The effect of lactic acid bacteria addition on microbiota and occurrence of mycotoxins in rye silages

Abstract

In the rye silages (control and with additive) microbiota isolation and identification (total count of bacteria, coliform bacteria, enterococci, lactic acid bacteria and microscopic filamentous fungi) and occurrence of mycotoxins were evaluated. Total count of bacteria on Plate count agar at 30 °C for 48-72 hours, coliform bacteria on McConkey agar at 37 °C for 24-48 hours, enterococci on Enterococcus selective agar at 37 °C for 48-72 hours, lactic acid bacteria on De Man, Rogosa and Sharpe agar, Mayeux, Sandine and Elliker and All Purpose TWEEN® agar 37 °C for 48-72 hours in microaerophilic condition and microscopic filamentous fungi on Malt extract agar at 25 °C for 7 days were evaluated and identified with mass spectrometry. The most isolated family from both types of silage was Lactobacillaceae. The most isolated species from the control group was Lentilactobacillus buchneri (22%) and lowest number of isolated species was Mucor spp. The most isolated species from silage with additive was Lactobacillus gasseri (16%). The ELISA method (enzyme-linked immunosorbent assay) with using reader at wavelength 650 nm for detection and quantification of mycotoxins (total aflatoxins, total ochratoxins, total fumonisins, deoxynivalenol, zearalenone and T-2/HT-2 toxin) was used. The rye silages of control and with additive were characterized by occurrence of all analyzed mycotoxins, whereas deoxynivalenol was mycotoxin with the highest concentration. The rye silages with additive had significantly lower content of total aflatoxins compared to the control, while significantly higher concentration of total ochratoxins, deoxynivalenol, zearalenone and T-2/HT-2 toxin was determined.

Keywords

• biological additive
• silage
• mycotoxin contamination
• bacteria
• microscopic filamentous fungi
• mass spectrometry