Pesquisa de lactonas do ácido resorcílico em urina bovina: detecção, quantificação e discriminação entre o uso de implantes ilegais de zeranol e ingestão de milho contaminado com Fusarium spp. toxinas

Abstract

Resorcylic acid lactones (RALs) include zearalenone (ZEA), α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), zeranol (α-zearalanol, α-ZAL), and taleranol (β-zearalanol, β-ZAL), among others. They are secondary metabolites of fungi that may exhibit various biological activities. Zeranol, when produced synthetically, has been used in cattle as an estrogenic growth promoter to improve meat production, although it is considered illegal in some countries, including Brazil. ZEA, produced by fungi of the genus Fusarium, may be present in grains used in animal feed and its consumption causes RALs, including zeranol, to be excreted in the urine. To distinguish between natural contamination of grains and illegal use of estrogen promoters, a mathematical equation based on linear regression with a 99% prediction interval was developed in the European Union. Based on these aspects, the objectives of this study were to evaluate the behavior, over time, of RALs in the urine of cattle that received feed contaminated with ZEA, zeranol implant, and the combination of contaminated feed and implant. To investigate the presence and levels of residues in the urine of the animals, a high-performance liquid chromatography system coupled to sequential mass spectrometry (LC-MS/MS) was used. The results demonstrated the presence of all RALs in the urine of animals that received contaminated feed and that received the combination of contamination and implant, with ZEA, α-ZEL, and β-ZEL only being detected and quantified while the contaminated feed was offered. For animals that received the implant, only zeranol and taleranol were found in the urine. It was concluded that the equation recommended by the EU allowed differentiating the ingestion of naturally contaminated foods from the abuse of zeranol, and this is an important tool to assist in the decision of a non-compliant result of the presence of RALs in cattle urine.