Occurrence of moulds and mycotoxins in grass-legume silages influenced by nitrogen fertilization and phenological phase at harvest

摘要

The aim of this study was to determine the presence of fungi and concentrations of mycotoxins,zearalenone, fumonisin and deoxynivalenol, in lucerne and grass-legume silages, under the influence ofdifferent doses of N fertilization and harvesting at different stages of phenological development of theplants. Studies included pure lucerne crop and mixtures of lucerne with cocksfoot, tall fescue andsainfoin, sown in different ratios, fertilized with 0, 70, 140 or 210 kgN ha-1 and harvested in thebutonization phase or at 50% flowering of lucerne plants. Results showed that the total fungi count inthe silage depended on the three investigated factors. The highest total fungi count was determined inthe mixture silages of lucerne, cocksfoot and tall fescue, which was well treated with different nitrogenquantities, harvested and prepared in later stages of plant development. The most commonly-occurringfungi were Fusarium species (85.5% of fungi were this genus). Of the studied mycotoxins, only DONdepended on fertilization, as it reduced the concentration of DON from 0.15 to 0.07 mg kg-1.Preventing appearance of fungi and their mycotoxins in forage and silage should begin in thefield as well as during the process of preparation of silage.