Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
Volume 18
Issue 2
Available Online: http://www.ejpau.media.pl/volume18/issue2/art-03.html


Samir Medjekal1, Mouloud Ghadbane2, Hacène Bousseboua3
1 Department of Applied Microbiology, University Mentouri of Constantine, Algeria
2 Department of Microbiology and Biochemistry, Faculty of Science, University of Mohamed Bouadiaf M’sila, Algeria
3 Ecole Nationale Supérieure de Biotechnologie Ville Universitaire Ali Mendjeli, Algeria



The current trial was conducted to study the effect of season on the potential nutritive value, methane production and condensed tannin of Calobota saharae shrub harvested at three different seasons, in winter (mid-January), spring (mid-May) and summer (end of July). Leaves, thin twigs, some flower and seeds (when existing) were clipped with scissors from the aerial part of the plants then dried and analysed for chemical composition. Gas and methane production were determined at 24 h incubation time. Season of harvest had a significant effect (p < 0.05) on the chemical composition, gas production and in vitro digestibility of Tilley and Terry but no effect on metabolisable energy. Neutral detergent fibre (NDF), Acid detergent fibre (ADF) and acid detergent lignin (ADL) of Calobota saharae were high during summer (dry season) and low in spring and winter (wet season). The NDF, ADF and ADL contents ranged from 463.05 to 616.82 and 352.27 to 488.21 and 121.19 to151.73 (g/kg DM) respectively. The CP content was lower (p < 0.05) in summer (96.84 g/kg DM) versus spring (138.85 g/kg DM) and winter (139.42 g/kg DM). The gas and methane production at 24 h incubation varied between 65.75 to 77.75 and 6.50 to 10.17 (ml/g DM) respectively and decreased significantly (p <0.05) from spring to summer. In conclusion, season had a significant effect on the nutritive value of Calobota saharae shrub. Calobota saharae should be grazed or harvested during winter and spring since these seasons provide this shrub with high ME and CP content for ruminant.

Key words: Calobota saharae, Condensed tannin, In vitro gas production, Nutritive value, Methane production, Rumen fermentation.


ADF (acid detergent fibre); ADL (acid detergent lignin); AOAC (Association of official analytical chemists); CP (crude protein); DM (dry matter); EE (ether extract);  FCT (fibre-bound condensed tannins); Free CT (free condensed tannins); GC (gas chromatography); GP24 (gas production 24hour); HCL (hemicellulose); IVD-TT (in vitro digestibility of Tilley and Terry); ME (metabolisable energy); NDF (neutral detergent fibre); PCT (protein-bound condensed tannins);  SDS (sodium dodecyl sulfate); TCT (total condensed tannins).


Large tracts of desert and semi-desert lands of African and Middle Eastern countries cannot be cultivated but can be used to raise livestock, mainly sheep, goats and camels. Even in favourable rainfall years, animal performance can be poor due to a lack of adequate dietary protein and energy intake in the dry season. Furthermore, the herbaceous forage is fibrous and of low quality, and in the event of drought, livestock mortality can be high [20]. Feed supplementation during drought is infeasible for livestock producers in resource-poor countries due to high feeding costs [6]. Thus, and alternative approach for overcoming such feed constraints is the propagation of nutrients local fodder shrubs on degraded land. One ligneous species suitable for browse in areas of severe aridity is Calobota saharae (Coss. & Durieu) Boatwr. & B-E. van Wyk (formerly  Genista saharae or  Spartidium saharae). Calobota have a great ecological significance in Mediterranean countries.

