Fermentation characteristics and nutritional value of elephant grass ensiled with old man saltbush

摘要

The effects of the addition of saltbush on the fermentation characteristics and nutritional value of silages of elephant grass (Pennistum purpureum Schum.) were studied through a completely randomized design with six old man saltbush (Atriplex nummularia Lind) levels (0, 20, 40, 60, 80 and 100 %) in substitution of the grass natural matter, with six replicates. Elephant grass presented 18.9% dry matter (DM) and silages were produced in experimental PVC silos, which were open at 70 days after ensilage. The increasing old man saltbush levels had increasing linear effect on the DM content of silages. There was quadratic effect for the contents of lactic and acetic acids and in vitro DM digestibility. Contents of butyric acid were negligible. Values pH of and N-NH3 contents had increasing linear effect. Linear effect of the increasing levels of old man saltbush was verified on the CP contents. Neutral detergent fiber, total carbohydrates and ether extract were not affected, whilst acid detergent fiber content showed decreasing linear effect. The addition of old man saltbush in the ensilage of elephant grass favored the fermentation process, promoting good lactic acid contents and reducing acetic acid, pH, dry matter loss and ammoniacal nitrogen, in addition to improving the nutritional quality of the elephant grass silages.