Seasonal and species variations in the nutritive value of eucaliptus foliage as a potential feed resource for ruminants in silvopastoral systems

10 páginas, 1 figura, 4 tablas.

The objective of the study was to evaluate the nutritional value of leaves from fve eucalyptus species (Eucalyptus astringens, E. leucoxylon, E. sideroxylon, E. lehmannii, E. camaldulensis), harvested in Tunisia (two locations) during the autumn, winter, and spring seasons. Chemical composition and digestibility (various in vitro procedures) and in vitro tannin biological activity were determined. The species E. lehmannii had the lowest neutral detergent fber (NDF) and lignin contents (252 and 92 g kg−1 dry matter (DM), respectively) and the highest nonfbrous carbohydrates content (553 g kg−1 DM), while the species E. leucoxylon and E. camaldulensis had the highest NDF concentrations (375 and 356 g kg−1 DM, respectively). Among the seasons, higher levels of NDF and lignin were observed in winter (349 and 129 g kg−1 DM, respectively). The species E. sideroxylon showed the highest gas production with polyethylene glycol addition and thus the highest biological tannin activity. The species E. lehmannii and E. camaldulensis had the highest metabolizable energy concentrations, with 6.20 and 6.07 MJ kg−1 DM, respectively. E. camaldulensis showed the highest (37.9%) and E. lehmannii the lowest (31.9%) organic matter digestibility. Foliage from eucalyptus trees are of limited energy and protein value as an alternative fodder for ruminants, with a substantial variability across species. No remarkable seasonal variations in chemical composition and digestibility of eucalyptus foliage were detected.

Peer reviewed