They colonize degraded forests and deforested areas that characterize the landscape [21]. The genus Calobota consisting of 87 species [26] among these species 23 grow in Algeria [24, 31]. The nutritive value of a ruminant feed is determined by the concentrations of its chemical components, as well as their rate and extent of digestion. Determining the digestibility of feeds in vivo is laborious, expensive, requires large quantities of feed, and is largely unsuitable for single feedstuffs thereby making it unsuitable for routine feed evaluation [12]. In vitro methods provide less expensive and more rapid alternatives. Both in vitro gas production and the ANKOM Technology (Automated instrumentation for the food analysis) devices can be used as rapid evaluation tools to assess nutritional quality of feeds [16]. In Algeria, there is limited information on the nutritive value of local shrubs and both in vitro and in vivo studies are not available. Moreover there is limited information on the impacts of seasonal variations on nutritional values of local most grazed leguminous shrub. A study was therefore carried out to evaluate the effects of season on chemical composition, in vitro gas production and organic matter degradability of indigenous shrub Calobota Saharae.


Collection of Calobota saharae
The study was carried out during 2009 in a medium-sized shrub-grassland between El Maader and Bousaada district located in the north central Algeria (N35° 26' 07,9''; E004°20'52,8'') (Fig. 1), at an altitude of about 398 m above sea. The area is an arid high plateau with steppe like plains and extensive barren soils. Its climate is continental, semi-arid, subjected partly to Saharan influences with an annual average temperature of 21°C (average temperature of 34°C in summer and 10°C in winter), and a low and irregular rainfall not exceeding 250 mmper year. M’Sila experiences high temperature between June and September, and rainfalls between September and December (Fig. 2).

Representative samples from the aerial parts of plants were randomly hand clipped with scissors along a transect of about 2 km, in winter (mid-January), spring (mid-May) and summer (end of July) during the year 2009. Between six and ten specimens of each plant species were sampled to obtain a representative aliquot of the edible biomass. Leaves, thin twigs (young stem) and some flower and seeds (when existing) were clipped with scissors from the aerial part of the plants, and taken immediately to the laboratory where the samples from different specimens were pooled, oven dried at 50°C [25], and subsequently ground to a 1 mm screen. 

Fig. 1. Location of the study areaion of the tarsocrural joint, characteristic of the third peroneal muscle rupture

Fig. 2. Precipitation and Temperature 2008–2010 (Tocyo Climate Center, http://ds.data.jma.go.jp/tcc/tcc/ )

Chemical composition and condensed tannins
Ash (Ash method ID 942.05), ether extract (EE, method ID 7.045) and crude protein by Kjeldhal (CP, method ID 984.13) in samples were determined by the procedures of the Association of Official Analytical Chemists [2]. Neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) contents were analysed following the methodology described by Van Soest et al. [38] using an ANKOM Model 220 Fibre Analyser (Macedon, NY, USA).

Levels of condensed tannins of each sample were determined using the method described by Terrill et al. [34]. Free tannins are estimated by HCL-butanol, after the extraction of this fraction with diethyl ether to remove lipids and interfering pigments. The residue from the acetone extraction is treated with sodium dodecyl sulfate (SDS) and the extract obtained reacts again with HCl-butanol assay protein bound tannins. After SDS extraction the remaining residue is also treated with HCL-butanol to assay fibre-bound condensed tannins [4]. Solution of purified quebracho tannin (1 mg/ml aqueous acetone, 700 ml/l) was the standard. Absorbance was measured against a blank at 550 nm. The CH4 concentration was determined by gas chromatography (GC) using a HP Hewlett 5890, Packard Series II gas chromatograph (Waldbronn, Germany). A sample of 0.5 ml of gas was injected using a 1 ml Sample-Lock® syringe (Hamilton, Nevada, USA).

