Comparative analysis of silage fermentation and in vitro digestibility of tropical grass prepared with Acremonium and Tricoderma species producing cellulases.

OBJECTIVE: To find out ways of improving fermentation quality of silage, the comparative analysis of fermentation characteristics and in vitro digestibility of tropical grasses silage applied with cellulases produced from Acremonium or Tricoderma species were studied in Thailand.

METHODS: Fresh and wilted Guinea grass and Napier grass silages were prepared with cellulases from Acremonium (AC) or Trichoderma (TC) at 0.0025%, 0.005%, and 0.01% on a fresh matter (FM), and their fermentation quality, chemical composition and in vitro digestibility were analyzed.

RESULTS: All silages of fresh Napier grass were good quality with lower pH, butyric acid, and ammonia nitrogen, but higher lactic acid content than wilted Napier grass and Guinea grass silage. Silages treated with AC 0.01% had the best result in terms of fermentation quality. They also had higher in vitro dry matter digestibility and in vitro organic matter digestibility at 6 and 48 h after incubation than other silages. Silages treated with lower levels at 0.005% or 0.0025% of AC and all levels of TC did not improve silage fermentation.

CONCLUSION: The AC could improve silage fermentation and in vitro degradation of Guinea grass and Napier grass silages, and the suitable addition ration is 0.01% (73.5 U) of FM for tropical silage preparation.