Estimation of multi-mycotoxin contamination in South African compound feeds

A total of 92 commercial compound feeds from South Africa were investigated for various mycotoxins. The data reveal the highest incidence of feed contamination for fumonisins (FB) (range: 104-2999 μg/kg) followed by deoxynivalenol (DON) (range: 124-2352 μg/kg) and zearalenone (ZEA) (range: 30-610 μg/kg). The incidence of ochratoxin A (OTA) and aflatoxins (AF)-contaminated samples were generally low, i.e., 4% and 30% of samples with levels ranging between 6.4 and 17.1 μg/kg (mean: 9.9 μg/kg) for OTA and 0.2 to 71.8 μg/kg (mean: 9.0 μg/kg) for AF. No samples contained T-2 toxin or HT-2 toxin. However, all samples analyzed were contaminated with at least one mycotoxin with a majority containing several mycotoxins. In particular, 3 of 4 positive samples mainly cattle feeds that had relatively high contents of OTA (ranging from 7 to 17.1 μg/kg) also contained high amounts of AF (>27.5 μg/kg) together with FB, DON and ZEA. Apart from a few samples, the levels of mycotoxins may be regarded as safe for livestock production in South Africa. However, the persistent co-occurrence of mycotoxins in samples, especially those at high concentrations, i.e., AF and OTA, together with other mycotoxins studied, may elicit synergistic or additive effects in animals. This should raise concern as multiple contaminations may pose a risk to livestock production and health.