Composición química y digestibilidad de varias especies arbustivas características de pastizales en zonas áridas de Argelia

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.El objetivo de este trabajo fue el de evaluar varias especies arbustivas de Argelia (Atriplex halimus, Artemisia campestris, Artemisia herba-alba, Astragalus gombiformis, Calobota saharae, Retama raetam, Stipagrostis pungens, Lygeum spartum y Stipa tenacissima). Se determinó la composición química, la concentración de fenoles y taninos, la producción de gas y digestibilidad in vitro y la degradabilidad in situ de la parte comestible del pasto arbustivo (hojas, tallos finos y flores). Los contenidos en proteína y lignina fueron superiores en las dicotiledóneas que en las monocotiledóneas, mientras que los contenidos en fibra fueron más elevados en las monocotiledóneas. La concentración en taninos fue variable entre especies y, excepto para Artemisia spp. y S. tenacissima, los contenidos de estos compuestos fueron exiguos en la mayoría de las especies. Las monocotiledóneas fueron menos digestibles, con menores valores de ritmo de fermentación, producción de gas y degradabilidad ruminal. A partir de un análisis de componentes principales se observaron dos agrupaciones de las plantas: en un grupo las monocotiledóneas de baja calidad nutritiva y en otro grupo las dicotiledóneas más digestibles. Este agrupamiento fue determinado fundamentalmente por la composición química (fibra y proteína) y la digestibilidad. En conclusión, A. halimus, A. campestris, A. herba-alba y A. gombiformis pueden ser consideradas de mejor calidad (considerando su composición y digestibilidad), mientras que S. pungens, L. spartum y S. tenacissima podrían considerarse como recursos de baja calidad que sólo serían utilizados cuando no hay disponibilidad de otros alimentos

Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands

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

Nutritive evaluation of foliage from some Acacia's characteristic of Algerian arid and semiarid areas

Trabajo presentado en el 14th International Seminar of the FAO-CIHEAM Sub-Network on Sheep and Goat Nutrition: Feeding and management strategies to improve livestock productivity, welfare and product quality under climate change, p. S2-O-01. 15-18 de mayo de 2012. Túnez (Túnez).Peer reviewe

The effect of polyethylene glycol addition on methane gas production parameters of some browse plant species collected from Algerian arid rangelands

Trabajo presentado en el 14th International Seminar of the FAO-CIHEAM Sub-Network on Sheep and Goat Nutrition: Feeding and management strategies to improve livestock productivity, welfare and product quality under climate change, p. S4-P-03. 15-18 de mayo de 2012. Túnez (Túnez).Peer reviewe

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

16 páginas,5 tablas.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.L. Bouazza and S. Boufennara gratefully acknowledge the receipt of a Study and Doctoral Research Abroad Fellowship funded by the Algerian Ministry of Higher Education and Scientific Research to conduct the experimental work of their PhD projects at the University of León (Spain).Peer reviewe

Effet de l'addition de polyéthylène glycol sur la production in vitro de gaz et de méthane pour des plantes d'Algérie

5 páginas, 2 tablas.-- Contributed to: 14th International Seminar of the Sub-Network on Nutrition of the FAO-CIHEAM Inter-Regional Cooperative Research and Development Network on Sheep and Goats, "Feeding and management strategies to improve livestock productivity, welfare and product quality under climate change", jointly organized by INRAT and IAMZ-CIHEAM in collaboration with FAO the OEP of Tunisia, IRESA, and the LowInputBreeds project. Hammamet (Tunisia), 15-17 June 2012.Peer reviewe

Valeur nutritive du feuillage de quelques Acacia prépondérants des régions arides et semi-arides d'Algérie

6 páginas, 3 tablas.--Contributed to: 14th International Seminar of the Sub-Network on Nutrition of the FAO-CIHEAM Inter-Regional Cooperative Research and Development Network on Sheep and Goats, "Feeding and management strategies to improve livestock productivity, welfare and product quality under climate change", jointly organized by INRAT and IAMZ-CIHEAM in collaboration with FAO the OEP of Tunisia, IRESA, and the LowInputBreeds project. Hammamet (Tunisia), 15-17 June 2012.Peer reviewe

