Quality and fermentation profile of sugar cane silage treated with chemical and microbial additives

Abstract Text: The objective of this study was to evaluate the composition and fermentation profile in sugar cane silage treated with chemical and microbial additives. The treatments consisted of sugar cane silage (SCS); Sugar cane silage with Lactobacillus buchneri (SCSLB); Sugar cane silage with Lactobacillus plantarum and Pediococcus pentosaceus (SCSLPPP); Sugar cane silage with Lactobacillus plantarum and Propionibacterium acidipropionici (SCSLPPA); Sugar cane silage with 0.5% lime (SCSCaO0.5); sugar cane silage with 1.0% lime (SCSCaO1.0); Sugar cane silage with 0.5% urea (SCSU0.5); sugar cane silage with 1.0% urea (SCSU1.0). Additives commonly used by Brazilian producers were studied. A completely randomized design was used, with eight treatments and four replicates, with inoculants before ensiling. The sugar cane was chopped and ensiled in 20 kg buckets containing Bunsen valves, and opened 180 days after ensiling. It was observed that the sugar cane silage treated with urea markedly increased protein levels and reduced levels of insoluble nitrogen in acid detergent in the silage. However, the concentration of ammonia nitrogen was also increased (P < 0.05). Lime 0.5% and urea 0.5% (5.8 and 5.6, respectively) promoted minor gas losses (P < 0.05) in relation to the addition of Lactobacillus plantarum and Pediococcus pentosaceus in the sugar cane silage (9.8% DM). Effluent average production was not affected by treatments (P > 0.05), but it can be considered high in comparison to other works using sugar cane silage. Increased dry matter recovery (P < 0.05) was observed in the control silage (87.2%) and SCSCaO0.5 (87.2%) compared to SCSLPPP (81.9%), possibly due to increased gas production seen in this treatment. SCSCaO0.5 (9.21% DM) also promoted the highest yield of lactic acid  (P < 0.05). The addition of 1% lime increased production of propionic and butyric acids (P < 0.05). It was found that the inoculation with Lactobacillus plantarum and Propionibacterium acidipropionici increased ethanol (P < 0.05) content (3.55% DM), and the lowest ethanol concentration was observed in SCSCaO0.5 (0.69% DM). Yeast population (P < 0.05) was lower in SCSU1.0 (1.4 log cfu/g) compared to SCSLPPP (4.6 log cfu/g), but both did not differ from control (3.9 cfu/g). Therefore, none of the treatments was effective in controlling yeast. It is concluded that the silages studied presented appropriate profile for fermentation, low yeast population concentration, low ethanol concentration and high recovery of dry matter.

Keywords: effluent, ethanol, yeast