In vitro gas production (GP24h), In vitro dry matter digestibility of Tilley and Terry (IVD-TT) and metabolizable energy (ME) MJ/kg
Four adult and mature Merino sheep (body weight 48.3±3.45 kg) fitted with a permanent ruminal cannula were used for the extraction of rumen fluid to carry out the in vitro incubations (gas production and digestibility) of the browse material. Animals were fed twice a day (9 a.m. and 4 p.m.) a diet that consisted of alfalfa hay and grain oats in a proportion 60:40 at approximately and had free access to water and mineral/vitamin licks. A sample of rumen contents was withdrawn prior to morning feeding. Of each of the animals takes a similar amount of rumen contents, which is transferred into thermos flasks and taken immediately to the laboratory. Animals were cared for by trained personnel in accordance with the European Convention for the Protection of Vertebrates used for Experimental and other Scientific Purposes [10]. Rumen fluid from the four sheep was mixed, strained through various layers of cheesecloth and kept at 39°C under a CO2 atmosphere. Batch cultures of mixed rumen micro-organisms were used to study the ruminal fermentation, gas and methane production. The experimental procedure was based on Theodorou et al. [34] protocol with some modifications. Three identical 48 h incubation runs were carried out in three consecutive weeks. The buffer solution of Goering and Van Soest [13], (1970) was previously prepared into an Erlenmeyer flask under a CO2 stream and kept one hour with an O2-free headspace after the resazurine color turnover showed an O2-free solution. Particle-free ruminal fluid was mixed with the buffer solution in a proportion 1:4 (vol/vol) at 39°C under continuous flushing with CO2. Buffered ruminal fluid (50 mL) was added into each bottle under CO2 flushing. Bottles were sealed with butyl rubber stoppers and aluminum caps and placed in a water bath at 39°C. Serum bottles of 120 mL were used. In each incubation run triplicate samples (0.5 g dry matter, DM) were placed into the bottle and incubated. Pressure in the bottle headspace and volume of gas produced were measured at 24 inoculation using a Wide Range Pressure Meter (Spec Scientific LTD, Scottsdale, AZ, USA) and a calibrated glass syringe as described by Theodorou et al. [35] respectively. An aliquot of the gas produced was taken in a 10 mL vacuum tube (Venoject®, Terumo Europe N.V., Leuven, Belgium) for CH4 concentration analysis. Fermentation flasks without samples (i.e., blanks) were included to allow correction for gas produced directly from rumen fluid.

Analysis of in vitro dry matter (DM) digestibility (IVD-TT) followed the method of Tilley and Terry [36]. A culture medium containing macro- and micro-mineral solutions, resazurin and a bicarbonate buffer solution was prepared as described by Van Soest et al. [39]. Rumen fluid was then diluted into the medium in the proportion 1:5 (v/v). Samples (400 mg) were weighed out into artificial fibre bags (size 5 × 5 cm, pore size 20 m) which were sealed with heat and placed in incubation jars. The jars were then placed in a revolving incubator (Ankom Daisy II digestion system, ANKOM Technology Corp., Fairport, NY, USA) at 39°C, with continuous rotation to facilitate the effective immersion of the bags in the rumen fluid. After 48 h of incubation in buffered rumen fluid, samples were subject to a 48 h pepsin-HCl digestion as described by Tilley and Terry [36].

ME [MJ/kg DM] content of Calobota saharae samples was calculated using equation of Menke et al [27] as follows:

ME [MJ/kg DM] = 2.20 + 0.136 GP + 0.057 CP,

GP = 24 h net gas production [ml/200 mg];
CP = Crude protein.

All data obtained were subjected to analysis of variance (ANOVA) using the randomized completed block design. Significance between individual means was identified using the Tukey’s multiple range tests. Mean differences were considered significant at P < 0.05. Analysis of variance (PROC ANOVA) was performed using the SAS software package [32].


The changes in chemical composition of Calobota saharae at different seasons of harvest are presented in Table 1. There were differences between growth seasons in ash, cell wall components, CP, EE and condensed tannins contents (p < 0.05). The CP content was lower in summer (96.84 g/kg DM) versus spring (138.85 g/kg DM) and winter (139.42 g/kg DM). In winter, Calobota saharae had lower (p < 0.05) NDF, ADF, ADL and HCL content than in summer, and intermediate values were observed in spring. In the other hand, high values of ash, EE and CTC were observed during spring versus summer and winter with values ranging between 3.92 and 5.44, 20.64 and 23.79 and 25.33 and 34.72 g/kg DM respectively.

The 24h volume of gas produced (GP24), methane (CH4 24h) in vitro digestibility of Telly and Terry in each season are in Table 2. There are marked decreases in gas production, methane and IVD-TT from spring to summer.

