Seasonal variations in the chemical composition and nutritional characteristics of three pastoral species from Algerian arid rangelands

R Mayouf and F Arbouche¹

Department of Agronomy, Faculty of Sciences, Hadj Lakhdar University, Batna 05000, Algeria
rabahmayouf@gmail.com
¹ Laboratory of Agriculture and Ecosystem Functioning, Faculty of Sciences, El-Tarf University, El-Tarf, 36000, Algeria

Abstract

The main objective of this study was to determine the quality of the pasture in the arid region of Algeria. Three dominant shrubs ( Haloxylon schmittianum, Anabasis articulata and Astragalus armatus) were analyzed to characterize the chemical properties, in vitro organic matter digestibility and nutritional value. Samples were collected during a period of one year (from December 2011 to November 2012) to evaluate the variations in the chemical composition and nutritional characteristics between the dry and wet seasons.

Results showed that the three species differed significantly in their nutrient composition in both seasons except for the Ash and organic matter (OM) which did not differ between seasons. Crude protein (CP) and neutral detergent fiber (NDF) differed significantly between species and among the seasons. The Crude protein (CP) content of the browse species was higher in the wet season compared to dry season, A. Articulata had the highest values (173 and 112 respectively), the lowest forA. armatus (126 and 85 respectively). The NDF values ranged between 417 in H. schmittianum and 446 in A. armatus for the wet season while for the dry season on DM basis, the values ranged from 429 to 491 in H. schmittianum and A. armatus, respectively.In vitro Organic matter digestibility (IVOMD), digestible organic matter (DOM) and estimated net energy (NE) varied significantly between species and seasons, H. shmittianum had the highest values during the both seasons, while A. armatus had the lowest values. Generally, apart from the differences among species within a same season, for each species, there was a significant difference in nutrient composition between the dry and wet season. The present study showed that the three fodder shrubs had a good nutritive value for wet season feed, while A. armatus require a supplementation of nitrogen for dry season. However, further research is needed to assess the changes on the nutritional value of pastoral shrubs at different phenological stages

Key words: in vitro digestibility, nutritive value, season, semiarid, shrubs

Introduction

In the natural pastures of Algerian steppe, the forages browsed by the livestock can be classified into two main groups; ephemeral annual plants which germinate and growth for only a few weeks after raining, and perennial shrubs and tree fodders. The diversity and relative abundance of fodder plants has allowed the steppe to provide animal food for 15% of the Algerian population, and represents the main source of red meat for the population as a whole (Aidoud 1994). The quality of nutrition is a key factor of any ruminant that wants efficient. They must receive all the essential dietary nutrients in optimal amounts. However, several factors are involved, and largely responsible for situations deficiencies as: intensification of farming, climate instability, fertilization, soil characteristics that influence the bioavailability of these nutrients. In arid and semi-arid regions of eastern Algeria, the food situation is characterized in ruminants by insufficient forage offers both quality and quantity. Field farming is especially extensive. The diet of these animals is formed by a spontaneous annual vegetation of natural pastures, fallow and by residues from agriculture.

Trees and shrubs play an important role in ruminant feeding systems in semiarid areas. Studies on some fodder shrubs from Algerian semiarid regions have shown a positive effect on the performance of animal. Therefore, evaluation of the nutritive value of species, commonly used as feed resources, would be important to intensify their utilization (Haddi et al 2009). However, in Algeria, studies related to the ingestion and digestion in ruminant on semi-arid areas rangelands are relatively recent (Haddi et al 2009; Arhab et al 2009; Boufennara et al 2012; Bouazza et al 2012). Such research should be continued to develop appropriate methods for the estimation of the average intake and digestibility taken vegetation during the year to share periods of complementation for the safeguarding and/or improve the production of this species. In the other hand, this could encourage farmers that are responsible for rational and sustainable management of the rangelands to preserve this threatened area from desertification (Ben Arfa et al 2004). Therefore, the aim of this work was to study the chemical composition, in vitro organic matter digestibility and nutritive value of three important fodder species in a arid area of Algeria. This area was selected in this study as a good model of Algerian steppes because the browse constitutes the major food resource for goats, camels and sheep in this region.

