Comparative analysis of the mycobiota and mycotoxins contaminating corn trench silos and silo bags.

Background: Silage is one of the most important feed sources for bovines. Mycotoxin contamination of feedstuffs is a worldwide concern. The aim of this study was to compare mycobiota and levels of aflatoxin B₁ (AFB₁), fumonisin B₁ (FB₁), deoxynivalenol (DON), zearalenone (ZEA) and patulin (PAT) in corn trench silos and silo bags.

Results: Dry matter was higher in trench silos. Counts varied from not detected to 10⁸ CFU g⁻¹ in both trench silos and silo bags. Isolation frequencies of Aspergillus spp. and Fusarium spp. were higher in trench silos, whereas Penicillium spp. was higher in silo bags. Silo bags showed less diversity than trench silos. Strains isolated produced AFB₁, FB₁ and PAT. In trench silos, AFB₁ was the only mycotoxin detected (1-160 µg kg⁻¹). In silo bags AFB₁ levels varied from 5.8 to 47.4 µg kg⁻¹. DON was detected in two silo bag samples.

Conclusion: When handling is adequate the reduction of mould and mycotoxin contamination in silo bags is considerable. This study will enable estimation of the mycotoxicological risk of different ensiling practices and determination of the most adequate method to minimize economic losses and reduce hazard to animal and human health.