Table 1. Chemical composition and condensed tannins [g/kg DM] contents of Calobota saharae harvested at three different seasons (n = 6) for all chemical parameters.
Free CT
a, b, c Row means with common superscripts do not differ (P<0.05);
S.E.M.: standard error mean; Ash: Ash %; NDF: Neutral detergent fiber, ADF: Acid detergent fiber, ADL: Acid detergent lignin, HCL: Hemicellulose, CP: Crude protein, EE: Ether extract, Free CT: Free  condensed tannins, PCT: Protein-bound condensed tannins, FCT: Fibre-bound condensed tannins, TCT: Total condensed tannins;
*** – P < 0.05

Table 2. Gas production (GP24 [ml/g DM] methane 24h [ml/g] in vitro digestibility [%] and metabolic energy [MJ/KG DM]; n = 3 for all parameters)
Estimate parameters
GP24h [ml/g]
CH4 24h [ml/g]
IVD-TT [%]
a, b, c Row means with common superscripts do not differ (P<0.05);
standard error mean; GP24: gas production 24hour [ml/g], CH4: methane production 24 hour [ml/g], IVD-TT: in vitro  digestibility of Tilley and Terry [%], ME: Metabolisable energy [MJ/KG DM], NS: Non-significant


In the current study, large differences in the nutritive value of Calobota saharae (as assessed by gas production and DM degradability) were observed, which were primarily the results of changes in maturity of the collected leaves. Reduction (p < 0.05) in CP content of Calobota saharae in summer versus other seasons, is consistent with other studies, as was the observation that the minimum CP content of fodder tree leaves in the dry season was more than twice that of grasses in the wet season [9, 33]. However, the CP content of Calobota saharae remained relatively high (96.84 g/kg DM) during summer which is higher than the minimum level of 7–8 % DM required for optimum rumen function and feed intake in ruminants livestock [40]. In addition, the higher CP content (193.42 g/kg DM) during winter compared with the other two seasons as a result of higher moisture content and nitrogen uptake being more rapid than dry matter accumulation agrees with [3, 19] who reported that seasonal variation occur between plant species and between seasons with higher values reported for seasons with higher moisture levels. The lower CP content during summer may be largely due to moisture stress experienced by Calobota saharae during this period and build-up of lignocellulosic fibre structures of the plants, diluting the nitrogen [1]. The wide variations in NDF, ADF, ADL and HCL contents of Calobota saharae in winter and summer are consistent with the report of Onwuka et al. [30], on browse species in the humid lowlands of West Africa and in other parts of the tropics [8, 37]. The seasonal differences in cell wall constituents may relate to the differences in elements of the weather between seasons, and their effects on cell wall lignifications as well as translocation of nutrient to the different part of the plant [18]. Moreover, cell wall concentration in shrub fodder is negatively correlated with palatability [14, 18]. Therefore, the observed differences in NDF, ADF, ADL and HCL among the seasons of harvest could have implications for the use of Calobota saharae as a fodder. Condense tannin had an important role in forages depending on the amount. Low level tannin (2–3% of DM) may have beneficial effect since the level of tannin in diets prevents the CP from extensive degradation through formation of protein-tannin complexes [5]. In addition, condensed tannins in fodder trees and shrubs could also, help in the control of gastro intestinal parasites because they have biological properties that decrease fecal egg count in sheep and goats, and hatch rate and Laval development in feces [29]. On the other hand, high tannin level (5% of DM) in diets may result in the increased indigested CP due to excessive formation of tannin-protein complexes [17]. As can be seen from Table 1, the observed condensed tannin levels of Calobota saharae harvested at three different seasons were low magnitude. Therefore, low condense tannin of Calobota saharae seems to have a potential for beneficial effect when included into ruminant diet as it can increase rumen undegradable CP without decreasing digestibility [23]. The gas production is closely associated with the amount of fermented substrate in diets [7]. The low gas production for Calobota saharae in the dry season (summer) may be attributed to the relatively higher NDF, ADF, ADL and the low CP content. Our observation are similar to Evitayani et al. [9], who found that in vitro gas production and in vitro dry matter digestibility of some legume species increased in wet season (winter) compared with the dry season (summer).  Similar observations with maturity were also observed by kamalak et al. [15] in Gundelia tournifortii hay and Mahmut et al. [23] in Sanguisorba minor hay. There were no differences in ME of Calobota saharae obtained in the current study this could be due to the little variations of gas production between the three seasons, since, ME energy values were estimated using the gas production and CP content. According to Fagg and Stewart [11], indigenous legumes of arid regions such as Calobota saharae, because of their nitrogen fixing symbiosis with legume nodulating bacteria, collectively called rhizobia, contribute to soil fertility by enhancing soil nitrogen content and organic matter. They provide high-quality animal fodder, prevent erosion and contribute to soil stabilization and ecosystem restoration.