Materials and Methods

Description of the study site

The study site is an arid zone and was located on the southeast of Algeria, region of Tebessa (34°28’59’’ N and 7°31’0’E). The trial was carried out during a period of one year (December 2011 to November 2012). This region is characterized by altitude level of 316 m, with a typical Mediterranean climate. The coldest month is December, with occasional freezing (down to -2°C) in January and February. The period between July and August is the hottest, sometimes extremely hottest, during which temperatures can reach as high as 46°C (in the shade). The rainfall is characterized by low averages, high irregularity and torrential downpours. Generally, the region receives between 100 and 300 mm per year. Samples were collected from the pastures every first week of each month.

Chemical analysis

Before analyses, the samples were dried for 48 h at 60°C and then, the samples were weighed and ground in a hammer mill, provided with a 1 mm pore size screen. The chemical analysis of plants was performed according to the methods of the Association of Official Analytical Chemists (AOAC 1990). The dry matter (DM) content of plants was determined by drying to constant weight at 105°C, and ash after heating at 550°C until a constant weight has been reached. In this analysis, the following contents: organic matter, crude protein (CP = 6.25 × nitrogen), ether extract (EE), nitrogen free extract (NFE) were analyzed according to standard methods (AOAC 1990), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) were determined according to (Van Soest et al 1991). Organic matter in vitro digestibilities of samples was determined by the method (Aufrere 1982). Based on digestible organic matter (DOM) content of forages, metabolizable energy (ME, MJ kg−1 DM) content of the shrubs was estimated according to (MAFF 1984) equation (ME = DOM% X 0.015). The net energy for lactation (NE) content was calculated using the ratio NE/ME = 0.60 (Sauvant and Morand-Fehr 1991), where ME is the metabolizable energy content of the feed.

Statistical analysis

Different experimental groups (constituents and parameters) were compared with the Univariate ANOVA followed by Bonferroni’s test for comparisons post hoc. A probability level of P≤0.05 was considered to be statistically significant. The SPSS software package (SPSS Ver. 15.0, SPSS Inc., Chicago, Illinois) was used for all tests.

Results and discussion

Chemical compositions of shrubs samples are shown in Table 1. The dry matter contents ranged from 721.1±1.0 g/kg DM for A. articulata to 834.0±2.5 g/kg DM for A. armatus in wet season. While in the dry season, the DM content was 894.7±3.1 g/kg DM in H. schmittianum and 910.7±2.0 g/kg DM in A. armatus (Table 1). The DM concentrations recorded for the three shrubs in this study were within the ranges reported by Bouazza et al (2012) under similar conditions in Algerian arid and semi-arid areas. All the shrubs contained sufficient DM to support a reasonable amount of DM intake.

The present study showed that the dry matter contents of our shrubs were influenced by seasons and species. This is because dry season values were significantly higher (P<0.05) than those of wet season.

The ash content varied from 114 g/kg DM to 198 g/kg DM in the dry season, whereas in the wet season, varied from 108 g/kg DM to 191, this result was compared than the values reported by Arhab et al (2009). Ash concentrations differed (P<0.05) between species; but seasonal effect was not observed. The high value of Ash could be attributed to the climate effect and especially to the high temperatures and the sand accumulation on the aerial part of the plant.

The crude protein (CP) content of the browse species ranged from 85 g/kg DM in A. armatus to 112 g/kg DM in A. articulata during the dry season. Corresponding values for wet season ranged from 126 to 173 g/kg DM in A. armatus and A. articulata, respectively (Table 1). The CP values were similar to those reported for other Mediterranean shrubs (Arhab et al 2009; Ammar et al 2004).

Additionally, the CP content of the three species was higher in the wet season than in the dry season (P<0.05). This was consistent with previous studies that conducted in areas with distinct wet and dry seasons (Safari et al 2010; Yayneshet et al 2009, Hassen et al 2007). The protein content decreased with advancing dry season for the three shrub species. This decline in nutrient contents could be related to the stage of maturity (Rawnsley et al 2002). Mero and Udén (1998) have reported that the levels of protein at young stages of plant growth are usually high; at the end of vegetative stage achieve the maximum values and declining as plants matured.

The CP content of the shrub species studied herein is higher, mainly in the wet season, than the minimum level of 7 to 8% DM required for optimum rumen function and feed intake in ruminant livestock (Van Soest 1994). This suggested that fodder shrubs can support maintenance requirements and certain level of production in ruminants.

