In Vivo Kinetics and Biotransformation of Aflatoxin B1 in Dairy Cows Based on the Establishment of a Reliable UHPLC-MS/MS Method

• Published in: Frontiers in chemistry 2021-12, Vol.9, p.809480-809480
• Main Authors: Guo, Wenbo, Fan, Zhichen, Fan, Kai, Meng, Jiajia, Nie, Dongxia, Tangni, Emmanuel K., Li, Zenghe, Zhao, Zhihui, Han, Zheng
• Format: Article
• Language: English
• Subjects: aflatoxins; biotransformation; Chemistry; dairy cow; in vivo kinetics; UHPLC-MS/MS
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2021.809480

The in vivo kinetics of aflatoxin B 1 (AFB 1 ) and its carry-over as aflatoxin M 1 (AFM 1 ) in milk as well as the toxin loads in the tissue of dairy cows were assessed through a repetitive feeding trial of an AFB 1 -contaminated diet of 4 μg kg −1 body weight (b.w.) for 13 days. This was followed by a clearance period that ended with a single dose trial of an AFB 1 -contaminated diet of 40 μg kg −1 b.w. An ultra-high performance liquid chromatography tandem mass spectrometry method was developed and successfully validated by the determination of linearity ( R 2 ≥ 0.990), sensitivity (lower limit of quantification, 0.1–0.2 ng ml −1 ), recovery (79.5–111.2%), and precision relative standard deviation (RSD) ≤14.7%) in plasma, milk, and various tissues. The repetitive ingestion of AFB 1 indicated that the biotransformation of AFB 1 to AFM 1 occurred within 48 h, and the clearance period of AFM 1 in milk was not more than 2 days. The carry-over rate of AFM 1 in milk during the continuous ingestion experiment was in the range of 1.15–2.30% at a steady state. The in vivo kinetic results indicated that AFB 1 reached a maximum concentration of 3.8 ± 0.9 ng ml −1 within 35.0 ± 10.2 min and was slowly eliminated from the plasma, with a half-life time (T 1/2 ) of 931.1 ± 30.8 min. Meanwhile, AFM 1 reached a plateau in plasma (0.5 ± 0.1 ng ml −1 ) at 4 h after the ingestion. AFB 1 was found in the heart, spleen, lungs, and kidneys at concentrations of 1.6 ± 0.3, 4.1 ± 1.2, 3.3 ± 0.9 and 5.6 ± 1.4 μg kg −1 , respectively. AFM 1 was observed in the spleen and kidneys at concentrations of only 0.7 ± 0.2 and 0.8 ± 0.1 μg kg −1 , respectively. In conclusion, the in vivo kinetics and biotransformation of AFB 1 in dairy cows were determined using the developed UHPLC-MS/MS method, and the present findings could be helpful in assessing the health risks to consumers.