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.

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The chemical composition and digestibility of foliage from nine browse plant species (Artemisia herba-alba, Atriplex halimus, Acacia nilotica, Acacia horrida, Acacia saligna, Faidherbia albida, Albizia julibrissin, Vicia faba and Punica granatum) grown in arid and semi-arid areas of Algeria were evaluated. Feed components were determined by proximate analysis, whereas phenolic and tannin compounds were analysed by colorimetric procedures and their activity tested using a biological assay. Digestibility was assessed by conventional gravimetric in vitro and in situ methods, and rumen fermentation kinetics were estimated from the in vitro gas production technique. The foliage from Acacia species was found to be a protein-rich fodder for ruminants, although the high lignin and tannin content of some species is an important constraint limiting its digestive utilization in the gastrointestinal tract. The leguminous fodder tree, A. julibrissin, has a high protein content and its foliage is highly digestible owing to its low tannin content. Foliage from P. granatum is a highly digestible browse for ruminants.

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