Nutritive evaluation of foliage from fodder trees and shrubs characteristic of Algerian arid and semi-arid areas

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.