Applied Research Note: Biomonitoring of mycotoxins in blood serum and feed to assess exposure of broiler chickens

Summary: Because European maximum guidance values of mycotoxins are only available for feed, mycotoxin exposure in animals is mainly monitored by feed analysis. However, proper sample collection is needed to ensure reliable results because of uneven distributions and disproportional spread of mycotoxins in feed which can hamper the evaluation of mycotoxin exposure in animals. A cross-sectional study was performed on 40 randomly selected broiler farms in Belgium. During a farm visit at the animal's age of 28 d, a pooled feed sample at the beginning and the end of the feed line was collected. Feed samples were analyzed by a validated multimycotoxin LC-MS/MS method. Moreover, serum samples were collected from 10 randomly selected chickens per farm. Serum concentrations of mycotoxins and major in vivo phase I metabolites were analyzed quantitatively, whereas the presence of phase II metabolites was determined in a qualitative approach by an UPLC-HRMS method. Deoxynivalenol (DON) was the most frequently occurring mycotoxin, being present in 74% of the feed samples, with an average concentration of 270 ± 171 μg/kg and a maximum concentration of 751 μg/kg in positive samples. Also the acetylated forms 3- and 15-acetyldeoxynivalenol (3 and 15ADON) were present in half of the samples, however, at lower concentrations (8 ± 3 μg 3ADON and 10 ± 7 μg 15ADON/kg). Only in 17.5% of the farms, DON was detected in serum samples at a mean serum concentration and standard deviation (SD) of 11 ± 19 ng/mL. The maximum serum concentration of 49 ng DON/mL was detected in broilers which were fed a diet that was contaminated with 191 μg DON/kg, whereas the maximum concentration of DON in feed was 751 μg/kg. Besides, 3 and 15ADON were only detected in 10% of the serum samples (max. 1.3 ng/mL). Sulfate conjugates of DON were only detected in a few serum samples. Qualitative screening for phase II metabolites of other mycotoxins showed similar results. Overall, correlations between feed and serum concentrations of all mycotoxins were lacking (R2 = 0.18 for DON).