Abstract
The effects of applying a commercial lactic acid bacteria (LAB) inoculant and two commercial cellulases on the fermentation quality and chemical composition of naked barley straw silages were investigated in two laboratory-scale experiments. In experiment 1, naked barley straw was untreated (Control) and treated with LAB at 1.0×10^5 cfu (colony forming unit)・g^<-1>, cellulases (Acremonium cellulase, Meicelase and their mixture at a 1:1 ratio) at the rate of 0.02% fresh matter and combinations of LAB and above cellulases. In experiment 2, naked barley straw was treated with control and Acremonium cellulase or Meicelase at the rates of 0.005, 0.01, 0.02, 0.04 and 0.08% fresh matter and LAB inoculant was added to all treatments at the same rate as in experiment 1. All the laboratory silos in both experiments were stored at room temperature. Experiment 1, the addition of LAB alone had a relatively small effect on the silage fermentation quality, whereas the addition of cellulases markedly improved the silage fermentation quality as indicated by a greater decrease in pH and butyric acid content and a larger build-up of lactic acid. When cellulases were added with LAB inoculant, the fermentation quality was further improved as compared with either cellulase or LAB alone. Experiment 2, as the applying rate of cellulases increased, pH value, butyric acid content, the VBN content, the concentrations of neutral detergent fiber, acid detergent fiber, crude fiber and cellulose of the silages decreased, whereas the contents of lactic acid, total acid, water-soluble carbohydrates and in vitro dry matter digestibility increased. Based on the results of both experiments, naked barley straw could be well preserved using cellulases added with LAB. Regarding cellulase as an additive of silage, Acremonium cellulase was more efficient than Meicelase and their mixture was intermediate.
