THE EFFECT OF APPLYING LACTIC-ACID BACTERIA AT ENSILING ON THE AEROBIC STABILITY OF SILAGES

The effect of applying commercial lactic acid bacteria inoculants at ensiling on the aerobic stability of silages was studied under laboratory conditions. The silages used were wheat, hedysarum, corn and various sorghum cultivars at various stages of maturity. Three inoculants were used, two containing Lactobacillus plantarum, Enterococcus faecium and Pediococcus acidilactici (H/M F, Medipharm, USA and Sil-All, Alltech, UK) and one containing Ent. faecium (Lacticil, M74, Medipharm, Sweden). The inoculants were applied at 0.5 x 10(6) cfu g(-1). Silages with no additives served as controls. After treatment, the chopped forages were ensiled in 1.51 anaerobic jars; there were six jars per treatment. After ensiling for 45 d, the silages were tested for aerobic stability in a test in which CO2 production was measured along with chemical and microbiological parameters. The inoculated silages that spoiled upon aerobic exposure faster than the controls were those of wheat and of the sorghum cultivar FS5 at the milk stage of maturity. This was evident from intensive CO2 production and development of yeasts and moulds. Regression analysis indicated that aerobic deterioration of inoculated silages was associated with high levels of residual water-soluble carbohydrates and lactic acid and lack of volatile fatty acids. Aerobic spoilage of inoculated silages was attributed mainly to yeast activity.