The NDF content varied between species and seasons (P<0.05). The highest NDF content was recorded for A. armatus in the dry and wet seasons (491 and 446 g/kg DM, respectively) while H. schmittianum had the lowest values in both seasons (429 and 417 g/kg DM). In the dry season, the lowest ADF content was recorded in A. articulata (258 g/kg DM) while the highest value was recorded in A. armatus (328 g/kg DM) . In the wet season, H. schmittianum had the lowest ADF content (417 g/kg DM) while A armatus had the highest (300 g/kg DM). The values of ADL ranged from 56 g/kg DM in H. schmittianum to 86 g/kg DM in A articulata in the dry season, but in the wet season, ADL ranged from 91 g/kg DM in A articulata to 98 g/kg DM in A armatus (Table 1). A. armatus had relatively higher NDF, ADF, than A. articulata and H. schmittianum. The NDF level of A. armatus was higher than that reported for other browse species during the dry season in eastern Algeria by Bouazza et al (2012), but was lower than reported by Arhab et al (2009). Differences in NDF may be related to proportion of leaf and twigs in samples used for chemical analysis. The ADL levels were within ranges reported for some browse plant species in Algeria (Boufennara et al 2012).

The IVOMD (Table 2), varied significantly between species and seasons. During the wet season, IVOMD varied from 56 % in H. shmittianum to 40 % inA. armatus. During dry season, IVOMD ranged between 48 % in H. shmittianum and 32 % in A. armatus. It is important to note that H. shmittianum had the highest IVOMD in both season followed by A. articulata. For the DOM contents, H. shmittianum had the highest values in the dry and wet season, 422 and 485 g DOMkg^-1DM respectively, hawever A. armatus had the lowest values, 261 and 330 g DOMkg^-1DM.

IVOMD and DOM content of the three shrubs were lower than those found by Ventura et al (2004) and similar to those found by Kokten et al (2010) for other Mediterranean shrubs. Other researchers (Rogosic et al 2006, Mokoboki et al 2005) have reported values lower than that of H. shmittianum and A. articulata, but higher than that of A. armatus. Considering the estimated net energy content of shrubs (Table 2), values had a significant difference among species and seasons. The lowest content was recorded for A. armatus in the dry and wet seasons (2 and 3 g/kg DM, respectively) while H. schmittianum had the highest values in both seasons (3 and 4 g/kg DM). The NE content (Table 2) of these shrubs was higher than that estimated by Bovolenta et al (2008) and Rogosic et al (2006), with the highest contents in wet season. Between wet and dry season, it was observed increases in Ash, NDF and ADF, while CP and EE declined. This causes a reduction in OMD and a decline in NE.

Conclusion

• The common shrubs (H. schmittianum, A. articulata and A. armatus) which constitute the basic diet for ruminants in the region of Tebessa are medium in CP and this account for part of the low productivity of animals, especially during the dry season. For all studied shrubs, nutrient levels fluctuated with season, but the degree of fluctuation varied with species. The greatest variations in nutrient levels occurred in A. armatus, while the least variation occurred in H. schmittianum. In addition, A. armatus had the lowest nutritive value during the dry season because of its high lignin and low CP levels. The potential nutritive value of each shrub species may not be uniform throughout the year due to climatic and edaphic variations. It could be suggested that, although our browse species provide a part of animals demand for energy, protein and macro-minerals to overcome the negative impact of the dry season, additional protein sources should be supplied during the dry season in order to cover the needs of preservation of grazing animals. Furthermore rational range management techniques are required to elevate the quality and quantity of grazable material and maintain the traditional pastoralism of these landscapes.

References

Aidoud A 1994 Pâturage et désertification des steppes arides en Algérie, Cas de la steppe d’alfa (Stipa tenacissima L). Paralelo 37, 16, 33-42.

Ammar H, Lopez S, Gonzalez J S and Ranill M J 2004 Seasonal variations in the chemical composition and in vitro digestibility of some Spanish leguminous shrub species. Animal Feed Science and Technology 115, 327-340.

AOAC 1990 Official Methods of Analysis, Association of Analytical Chemists. Arlington, VA.

Arhab R, Macheboeuf D, Aggoun M, Bousseboua H, Viala D and Besle J M 2009 Effect of polyethylene glycol on in vitro gas production and digestibility of tannin containing feedstuffs from North African arid zone. Tropical Subtropical Agroecosyst 10, 475-486.

Aufrère J 1982 Etude de la prévision de la digestibilité des fourrages par une méthode enzymatique. Annales de zootechnie 31, 111-130.

