Global Mycotoxin Occurrence in Feed: A Ten-Year Survey

Abstract

Mycotoxins contaminating animal feed can exert toxic effects in animals and be transferred into animal products. Therefore, mycotoxin occurrence in feed should be monitored. To this end, we performed a large-scale global survey of mycotoxin contamination in feed and assessed regional differences and year-to-year variation of mycotoxin occurrence. Concentrations of aflatoxin B₁, zearalenone, fumonisins, ochratoxin A, deoxynivalenol, and T-2 toxin were analyzed in 74,821 samples of feed and feed raw materials (e.g., maize, wheat, soybean) collected from 100 countries from 2008 to 2017. In total, 88% of the samples were contaminated with at least one mycotoxin. Mycotoxin occurrence showed distinct regional trends and climate was a key determinant governing these trends. In most regions, the majority of samples complied with maximum levels and guidance values for mycotoxins in animal feed that are in effect in the European Union. However, 41.1%, 38.5%, and 20.9% of samples from South Asia, Sub-Saharan Africa, and Southeast Asia, respectively, exceeded the maximum level for aflatoxin B₁ (20 µg/kg). In several regions, mycotoxin concentrations in maize showed a pronounced year-to-year variation that could be explained by rainfall or temperature during sensitive periods of grain development. A large fraction of samples (64%) was co-contaminated with ≥ 2 mycotoxins. Most frequently observed mycotoxin mixtures were combinations of deoxynivalenol, zearalenone, and fumonisins, as well as fumonisins and aflatoxin B₁. Deoxynivalenol and zearalenone concentrations were correlated in maize and wheat. In conclusion, according to an extensive global survey, mycotoxin (co-)contamination of animal feed is common, shows regional trends, and is governed in part by climate and weather.

Keywords: Africa; America; Asia; Europe; animal; climate; feed; maize; mycotoxin; weather.

Figure 1

Occurrence of mycotoxins in 15 geographic regions. For each region, countries of sample origin are labeled in the map using a distinct color. The legend indicates percentage of positive samples and median of positive samples for each mycotoxin in each region. Each row represents one region and is labeled using the distinct color corresponding to the respective region in the map. n–sample number; AFB₁–aflatoxin B₁; DON–deoxynivalenol; ZEN–zearalenone; FUM–fumonisins (sum of fumonisins B₁, B₂,and B₃); OTA–ochratoxin A; T-2–T-2 toxin.

Figure 2

Year-to-year variation of mycotoxin concentrations in North America, South America, Northern Europe, Central Europe, Southern Europe, and Eastern Europe. The vertical axis shows mean concentrations of mycotoxins (Bayesian mean with error bars for 95% confidence level; see the Materials and Methods section for details on statistical analysis). The horizontal axis shows harvest years 2008–2017. Taking into account approximate seasons of crop growth and harvest, a year was defined to start in April and end in March of the subsequent calendar year for South America or to start in October and end in September of the subsequent calendar year for all other regions. Yellow circles and lines indicate maize samples. Blue circles and lines indicate finished feed samples. Data points are shown if ≥ 20 samples per year were available.

Figure 3

Year-to-year variation of mycotoxin concentrations in Middle East/North Africa, South Africa, South Asia, Southeast Asia, and East Asia. The vertical axis shows mean concentrations of mycotoxins (Bayesian mean with error bars for 95% confidence level; see Materials and Methods section for details on statistical analysis). The horizontal axis shows harvest years 2008–2017. Taking into account approximate seasons of crop growth and harvest, a year was defined to start in April and end in March of the subsequent calendar year for South Africa or to start in October and end in September of the subsequent calendar year for all other regions. Yellow circles and lines indicate maize samples. Blue circles and lines indicate finished feed samples. Data points are shown if ≥ 20 samples per year were available.

Figure 4

Correlation of zearalenone and deoxynivalenol concentrations in samples of maize (red circles) and wheat (turquoise circles). Both axes are in logarithmic scale.

Figure 5

Rainfall and temperature in maize-growing areas of Central Europe, Southern Europe, Southeast Asia, and China in 2013–2017. Bars indicate weekly total rainfall. Green, black, and light blue bars correspond to the approximate maize growing season, silking period, and off-season, respectively (these timings can differ between regions and management practice, and are affected by weather). Orange dots indicate weekly mean temperature. The vertical axis shows rainfall (in mm) and temperature in (°C). The horizontal axis indicates the months (J–January, F–February, M–March, A–April, M–May, J–June, J–July, A–August, S–September, O–October, N–November, D–December).