CONICET | Buscador de Institutos y Recursos Humanos

The Argentinian silage inoculant market is highly dominated by foreign products. Moreover, most formulations are provided as freeze-dried cultures or as water-soluble concentrates, whereas spray-drying offers a rapid and cost-effective option with high production capacity of dried cells. Thus, the objective of this study was to compare the effects of adding a novel spray-dried inoculant and a commercial inoculant on the fermentation and aerobic stability of vetch-oat silages.A 3 × 4 factorial arrangement of treatments was used, with and without bacterial inoculants and four fermentation periods (0, 3, 30, 60 days), in a completely randomized design. Forage treatments were: no additive (Control); native inoculant containing Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and L. buchneri B463; and commercial inoculant SiloSolve MC (Chr. Hansen A/S, Hørsholm, Denmark). The plant material was ensiled in 36 polyethylene containers (10 L capacity), compacted, sealed and stored at room temperature during 60 days. Triplicate micro-silos were opened at each time point of anaerobic fermentation, and subsampled for analysis of fermentation parameters and microbiological counts. In addition, at the end of the ensiling period, the silages were subjected to an aerobic stability test.The decrease in pH was faster in the novel inoculant silage and in the silage with the commercial inoculant than in the control silage (p = 0.001). SiloSolve MC inoculated silage had the highest dry matter concentration, followed by the silage with the novel inoculant and the control (p = 0.001). The uninoculated silage had lower content of crude protein and higher concentration of neutral detergent fibre in comparison with the inoculated silages (p < 0.05). The highest concentration of ammonia nitrogen/total nitrogen was observed at day 60 for the control group (p = 0.001). Inoculation was not able to modify the variables acid detergent fibre, acid detergent lignin and ether extract of silages compared to control samples (p > 0.05). The number of lactic acid bacteria was significantly higher (p = 0.012) for inoculated samples than for uninoculated ones. There was a lower cell load of yeasts and moulds (p = 0.006) for native inoculated micro-silos compared to control and commercial inoculated samples. Higher concentrations of lactic, acetic and propionic acids were observed in the inoculated silages compared to the control (p > 0.05). An elevated content of ethanol was observed in the control silage at day 60 (p = 0.001). Regarding the aerobic stability test, the control silage was stable for 47 h, while the inoculated silages were stable at least for 96 h, when the experiment was stopped. The temperature in the uninoculated silage reached 10 °C above the ambient temperature during the assessment period. The results obtained in this study confirmed that the native strains display potential to be used as a bio‐inoculant in oat-vetch silages.