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Saltbush (Atriplex halimus)

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Description
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Common names 

Saltbush, Mediterranean saltbush, sea orache, shrubby orache [English]; arroche, arroche en arbre, arroche halime, arroche marine, épinard de mer, fessecul, pourpier de mer [French]; Strauchmelde [German]; Alimo, porcellana marina [Italian]; espique, salgadeira [Portuguese]; álimo, armuelle glauco, marisma, orzaga, osagra, ozagra, ozayra, sagra, salá, salada, salada blanca, salado, salado blanco, salao, salgada, salgado andaluz, sosa, sosera [Spanish]; Полухрастовидна лобода [Bulgarian]; מַלּוּחַ קִפֵּחַ [Hebrew]

Feed categories 
Description 

Saltbush (Atriplex halimus L.) is a halophytic perennial shrub that can grow in arid and semi-arid conditions. Its resistance to high levels of salinity and drought makes it a suitable species for landscaping in arid and salt-affected areas where it produces valuable forage for livestock (Walker et al., 2014b; Wills et al., 1990). Saltbush leaves are edible and they can be eaten cooked, like spinach or raw, like salad.

Morphology

Saltbush is a densely tufted halophytic shrub that grows to a height of 2-3 m and spreads to 2.4 m in width (OEP, 2012; Tutin et al., 1993). It is deeply rooted (Walker et al., 2014b). The leaves are silvery white in colour. The erected stems bear alternate leaves very variable in shape and dimensions (up to 4 cm in length). The inflorescence is born on leafless twigs, it is a more or less dense terminal panicle of small, yellowish or green flowers (OEP, 2012; Tutin et al., 1993). The fruits are numerous, horizontally spreading, coriaceous, kidney-shaped, 3.5-4 x 5-6 mm (Flora of Pakistan, 2018; OEP, 2012). The seeds are 1.5 mm, brown to dark brown (Flora of Pakistan, 2018).

There are 2 subspecies of Atriplex halimushalimus and schweinfurthii. Atriplex halimus subsp. halimus is is shorter (1-2 m) than Atriplex halimus subsp. schweinfurthii (1-3 m). It has a higher leaf/stem ratio and it has erect and scorpoioides leafy twigs while those of subsp. schweinfurthii are rigid and reddish in colour (Le Houérou, 1992). Subsp. halimus is commonly found in semi-arid and sub-humid Mediterranean zones, occasionally in the arid zone, Mediterranean, Atlantic and North Sea Shores while subsp. schweinfurthii is adapted to arid areas, gypsoferous marls and saline depressions, occasionally in desert depressions having a water table, often in abandoned cropland (Franclet et al., 1971).

Uses

Saltbush is mainly used for forage and land reclamation. Saltbush leaves are edible and can be eaten raw like salad or cooked like spinach in various preparations for example in North Africa countries or in France (Heitz, 2016; Khammar et al., 1997; Moldenke et al., 1952). It makes valuable wind-break in coastal areas and is sometimes grown in soil reclamation projects since it is able to accumulate Na+ and Cl- salinity ions and other anions in its tissues (PFAF, 2014; Nemat Alla et al., 2011; Ben Hassine et al., 2009; Martinez et al., 2005; Ben Ahmed et al., 1996).

Distribution 

Atriplex halimus originated from Europe and Northern Africa, including the Sahara in Morocco. It was already described in the Talmud (Moldenke et al., 1952). It is naturally found around the Mediterranean Basin from Southern Europe to North Africa and the Arabic Peninsula. Northwards, it can be found along the Atlantic Ocean in France, the North Sea in Belgium and the UK, and the Black Sea in Bulgaria (PFAF, 2014). Eastwards it has been reported in Iran and Pakistan. Depending on its subspecies (halimus or schweinfurthii), saltbush thrives on semi-arid and sub-humid areas or on arid areas (Le Houérou, 1992).

