Resumo

BALDIZAN, Alfredo et al. Secondary metabolites in a tropical deciduous forest vegetation of the Venezuelan central plains. Zootecnia Trop. [online]. 2006, vol.24, n.3, pp.213-232. ISSN 0798-7269.

The presence of some groups of secondary metabolites (phenols, condensed tannins, saponins, cyanogens and alkaloids) in the edible biomass of 41 species in the tropical deciduous forest vegetation of the Central Plains, Venezuela were investigated. Forty four per cent of the species corresponded to leguminous plants. The Mimosoide subfamily contained 50% of the cases; while Faboide and Caesalpinoide were present in 28 and 22%, respectively. Phenols (83%) and alkaloids (61%) showed a greater general distribution. The quadruple combinations of secondary groups were the most abundant in leguminous (33%) and the double in non leguminous species (61%). In some representative species, a marked effect of the season, the forest type, and the geographical location were observed. However, it depended of the phytochemical particularities. By microhistological tests a wide range of acceptability were observed. In general, cattle consumed eagerly species with few metabolites combinations; while goats showed non specific preferences. The edible biomass of analyzed species contains some secondary metabolites groups whose presence, in some cases, varies with season, the forest type and location. Phenols and alkaloids are the groups that require bigger attention for their possible antinutricional repercussion.

Palavras-chave : phytochemical composition; metabolites; tropical deciduous forest; toxics; fodder species.