Influence of species and preservations on the quality and safety of grass silages

Abstract

The paper evaluates the quality of model silages made of wilted grass biomass and treated with silage additives. Grass species used for the production of silages were Lolium perenne, Festulolium pabulare and Festulolium braunii harvested in the first cut at the stage of earing. The assessed grass species were wilted after the cut for an identical time 36 hours (2008), resp. 24 hours (2009). The treatment was made either with a chemical preparation (formic acid, propionic acid, ammonium formate) and/or with a bio­lo­gi­cal inoculant (Enterococcus faecium, Lactobacillus plantarum, Pediococcus acidilactici, Lactobacillus salivarius, cellulase, hemicellulase and amylase). The amount of the chemical ingredient was 4 l . t−1 and the amount of the biological additive was 10 g . t−1.The biomass was after wilting ensilaged in con­tai­ners whose diameter and height were 0.15 m and 0.64 m, respectively. After 60 days of ensilaging, the silages were assessed for pH, organic acids content, ethanol content and acidity of water extract (AWE); organic nutrients assessed in the silages were crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF), crude protein (CP) and digestibility of organic matter (DOM). Hygienic safety was assessed from the contents of zearalenon, fumonisin and aflatoxin mycotoxins. The high (P < 0.05) dry matter (DM) content in Festulolium pabulare silages indicates that the species tends to rapid wilting. The higher DM content reflected in lower biomass losses (P < 0.05). The lowest pH values (P < 0.05) were detected in silages made of Festulolium braunii. The fact relates to the higher content of lactic acid in the prepared microsilages. The use of ensiling additives affected the quality of extracts. Namely the application of the biological additive led to the increased content (P < 0.05) of not only lactic acid but acetic acid too. Titrable acidity was not affected by the ensiling additives. As to the emanation of ethanol, heterofermentative bacteria of lactic fermentation apparently took part in the fermentation process of the silages as well. While the evaluated forage species showed differences in the di­ges­ti­bi­li­ty of organic matter (P < 0.05), the application of preservatives did not influence the content of organic nutrients. Fumonisin was not detected at all and aflatoxins were below the level of detection. None of the assessed factors had an effect on the content of zearalenon; in spite of the fact, an apparent tendency towards a higher content of zearalenon was recorded in Lolium perenne.

Keywords

• <i>Lolium perenne</i>
• <i>Festulolium</i>
• silage fermentation
• organic nutrient
• mycotoxins