Pyrosequencing investigation into the influence of Cu2+ Zn2+ Fe2+ and I− mixtures on fungal diversity and toxigenic fungal growth in a fermented liquid feed

摘要

A L9(3⁴) orthogonal experiment was conducted to evaluate the influence of 9 mixtures which consisted of Cu²⁺, Zn²⁺, Fe²⁺ and I⁻ ions at different ion concentrations on fungal diversity and toxigenic fungal growth in a Bacillus subtilis-fermented liquid feed (FLF) using pyrosequencing. The maximal Chao estimator and Shannon index were achieved in the FLF with a mixture of Cu²⁺ (200 mg/kg), Zn²⁺ (160 mg/kg), Fe²⁺ (150 mg/kg) and I⁻ (2.4 mg/kg). The minimal relative abundance of Aspergillus was achieved when a mixture of Cu²⁺ (200 mg/kg), Zn²⁺, Fe²⁺ and I⁻ was added to the FLF. Compared with Zn²⁺, Fe²⁺ and I⁻, Cu²⁺ was the most important ion in inhibiting Aspergillus growth. Adding Zn²⁺ (160 mg/kg), Cu²⁺, Fe²⁺ and I⁻ to the FLF minimized the relative abundance of Fusarium. It was Zn²⁺ instead of Cu²⁺ played a critical role in suppressing the growth of Fusarium. The proper use of the mixture of Cu²⁺, Zn²⁺, Fe²⁺ and I⁻ in FLF contributes to inhibit the growth of mycotoxin-producing fungi during storage. The new findings of this study help farmers properly use the mixture of Cu²⁺, Zn²⁺, Fe²⁺ and I⁻ to inhibit the growth of mycotoxin-producing fungi in the production of high quality FLF and alleviate mycotoxins damages to animals and humans.