Simultaneous Detection of Androgen and Estrogen Abuse in Breeding Animals by Gas Chromatography–Mass Spectrometry/Combustion/Isotope Ratio Mass Spectrometry (GC-MS/C/IRMS) Evaluated against Alternative Methods

The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring ¹³C/¹²C isotopic ratios of their urinary metabolites. Gas chromatography–mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) was used in this study to appraise in a global approach isotopic deviations of two 17β-testosterone metabolites (17α-testosterone and etiocholanolone) and one 17β-estradiol metabolite (17α-estradiol) together with those of 5-androstene-3β,17α-diol as endogenous reference compound (ERC). Intermediate precisions of 0.35‰, 1.05‰, 0.35‰, and 0.21‰, respectively, were observed (<i>n</i> = 8). To assess the performance of the analytical method, a bull and a heifer were treated with 17β-testosterone propionate and 17β-estradiol-3-benzoate. The sensitivity of the method permitted the demonstration of 17β-estradiol treatment up to 24 days. For 17β-testosterone treatment, the detection windows were 3 days and 24 days for the bull and the heifer, respectively. The capability of GC-MS/C/IRMS to demonstrate natural steroid abuse for urinary steroids was eventually compared to those of mass spectrometry (LC-MS/MS) when measuring intact steroid esters in blood and hair

De Cuyper et al_RawDataPredatorPreyRatios

Data spreadsheet including all raw literature data used for the scaling relationships predator size vs prey size, pack size, real observed kill frequency and gut capacity (see corresponding tabs). Legends are included to explain column headings (see corresponding tabs). Additionally, prey weights obtained from internet sources are provided in the spreadsheet

Additional file 1: of Does canine inflammatory bowel disease influence gut microbial profile and host metabolism?

Canine chronic entreropathy clinical activity index in IBD dogs. Description of data: the total CCECAI score and the individual score of each criterion. (XLSX 9 kb