Abstract

CLAVERO, Tyrone  and  RAZZ, Rosa. Dynamic of early fermentation on nitrogenous compounds in silages of Acacia mangium. Zootecnia Trop. [online]. 2008, vol.26, n.3, pp.253-255. ISSN 0798-7269.

The dynamics of fermentation were studied on silage of Acacia mangium in the northwest of Venezuela. Chopped fresh plant materials were ensiled in a laboratory silo, with a relationship of 1:2 (w.v) of legume:molasses, stored at 25ºC, and opened at 0.5, 3, 5, 7, 14, and 30 d of silage. The samples were taken from three silos at each sampling time and nitrogenous components were analyzed. A completely randomized design with three replications was used; significance among storage periods was determined by Tukey test. Measurements included total nitrogen (TN), protein nitrogen (PN), ammonia nitrogen (AN), soluble nitrogen (SN), PN/TN, N-NDF/TN, and N-ADF/TN. The fermentation dynamics showed a significant decrease (P<0.05) in the levels of TN, PN, PN/TN, N-NDF/TN, and N-ADF/TN which reached the lowest levels at 30 d (1.61%, 0,.81%, 50.39 g/kg, 32.70 g/kg, and 9.30 g/kg, respectively). TN and PN showed a decrease within the initial 7 d (P<0.05), with 8.6 and 17.8%, respectively, followed by an insignificant decrease. The reduction in PN was related to the formation of tannin-nitrogen complexes. SN increased gradually and reached the maximum value (0.68%) on day 30. However, SN levels were under 50% of TN. AN was detected in small amounts in silage, so SN was associated with the breakdown of nitrates and nitrites by the action of enzymes and enterobacteria. This study showed that mixture of Acacia mangium with molasses inhibited proteolysis during fermentation of the silage resulting in early stabilization of the medium.

Keywords : Silage; Acacia mangium; nitrogenous compounds.

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