Saltbush can be found from sea level up to an altitude of 900 m in coastal areas or in inland desert regions. It can survive in places where temperatures do not go under -10°C. Below this temperature, the plant can be damaged by frost but it is able to recover (Bean, 1981). Saltbush does well on a wide range of soils that are well-drained and not too fertile with a fine to coarse structure. It grows well on saline or alkaline soils (pH  9-11) (Le Houérou, 1992; Thomas, 1992). It thrives on dry soils including pure sands and on soils contaminated by trace elements. Under cultivation, saltbush shows the best development and highest productivity on medium textured deep soils (Le Houérou, 1992). Saltbush is resistant to salted winds (Rosewarne EHS, 1984 cited by PFAF, 2014). Though it prefers full sunlight, saltbush can grow under semi-shade. Saltbush does not well under very wet conditions (Thomas, 1992 cited by PFAF, 2014).

Forage management 

Yield

In areas where rainfall was as low as 200-400 mm, in rainfed conditions, Atriplex halimus could yield 2-10 t DM/ha/year biomass or 2-4 t DM/ha/year of good quality forage (Ben Ahmed et al. 1996; Le Houérou, 1992). On soils having shallow limecrust, A. halimus subsp, schweinfurthii, a less demanding subspecies did better but the yield was lower: 1-5 t DM/ha/year, of which about 50% is forage (Le Houérou, 1992). Under irrigation, yields up to 30 t DM/ha/year could be extrapoled from plots in the USA and Israel (Le Houérou, 1992).

Cultivation

Although saltbush is found on saline soils in its native habitat, it is not a requisite for plantations; all Atriplex species grow on non saline soils as long as the soil reaction is alkaline (Le Houérou, 1992).

In New Zealand, it has been recommended to sow freshly collected dried seeds or to propagate Atriplex halimus from one-season-old wood cuttings grown in containers. The recommended spacing between cuttings for the establishment of a forage bank was reported to be from about 5 x 5 m (500 plants/ha) to 1.5 x 4 m (1500 plants/ha). There should be enough space between the rows for livestock to move along them, but plants should be closely spaced within a row to make a hedge. Competing vegetation must be reduced to a minimum. Animals should not enter the sward before the seedlings are well established, and they should no enter the sward during winter (Le Houérou, 1992; Wills et al., 1990). Saltbush can be grown in association with dryland pasture plants (e.g. sheep’s burnet Sanguisorba minor, birdfoot trefoil, chicory, prairie grass, wheatgrass) that can be broadcast or sown between the shrubs to increase the productivity of these forage banks and to provide soil cover (Wills et al., 1990).

In Northern Africa, high density plantations (3000 plants/ha) or planting as contour strip in cereal crop (with a spacing between rows that allow mechanical cultivation and harvesting in cereal crop) have been recommended.  Once saltbush is ready for grazing, it should be totally grazed or cut every year in late summer-early fall in order to prevent the plant to become woody and unpalatable even to camels (Le Houérou, 1992). A second period of browsing should be allowed during spring as saltbush can regrow and rejuvenate quite readily. Cuttings also allow rejuvenation of the shrub which maintains its high foliage/stem ratio (about 70-80%) during about 6 months and has much better forage quality with higher protein content and lower amount of salt and ash (Le Houérou, 1992). As for many shrubs, saltbush management results from trade-off between high yield and good survival rate (planting at high density does not allow the roots to become very deep and the plant may die during dry periods). (Le Houérou, 1992).

Environmental impact 

Erosion control, windbreak and soil improver

Atriplex halimus has a deep, strongly developed taproot that can go as deep as 10 m below ground surface. It can bind the soil and prevent erosion (Ortiz-Dorda et al., 2005; Abbad et al., 2004; Chisci et al., 1993Le Houérou, 1992). Saltbush is a pioneer species on sandy soils and a very good windbreak: it reduces wind speed at ground level and runoffs. These properties can be useful for dune stabilization and against desertification (PFAF, 2014; Nedjimi et al., 2013Wills et al., 1990). The important biomass provided by saltbush helps restoring soil fertility: it is adding organic matter that increases soil stability and improves permeability, hence rain-use efficiency but also soil microbial activity (Le Houérou, 1992).

Soil reclamation

Saltbush (Atriplex halimus) can draw salt out of the soil and has thus been used in soil-reclamation projects to de-salinate the soil in marginal and degraded soils (PFAF, 2014; Wills et al., 1990).

