PF 27. Fermentation characteristics of forage sorghum ensiled with commercial enzyme preparations

Abstract

The objective of this experiment was to evaluate the effect of three commercial enzyme preparations on the fermentation characteristics and carbohydrate content of forage sorghum. Forage sorghum was harvested at 90 days of growth (20.04 % DM) at Michigan State University, East Lansing and chopped mechanically into 2.5 cm pieces. Chopped forage, prior to ensiling, was treated with three commercial enzyme preparations assigned to one of six treatments; no additive (control, T1), Viscozyme, 0.1% of fresh material, T2), Ecogram (0.08 mL\kg of fresh material, T3; and 0.16 mL\kg of fresh material, T4), and Cellulase G (0.25 mL\kg of fresh material, T5; and 0.50 mL\kg of fresh material, T6). Treatments were applied to weighed portions (1.6 kg) of forage, manually mixed, and packed into PVC laboratory silos fitted with release valves to provide gas escape. Laboratory silos were maintained at room temperature (27-30 °C) until opened. Triplicate samples from each treatment at each ensiling period were analyzed for pH, fermentation end-products (acetic and lactic acids, and ethanol), and water soluble (glucose, fructose, galactose, xylose and arabinose) and structural (NDF, ADF, cellulose, and hemicellulose) carbohydrate content. Data was analyzed as a completely randomized design with a 6 (enzyme preparations) by 3 (ensiling periods) factorial arrangement of treatments. Bonferroni t- test was used for mean separation. Results indicate that forage sorghum treated with Ecogram or Cellulase G increased the residual glucose content after 100 days of fermentation. However, neither enzyme preparation increased the acidity or lactic acid content of the resulting silage, and a decrease in xylose content was observed. Application of the enzyme mixture did not significantly decrease cell-wall components of forage sorghum silage. Therefore more research is needed to evaluate the effects of different enzyme preparations on the fermentation characteristics of silages.