Methane is a product of microbial fermentation, particularly in the rumen. At the end of a complex interplay of microbiological and chemical processes, methanogens use hydrogen to reduce carbon CO2 to CH4 [28]. Lopez et al. [22] suggested that the methane reduction potential of any feedstuffs can be estimated from the percentage of methane of in vitro gas production and the feedstuffs can be arbitrarily divided in three groups, low potential (% methane in gas between >11% and ≤14%), moderate potential (% methane in gas between >6% and <11%), high potential (% methane in gas between >0% and <6%). Therefore, Calobota saharae, shrub had no methane reduction potential since the percentage of methane for all the seasons is between 10 to 13%. The recent interest in methanogenesis reflects effects to identify mitigation strategies to reduce output of this greenhouse gas from livestock and manure. It also reflects an interest in reducing a source of energy loss that arises when feed is digested by ruminants.


The results presented in this study indicate that the major differences in nutritive value of Calobota saharae shrub, in terms of chemical composition and rumen microbial fermentation, are caused by the effect of the growing season. Calobota saharae should be grazed or harvested during winter and spring since these season provides this shrub with high ME and CP content for ruminant. This study has practical implications for the development of agro-forestry technologies. Calobota saharae shows potential as a fodder shrub for revegetation projects in degraded ecosystems in arid and semiarid lands.


