological classification. Principal Component Analysis (PCA) on microarray data identified two clusters of samples. One cluster included negative controls and a subset of commercial samples, while a second cluster included part of the specimens collected at the slaughterhouse together with positives for corticosteroid treatment based on thymus histology and LC-MS. Functional analysis of the differentially expressed genes (3961) between the two groups provided further evidence that animals clustering with positive samples might have been treated with corticosteroids. These suspect samples could be reliably classified with a specific classification tool (Prediction Analysis of Microarray) using just two genes.
  
  
  CONCLUSIONS
  Despite broad variation observed in gene expression profiles, the present study showed that DNA-microarrays can be used to find transcriptomic signatures of putative anabolic treatments and that gene expression markers could represent a useful screening tool.
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padua, Viale dell'Università 16, 35020 Legnaro, Padova, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Pegolo
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Gallina
authors.forename: Clara
authors.initials: C
authors.lastname: Montesissa
authors.forename: Francesca
authors.initials: F
authors.lastname: Capolongo
authors.forename: Serena
authors.initials: S
authors.lastname: Ferraresso
authors.forename: Caterina
authors.initials: C
authors.lastname: Pellizzari
authors.forename: Lisa
authors.initials: L
authors.lastname: Poppi
authors.forename: Massimo
authors.initials: M
authors.lastname: Castagnaro
authors.forename: Luca
authors.initials: L
authors.lastname: Bargelloni
mesh_terms: D000305:Adrenal Cortex Hormones / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D005786:Gene Expression Regulation / Q000187:drug effects*; D005819:Genetic Markers; D006133:Growth Substances / Q000494:pharmacology; D008297:Male; D008460:Meat / Q000032:analysis* / Q000592:standards; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D025341:Principal Component Analysis; D040081:Protein Array Analysis; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D000305:Adrenal Cortex Hormones; D005819:Genetic Markers; D006133:Growth Substances; D009124:Muscle Proteins