Rumen degradability of some Algerian browse plant species from arid rangelands

4 páginas, 1 tabla.The study was conducted in Boussâda district, in the arid Saharan Atlas region with the objective of evaluating the chemical composition and in situ rumen degradation of Algerian browse plants collected from arid rangelands. Six browse plant species were used in this study: four dicotyledon plants namely Atri - plex halimus, Artemisia herba-alba, Astragalus gombiformis and Calobota saharae and two monocotyledon plants, namely Lygeum spartum and Stipa tenacissima. Nylon bags containing foliage samples of each spe - cies were incubated for 0, 24 and 96 h (as indicators of solubility, degradation rate and potential degradabili - ty of the forages) in the rumen of three Merino sheep fitted with rumen fistula. Forages showed different (P<0.001) DM and NDF dissapearance rates. After 96 hours of incubation time, the highest in sacco DM disappearance was observed for A. gombiformis (0.85 g/g DM incubated) and the lowest was obtained with S. tenacissima (0.31 g/g DM incubated). In summary, dicot plants with high protein, low fiber and high DM ruminal degradability could be regarded as interesting roughages for use as ruminant feedstuffs.Peer Reviewe

Methane production from the rumen fermentation of Algerian Acacia tree foliage. Forage resources and ecosystem services provided by Mountain and Mediterranean grasslands and rangelands

4 páginas, 1 tabla.The present study was carried out to determine the in vitro methane production from the rumen fermentation of Acacia tree leaves (Acacia nilotica, A. cyanophylla, A. albida, A. horrida and Albizia julibrissin) and its reduction by the addition of a tannin-blocking agent (polyethylene glycol, PEG). Gas production was determined when foliage from the five plant species was incubated in diluted rumen fluid for 6, 12, 24 and 48 h, and methane was measured after the incubation at 24 h. The incubations were conducted either without or with the addition of the tannin binder polyethylene glycol (PEG-6000). This has been considered a bioassay of tannin activity, represented by the increase in gas (methane) production upon the addition of PEG (i.e., when tanning are neutralized). The ratio +PEG/-PEG (in total gas production) was highest for A. nilotica (2.23 and 1.75 at 12 h and 24h), followed by A. cyanophylla (1.73 at 48 h), reflecting the high amount and biologi - cal activity of tannins in these plants. PEG addition increased methane production for all the Acacia species, thus confirming that tannins in these samples affected methanogenesis. An increase in total volatile fatty acid concentration in samples with addition of PEG was observed only with A. nilotica and A. cyanophylla. Tannins contained in these plants could be of interest to reduce methane production, providing that other parameters of ruminal fermentation were not inhibited.Peer Reviewe

Nutritive evaluation of some browse plant species collected from Algerian arid rangelands by chemical analysis and in vitro gas production

6 páginas, 1 tabla, 1 figura.The objective was to evaluate the nutritive value of various Algerian browse and shrub species (Atriplex halimus, Artemisia campestris, Artemisia herba-alba, Astragalus gombiformis, Calobota saharae, Retama raetam, Stipagrostis pungens, Lygeum spartum and Stipa tenacissima). Chemical composition, and in vitro gas production kinetics for assessment of tannins using buffered rumen fluid were determined. Volume of gas (G) produced was recorded at several incubation times 3, 6, 9, 12, 16, 21, 26, 31, 36, 48, 72, 96, 120 and 144 h after inoculation time. France model G = A(1-e-c(t-L) ) was used to estimate the fermentation kinetics parameters. In general, protein content in dicotyledon species was always greater than in monocotyledon grasses, these showing higher NDF and ADF and lower lignin contents than dicots. The values of degradation coefficient (ED) are between 0.623 g/g DM for A. campestris and 0.126 g/g DM for S. tenacissima. After 144 hours of incubation time, the highest cumulative gas production was observed for S. pungens (269 ml/g DM) and the lowest was obtained by A. halimus (185 ml/g DM). The lowest in vitro digestibilities were observed in monocotyledons (being particularly low for S. tenacissima), whereas dicots had significantly higher values. The CP was not correlated to gas production at all kinetic points. Chemical composition (NDF and CP), in vitro 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 high nutritional value.Peer Reviewe