  1. Anele U.Y., Arigbede O.M., Südekum K.H., Oni, A.O., Jolaosho A.O., Olanite J.A., Adeosun A.I., Dele P.A.,  Ike K.A.,  Akinola O.B., 2009. Seasonal chemical composition, in vitro fermentation and in sacco dry matter degradation of four indigenous multipurpose tree species in Nigeria. Anim. Feed Sci.Technol., 154, 47–57.
  2. AOAC, 2005. Official Methods of Analysis of AOAC International, 18th ed. Gaithersburg, Maryland 20877–2417, USA.
  3. Bamualim A., Jones R.J., Murray R.M., 1980. Nutritive value of tropical browse legumes in the dry season. Proc. Aust. Soc. Anim. Prod., 13, 229–232.
  4. Barahona R.R., 1999. Condensed tannins in tropical forage legumes: their characterization and study of their nutritional impact from the standpoint of structure-activity relationships. Ph.D. Thesis. Department of Agriculture, the University of Reading.
  5. Barry T.N., 1987. Secondary compounds of forages. In: Nutrition of Herbivores, Hacker J-B, Ternouth J-H. (Eds). Academic Press, Sydney, 91–120.
  6. Benavides J.E., 1994. La Investigacion en Arboles Forrajeros. Arboles y Arbustos Forrajeros en America Central, CATIE, Turrialba, Costa Rica., 1, 3–28.
  7. Blummel M., Orskov E.R., 1993. Comparison of an in vitro gas production and nylon bag degradability of roughages in predicting feed intake in cattle. Anim. Feed Sci. Technol., 40, 109–119.
  8. Dzowela B.H., Hove L., Topps J.H., Mafongoya P.L., 1995. Nutritional and anti-nutritional characters and rumen degradability of dry matter and nitrogen for some multi-purpose tree species with potential for agroforestry in Zimbabwe. Anim. Feed Sci.Technol., 55, 207–214.
  9. Evitayani Warly L., Fariani A., Ichinohe T., Abdulrazak S.A., Fujihara T., 2004. Comparative rumen degradability of some legumes forages between wet and dry seasons in west Sumatra, Indonesia. Asian-Aust. J. Anim. Sci., 17, 1107–1111.
  10. European Directive 86/609. Commission recommendations of 18 June 2007 on guidelines for the accommodation and care of animals used for experimental and other scientific purposes. Annex II to European Council Directive 86/609. The Commission of the European Communittes Publishing, Brussels, Belgium.
  11. Fagg C.W., Stewart J.L., 1994. The value of Acacia and Prosopisin arid and semi-arid environments. J. Arid. Environ., 27, 3–25.
  12. Getachew G., De Peters E.J., Robinson P.H., 2004. In vitro gas production provides effective method for assessing ruminant feeds. California Agriculture, 58, 1–12.
  13. Goering H.K., Van Soest P.J., 1970. Forage fiber analysis (Apparatus, reagent, procedures and some applications). Agric. Handbook, No. 379, ARS-USDA. Washington, DC.
  14. Kaitho R.J., Nsahlai I.V., Williams B.A., Umunna N.N., Tamminga S., Van Bruchen J., 1997. Relationship between preference, rumen degradation, gas production and chemical composition of browses. Agrofor. Syst., 39, 129–144.
  15. Kamalak A., Canbolat O., Gurbuz Y., Erol A., Ozay O., 2005.  Effect of maturity stage on chemical composition, in vitro and in situ dry matter degradation of tumbleweed hay (Gundelia   tournefortii  L).  Small Rumin Res., 58, 149–156.
  16. Khanal R.C., Subba D.B., 2001. Nutritional evaluation of leaves from some major fodders trees cultivated in the hills of Nepal. Anim. Feed. Sci. Technol., 92, 17–32. 
  17. Kumar R., Singh M., 1984. Tannins: Their adverse role in ruminant nutrition. J. Agric. Food Chem., 32, 447–453.
  18. Larbi A., Smith J.W., Kurdi I.O., Adekunle I.O., Raji A.M., Ladipo D.O., 1998. Chemical composition, rumen degradation and gas production characteristics of some fodder tree and shrubs during wet and dry season in the humid tropics. Anim. Feed Sci. Technol., 72, 81–96.
  19. Larbi A., Smith J.W., Raji A.M., Kurdi I.O., Adekunle I.O., Ladipo D.O., 1997. Seasonal dynamics in dry matter degradation of browse in cattle, sheep and goats. Small Rumin. Res., 25, 129–140.
  20. Le Houérou H.N., 1980. Planting and management methods for browse trees and shrubs. In: Browse in Africa, the current state of knowledge, Le Houérou, H.N. (Eds). UNESCO, Paris France, 351–359.
  21. Lopez Gonzalez G.A., 2001. The trees and Shrubs in the Iberian Peninsula and Balearic Islands: (Wild and the Main Cultivated Species). 2nd Edn., Mundi-Prensa, Madrid, Spain, ISBN: 84-7114-953-2, 1511–1518.