Bouazza L, Bodas R, Boufennara S, Bousseboua H and López S 2012 Nutritive evaluation of foliage from fodder trees and shrubs characteristic of Algerian arid and semi-arid areas. Journal of Animal and Feed Sciences 21, 521–536.

Boufennara S, Lopez S, Bousseboua H, Bodas R and Bouazza L 2012 Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands. Spanish Journal of Agricultural Research 10(1), 88-98.

Ben Arfa A, Khorchani T, Hammadi M, Chammem M, El-Hatmi H, El-Jeni H, Abdouli H and Cheniti T L 2004 Digestibilité et ingestion de la végétation d'un parcours d'halophytes par le dromadaire dans le Sud tunisien, Proceedings of Réhabilitation des pâturages et des parcours en milieux méditerranéens, Rangeland and pasture rehabilitation in Mediterranean areas, (A Ferchichi Eds), (CIHEAM-IAMZ, Zaragoza, Spain), 301–305.

Bovolenta S, Spanghero M, Dovier S, Orlandi D and Clementel F 2008 Chemical composition and net energy content of alpine pasture species during the grazing season. Animal Feed Science and Technology 146:178-191.

Haddi M L, Arab H, Yacoub F, Hornick J L, Rollin F and Mehennaoui S 2009 Seasonal changes in chemical composition and in vitro gas production of six plants from Eastern Algerian arid regions. Livestock Research for Rural Development, Volume 21 Article 4, from www.lrrd.org/lrrd21/4/hadd21047.htm

Hassen A, Rethman N F G, Van Niekerk W A and Tjelel T J 2007 Influence of season/year and species on chemical composition and in vitro digestibility of five Indigofera accessions. Animal Feed Science and Technology 92, 149–158.

Kokten K, Gursoy O, Tukel T and Hatipoglu R 2010 Yield and Nutritive Value of Anti-Taurus Mountain Rangeland Shrubs in Turkey. Journal of Animal and Veterinary Advances, 9: 716-720, from http://medwelljournals.com/abstract/? doi=javaa.2010.716.720

Maff 1984 Energy allowances and feeding systems for ruminants. Reference Book 433, Ministry of Agriculture, Fisheries and Food, London.

Mero R N and Udén P 1998 Promising tropical grasses and legumes as feed resources in central Tanzania, Nitrogen balance in growing bulls consuming tropical herbaceous forage legumes. Animal Feed and Science Technology 72, 387–396.

Mokoboki H K, Ndlovu L R, Ng’ambi J W, Malatje M M and Nikolova RV 2005 Nutritive value of Acacia tree foliages growing in Limpopo province of South Africa. South Africa Journal of Animal Science 35(4): 221-228.

Rawnsley R P, Donaghy D J, Fulkerson WJ and Lane PA 2002 Changes in the physiology and feed quality of cocksfoot (Dactylis glomerata L.) during regrowth. Grass Forage Science 57, 203–211.

Rogosic J, Pfister J A, Provenza F D and Grbesa D 2006 Sheep and goats Preference for and Nutritional Value of Mediterranean Maquis Shrubs. Small Ruminant Research, Volume 64, 169-179.

Safari J, Mushi D E, Kifaro G C, Mtenga L A and Eik L O 2011 Seasonal variation in chemical composition of native forages, grazing behaviour and some blood metabolites of Small East African goats in a semi-arid area of Tanzania. Animal Feed Science and Technology 164 (1-2): 62-70

Sauvant D and Morand-Fehr P 1991 Energy requirements and allowances of adults goats. In: Morand-Fehr P, (Ed) Goat Nutrition, PUDOC, Wageningen, pp, 61–72.

Van Soest P J 1994 Nutritional Ecology of the Ruminant, Cornell University Press, Ithaca, NY.

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fiber, neutral detergent fiber and non-starch polusaccharides in relation to animal nutrition. Journal of Dairy Science 74, pp. 3583–3597.

Ventura M R, Castanon J I R, Pieltain M C and Flores M P 2004 Nutritive value of forage shrubs: Bituminaria bituminosa, Rumex lunaria, Acacia salicina, Cassia sturtii and Adenocorpus foliosus. Small Ruminant Research, volume 52, p. 13-18.

Yayneshet T, Eik L O and Moe S R 2009 Seasonal variations in the chemical composition and dry matter degradability of enclosure forages in the semi-arid region of Northern Ethiopia. Animal Feed Science and Technology 148: 12-33.

Received 10 December 2014; Accepted 19 January 2015; Published 3 March 2015

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