PSIX-21 Assessment of multiple mycotoxins in total mixed rations for beef cattle feedlots in Brazil.

Abstract Mycotoxins are toxic substances produced by molds that can contaminate cattle feed and silage, which are consumed by the animals. The ingestion of these toxins can lead to a variety of health consequences, including decreased dry matter intake, reduced nutrient absorption, endocrine system changes, and immune system suppression. The present study aims to investigate the occurrence of multiple mycotoxins (aflatoxins, zearalenone, fumonisins, deoxynivalenol, T-2 and HT-2 toxin) present in the diet of beef cattle in Brazil throughout a one-year period (2023-2024). The samples analyzed were selected to be representative of the diet fed to 1,246,522 animals, with the locations distributed across 17 different cities in the seven largest states in Brazil. To this end, 152 total mixed ration (TMR) samples were meticulously prepared: ground, homogenized, and extracted for chromatographic analysis (LC-MS/MS). This analysis was conducted at the Mycotoxin Control and Decontamination Laboratory, University of São Paulo. For the statistical treatment of the results, α = 0.05 was adopted as the rejection level. The mass spectrometry analysis of the TMR samples detected the presence of fumonisins (FB; B1 and B2) in 100% of the samples, zearalenone (ZEN) in 79.6%, and aflatoxins in 62.5%. AF (B1 + B2 + G1 + G2), 35.5% were contaminated with deoxynivalenol (DON), and 8.6% had T-2, while HT-2 was not detected in any of the samples. The mean levels of the contaminated samples for AF, ZEN, FB, DON, and T-2 were, respectively: 5.7 + 7.7, 33.2 + 108.5, 2350.3 + 2737.4, 371.9 + 669.9, and 3.3 + 3.5 µg/kg/DM, respectively. The average probable daily intake (PDI) of mycotoxins was calculated to be 0.12, 0.67, 47.48, 7.51, and 0.07 µg/kg/bw, respectively, based on an average body weight (bw) of 550 kg. The findings of the present study indicate a high occurrence of mycotoxins, both from the Aspergillus and Fusarium genera, suggesting contamination problems both in the pre-harvest stage and during storage. Additional studies are necessary to establish risk levels and to further elucidate the effects of mycotoxins on beef production.