Effect of the storage time and several silage inoculants on the aerobic stability of sorghum silages

Aerobic stability of silages has great importance in practice. When the silo is opened, yeasts and moulds can grow due to exposure to the air. The process cause significant loss of nutrients and harmful silage will be produced. There are lot of published results on the fermentability, the nutritive value and digestibility of sorghum silages, but we have only limited knowledge about their aerobic stability. The aerobic stability is affected by several factors. As the sugar content is high one of the most important fact is the amount of easily fermented carbohydrate remaining after the fermentation – in case of sorghum silage. In this paper we report the aerobic stability of sorghum silages changing in the function of storage time, using inoculants Lactobacillus buchneri (NCIMB 40788), Propionibacterium acidipropionici (MA 26/4U) and the preservative product Lalsil Fresh. Four treatments were used (T1 untreated control, T2 treated with Lactobacillus buchneri 3x105 CFU/g FM, T3 treated with Propionibacterium propionici 3x105 CFU/g FM, T4 treated with 0.005 g/kg Lalsil Fresh). The Lallemand inoculant “Lalsil Fresh” contained selected strain of Lactobacillus buchneri (NCIMB 40788 6x1010 CFU/g). Sorghum (Róna 1) was ensiled immediately after harvest, chopped to about 1-1.5 cm size, mixed with additives and ensiled in 4.2 L jars. The jars were incubated at 20+/-2 °C. Five jars per treatment were sampled on day 14, 28, 42, 56 and after 140 of storage. The aerobic stability, chemical and microbiological parameters were analysed from the silages. Strong correlation was observed between the aerobic stability and the storage time of silages. At the beginning of fermentation the aerobic stability was still low but changed better with the progress of time. After complete fermentation, from the eight week of ensilaging stable silages could be observed. The aerobic stability of silages opened on the twentieth week was more than one week. Positive effect of the heterolactic bacteria was established. The aerobic stability was increased moderately by Propionibacterium propionici, and significantly Lactobacillus buchneri. Lalsil Fresh had the best effect on aerobic stability. All the treated silages opened on the twentieth week had better aerobic stability than the untreated