Pojavnost tiouracila u svinjećim i goveđim urinima prikupljenih na hrvatskim farmama

Abstract

Thyrostats are a group of forbidden substances in food producing animals that increase water absorption in muscle tissue and the gastrointestinal tract of animals. These substances can be abused as illegal growth promoters as oral drugs on farms before slaughtering. The consequences of their illegal use on farm animals include higher yield though inferior meat quality, while these substances also pose a potential risk to human health, and so their application is banned in European Union Member States. Thiouracil (2-thiouracil) (TU) is the representative, and belongs to the group of thyrostats but also can be naturally present in the urine of farm animals fed with feed containing Brassicaceae species. The aim of this study was to monitor TU concentrations in pig and bovine urine in the period from 2015 to 2023. For this purpose, 391 urine samples were collected as a part of the National Residue Control Plan (NRCP) and TU concentrations were determined by liquid chromatography tandem mass spectrometry. TU was detected in 89 of 391 samples, or 22.76%. TU concentration ranged from 1.66 to 28.30 μg/L, and a statistically significant difference (P < 0.05) was determined in urine TU concentrations between pigs and bovines. Mean concentrations of TU varied by year, and ranged from 1.66 to 8.06 μg/L in pig urine and from 5.92 to 13.68 μg/L in bovine urine. None of the analysed urine samples contained TU concentration in excess of 30 μg/L, which is the cut-off value to distinguish potentially natural origin resulting from a cruciferous diet (Brassicaceae species). The results exclude the possibility of abuse of this substances in the livestock industry in the Republic of Croatia.