  22. Lopez S., Makkar H.P.S., Soliva C.R., 2010. Screening plants and plant products for methane inhibitors. In: In vitro  Screening of Plant Resources for Extra-nutritional Attributes  in Ruminants: Nuclear and Related Methodologies, Vercoe P.E., Makkar H.P.S., Schlink A., (Eds). London, New York, 191–231.
  23. Mahmout K., Kamalak A., Kzsra A.A., Guven İ., 2014. Effect of Maturity Stages on Potential Nutritive Value, Methane Production and Condensed Tannin Content of Sanguisorba minor Hay. Kafkas Univ Vet Fak Derg., 20, 445–449.
  24. Maire R., 1987. Flore de l’Afrique du Nord. Vol. 16, Le chevalier, Dicotyledonae, Paris, ISBN 2-7205-0519-6, pp: 302.
  25. Makkar H.P.S., 2003. Quantification of Tannins in Tree and Shrub Foliage. Kluwer Academic Publishers. Dordrecht (The Netherlands).
  26. Martin A., Wink M., Tei A., Brum-bousquet M., Tillequin F., Rauter A.P., 2005. A phytochemical study of the quinolizidine alkaloids from Genista tenera by gas chromatograpghy-mass spectrometry. Phytochem Anal., 16, 264–266.
  27. Menke K.H., Raab L., Salewski A., Steingass H., Fritz D., Schneide, W., 1979. The estimation of the digestibility and metabolizable energy content of ruminant feedingstuffs from the gas production when they are incubated with rumen liquor in vitro. J. Agric. Sci. (Camb)., 93, 217–222.
  28. Mills J.A.N., Dijkstra J., Bannink A., Cammell S.B., Kebreab E., France J.P., 2001. A mechanistic  model  of   whole-tract  digestion  and   methanogenesis  in   the lactating  dairy  cow:  model  development,  evaluation,  and   application. J. Anim. Sci., 79, 1584–1597.
  29. Min B.R., Hart S.P., 2003. Tannins for suppression of internal parasites. J. Anim. Sci., 81, E102–E109.
  30. Onwuka C.F.I., Akinsoyinu A.O.O., Tewe O.O., 1989. Feed value of some Nigerian browse plants: chemical composition and in vitro digestibility of leaves. E. Afr. Agric. For J., 54, 157–163.
  31. Quezel P, Santa S., 1962. Nouvelle flore de l’Algérie et des régions désertiques Méridionales. CNRS, Paris.
  32. SAS., 2002. SAS User’s Guide: Statistics. Ver 9.0. SAS Institute. Cary, NC.
  33. Skarpe C., Bergstrom R., 1986. Nutrient content and digestibility of forage plants in relation to plant phonology and rainfall in the Kalari, Botswana. J. Arid Environ., 11, 147–164.
  34. Terrill T.H., Rowan A.M., Douglas G.B., Barry T.N., 1992. Determination of extractable and bound condensed tannin concentrations in forage plants, protein concentrate meals and cereal grains. J. Sci. Food Agric., 58, 32, 1–329.
  35. Theodorou M.K., Williams B.A., Dhanoa M.S., McAllan A.B., France J.P., 1994. A simple gas production method using a pressure transducer to determine the fermentation kinetics of ruminant feeds. Anim. Feed Sci. Technol., 48,185–197.
  36. Tilley J.M.A., Terry R.A., 1963. A two-stage technique for the in vitro digestion of forage crops Current Contents. J. Bt. Grass. Soci., 18, 104–111.
  37. Topps J.H., 1992. Potential, composition and use of legume shrubs and trees as fodder for livestock in the tropics (a review). J. Agric. Sci. (Camb)., 118, 1–8.
  38. Van Soest P.J., Robertson J.B., Lewis B.A., 1991. Methods for dietary fibre, neutral detergent fibre and non-starch polysaccharides in relation to animal nutrition. J. Dairy. Sci., 74, 3583–3597.
  39. Van Soest P.J., Wine R.H., Moore L.A., 1966. Estimation of the true digestibility of forage by the in vitro digestion of cell walls. Proc. 10th Int. Grassl Cong., 10, 438–441.
  40. Van Soest P.J., 1994. Nutritional Ecology of the Ruminant. Cornell University Press, Ithaca, NY, USA.
Accepted for print: 11.04.2015
Samir Medjekal
Department of Applied Microbiology, University Mentouri of Constantine, Algeria
BP 360,
route de Ain El-Bey
25.017 Constantine
email: sammedj2008@gmail.com

Mouloud Ghadbane
Department of Microbiology and Biochemistry, Faculty of Science, University of Mohamed Bouadiaf M’sila, Algeria
28 000 M’sila

Hacène Bousseboua
Ecole Nationale Supérieure de Biotechnologie Ville Universitaire Ali Mendjeli, Algeria
B.P. E66

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