 

Nutritional aspects
Nutritional attributes 

Atriplex halimus contains moderate amounts of protein and fibre, but its composition is highly variable: protein content can vary from 6% DM to more than 25% DM depending on maturity, season, location and subspecies. Saltbush is extremely rich in minerals, with an ash content higher than 18% and sometimes higher than 35% DM. As noted in the Constraints section this high mineral content is accompanied by high contents in sodium and chlorine.

Potential constraints 

Minerals

Atriplex halimus has been reported to contain high levels of chlorine, sodium and other minerals (El Shaer, 2010; Le Houérou, 1992). For example, a wide range of chlorine and sodium was observed in Israel (3.6 to 14.4% DM for chlorine and 5.4 to 11.1% for sodium) according to the location (Ellern et al., 1974). Consequently it is recommended to provide freely available fresh water with low mineral content in order to prevent DM intake reduction due to high mineral content.

Because Atriplex species may contain high levels of minerals such as Co, Mo or Se that can interfere with other minerals, the mineral status of the animals, especially producing animals, must be controlled and diets adapted accordingly (Alazzeh et al., 2009; Alazzeh et al., 2004). Atriplex halimus must be grazed carefully when the plant is grown on contaminated soils (around abandoned mines).

Oxalates

Oxalic acid (oxalate) is present in Atriplex species, and levels up to 70-80 g/kg DM, that are toxic to ruminants, have been reported (Hungerford, 1990; Malcolm et al., 1988; Davis, 1981 cited in El Shaer, 2010). Lower levels ranging from 25 to 64 g/kg DM have been found in Atriplex halimus leaves (Ellern et al., 1974). Oxalates reduce calcium availability by creating insoluble calcium oxalate in the rumen and kidneys, creating kidney damages, and reduces calcium availability in the intestine. In a 4-week experiment in Jordan, lower calcium level was observed in blood serum when Atriplex halimus was mixed in equal parts with Atriplex nummularia and offered at 0.4 kg DM/d to dairy Awassi ewes plus concentrates compared to control group fed with straw (Alazzeh et al., 2004). The same phenomenon was observed for lambs at a lower level (Alazzeh et al., 2009).

Tannins

Atriplex halimus may contain high levels of condensed tannins (12 to 15 g/kg DM) as observed in Jordan (Abu-Zanat et al., 2003).

Ruminants 

Atriplex halimus is mainly used to feed small ruminants and particularly sheep (Kadi et al., 2016; Boussaid et al., 2004). As shown below, it can partly or totally replace cereal straw as forage in diets supplemented with concentrates without decreasing animal performance. However, because its composition may vary widely depending on the season, leaf:stem ratio, location etc. results can also be variable. Atriplex halimus can be used as forage source for maintenance, but must be supplemented with energy when growth or milk production is expected. Also, due to its high sodium content, clear water must be freely available. Finally, because high oxalic acid content may occurs, mineral supplementation must be adapted in order to limit calcium deficiency (see Caution).

Intake

Atriplex halimus has been reported to be well accepted by livestock: fairly palatable for sheep and goats during the wet season but poorly palatable during the dry season (El Shaer, 2010; Wills et al., 1990). However, in a cafeteria trial with goats and sheep comparing 3 Atriplex species and 3 legume trees (Acacia and Cassia), Atriplex species were the less preferred species: particularly, animals ate Atriplex halimus at less than 5% of the total intake within 15 min (Degen et al., 2010). When compared to straws, hays or olive leaves incorporated into a total diet at 72 % and offered to sheep (42 kg BW), the dry matter intake (DMI) was lower (0.83 vs 1 to 1.1 kg DM) for saltbush than for all other forages, but the OM digestibility was the highest with 71% compared to 60 to 68% (Abbeddou et al., 2011b).

When animals are not used to consume saltbush, an adaptation period of about 4 weeks is recommended (Valderrabano et al., 1996). DMI of sheep and goats grazing saltbush as sole pasture increased to 72-78 g DM / kg BW0.75. Simultaneously, water intake almost doubled in comparison with control diet. Goats selected twigs with higher diameter (4.6 mm) than sheep (2.7 mm)(Otal et al., 2010; Valderrabano et al., 1996).

