Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands
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Date
2012
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Spanish Journal of Agricultural Research
Abstract
Many wild browse and bush species are undervalued mainly because of insufficient knowledge about their potential
feeding value. The objective was to evaluate some nutritional attributes of various Algerian browse and shub species
(Atriplex halimus, Artemisia campestris, Artemisia herba-alba, Astragalus gombiformis, Calobota saharae, Retama raetam,
Stipagrostis pungens, Lygeum spartum and Stipa tenacissima). Chemical composition, phenols and tannins concentration,
in vitro digestibility, in vitro gas production kinetics and in vitro bio-assay for assessment of tannins using buffered
rumen fluid, and in situ disappearence of the edible parts of the plants (leaves, thin twigs and flowers) were determined. In
general, protein content in dicotyledon species was always greater than in monocotyledon grasses, these showing higher
neutral and acid detergent fibre and lower lignin contents than dicots. The tannin concentrations varied considerably between
species, but in general the plants investigated in this study had low tannin contents (except for Artemisia spp. and S. tenacissima).
Monocots showed lower in vitro and in situ digestibilities, fermentation rate, cumulative gas production and
extent of degradation than dicot species. The plants were clustered by principal components analysis in two groups:
poor-quality grasses and the most digestible dicot species. Chemical composition (neutral detergent fibre and protein) and
digestibility were the main influential variables determining the ranking. In conclusion, A. halimus, A. campestris,
A. herba-alba and A. gombiformis can be considered of greater nutritional value than the highly fibrous and low digestible
grasses (S. pungens, L. spartum and S. tenacissima) that should be considered emergency roughages