Resumo

GAVIRIA, Xiomara; NARANJO, J. F  e  BARAHONA, R. In vitro fermentation kinetics of Leucaena leucocephala and Megathyrsus maximus and their mixtures, with or without energy supplementation. Pastos y Forrajes [online]. 2015, vol.38, n.1, pp. 55-63. ISSN 2078-8452.

In order to characterize the in vitro fermentation kinetics of Leucaena leucocephala and Megathyrsus maximus mixtures, an in vitro gas production trial was conducted in which five treatments were included: 100 % of L. leucocephala (L100), 100 % of M. maximus (G100), 100 % of supplement based on rice meal and molasses (S100), and two proportions: L23-G77 and L26-G70-S4. The forages were collected during eight months in an intensive silvopastoral system (SPSi), belonging to the Agricultural Center Cotové of the National University of Colombia. The maximum gas production varied in a range of 156 (L100) to 247 mL g^-1 substratum (L26-G70-S4). The lowest gas volume at the inflection point (57,5 mL) was observed in L100, which was different from the mixtures and the supplement (p < 0,05). The disappearance of the DM at 96 h varied between 53,8 % and 66,9 %, and it was higher in L100 than in the other treatments (p < 0,05). The lowest gas production value (1,31 mL) for each gram of DM, fermented at 96 h, was observed in L100 (p < 0,05). The results suggest that the inclusion of leucaena increased the concentration of protein in the diet and reduced the NDF content, which is positive from the point of view of animal productivity. It is concluded that the utilization of higher nutritional quality forages, such as that of leucaena, modifies the fermentation profile of the diet; for which the response of the forage-grass mixtures is different from the expected one, because it depends on the individual response of each forage

Palavras-chave : Gases; animal productivity; silvopastoral systems.

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