Alternative Forages as Roughage for Ruminant: Nutritional Characteristics and Digestibility of Six Exotic Plants in Azores Archipelago

Abstract

This study aimed to evaluate the nutritional potential of unconventional plants: Pittosporum undulatum, Cryptomeria japonica, Acacia melanoxylon, Hedychium gardnerianum, Eucalyptus globulus, and Arundo donax, as an alternative roughage for ruminants. Chemical composition, gross energy, in vitro gas production, kinetics, and digestibility of dry matter and organic matter in vitro were determined for each species. The obtained results showed variations between the studied forages concerning crude protein, and the different fiber fractions: NDF, ADF, and ADL The P. undulatum with a relative food value of 92.12%, showed a significant difference compared to the other species under study. After 96 h of incubation, the plants that produced, on average, less in vitro gas were A. melanoxylon and E. globulus. Among the studied species, A. donax stands out as the species that presented the highest gas production, with 31.53 mL. 200 mg−1 DM, observing a significant difference compared to the other plants. This is a reflection of it having the highest DMD (60.44 ± 1.22%) as well. P. undulatum was the species with the longest colonization time (4.8 h). Among the plants studied, we highlight P. undulatum as presenting a good quality in the RFV index and A. donax as having good digestibility. Both can be used as roughage in periods of greater shortage of pastures.