When fed alone to rams or lambs, the DMI of saltbush was low (36 to 48 g DM/kg BW0.75) when sodium chloride content was high: 146 vs 93 g/kg DM and 63.1 g/kg DM (Abu-Zanat, 2005; Alicata et al., 2002). When saltbush with high sodium chloride content (63.1 g/kg DM) replaced alfalfa hay, DMI decreased down to 40 g DM / kg BW0.75 while water intake increased from 7.4 to 10.6 l/day (Abu-Zanat et al., 2005). Such values (6.5 to 13 L/kg DM intake) were observed with sheep and goats fed with Atriplex halimus with high (93 – 146 g/kg DM) sodium chloride content (Alicata et al., 2002).

When saltbush from Canary islands was offered as sole diet to male goats in Autumn, the DMI (17 g / kg BW0.75) and the DM digestibility (38%) were very low probably because the low protein content (7.5 g/kg DM) (Alvarez et al., 2008).

Saltbush could be ensiled with molasses and fed to ram supplemented with 300g/d barley grain without any problem and the DMI is about 33 g DM/kg BW0.75 (Alsersy et al., 2015) Adding commercial cellulolytic enzymes into the silage, increased the DMI up to 64 g DM/kg BW0.75 (Alsersy et al., 2015.)

Digestibility

When saltbush was fed alone to rams, DM digestibility varied from 56 to 71% depending on the season (Alicata et al., 2002). The OM digestibility in the rumen is potentially high with 76% as well as the crude protein digestibility with 92% (Abbeddou et al., 2011b). This makes Atriplex halimus good forage either as sole forage or as supplement for stimulating the digestion of poor quality forages like straws.

Sheep

Atriplex halimus and Salsola vermiculata sown on natural rangeland in a semi-arid area in Syria improved biomass production for several years, which in turn increased animal performance. Over seven consecutive seasons, whatever the stocking rate (from one sheep per 2.25 ha/year up to 1 for 0.75 ha/year), milk yield and ewe body weight of Awassi ewes increased compared to ewes on natural rangeland, and lamb growth also increased. In such a system, supplementation was reduced and profit increased (Osman et al., 2006).

Country Breed / Physiological stage Experiment Level of Saltbush Main results Reference
Italy Comisana lambs (33 kg) Lambs grazed for 51 days, Atriplex supplemented or not with barley straw ad libitum and 200 g/d of barley grain Grazing ad libitum Without supplement, lambs lost weight (- 60g/d) and with supplement gain about 60 g/d Stringi et al., 2009
Jordan Awassi lactating ewes (58 kg) Atriplex sp. replacing barley straw plus 4,5 kg concentrate 50 or 100 % Atriplex can totally replace barley straw and gives the same results for milk production or lamb growth rate Abu-Zanat et al., 2006
Jordan Awassi lambs (23 kg) Atriplex sp. replacing barley straw plus 1.1 kg concentrate 0,2 kg DM Total DMI is lower with Atriplex than with straw (0,96 vs 1,12 kg DM/d) but daily weight gain is not different (193 vs. 205 g/d) Alazzeh et al., 2009
Jordan Awassi lactating ewes (55kg) early lactation Atriplex sp replacing barley straw plus 1,5 to 0,9 kg concentrate according to lactation stage 0,2 kg DM/d/ewe Atriplex sp. can totally replace straw and gives the same results as milk production or lamb growth rate Alazzeh et al., 2004
Jordan Awassi lambs (15 kg) Atriplex dried, grinded and incorporated into a total diet replacing 25 or 50% of wheat straw 7 or 15 % DM No difference in DMI, water intake, daily weight gain or carcass quality Obeidat et al., 2016

Goats

Saltbush supplemented with barley could be used for kid fattening without adverse effects on their growth and meat characteristic (El Shaer, 2010).

Rabbits 

No information on the direct use of saltbush (Atriplex halimus) in feeding of domestic rabbit seems available in the international literature (as of 2018). However, according to in vitro studies with rabbit caecal content, saltbush seems to be a suitable forage for rabbits (El-Adawy et al., 2008). As noted in the previous sections, saltbush is used safely for both human food and ruminant feeding.

Saltbush leaves are a potential forage with a moderate calculated digestible energy content: 7.0 MJ/kg DM and a theoretically valuable protein content but with a very low digestibility coefficient according to the chemical composition of the forage (Lebas, 2016). The utilisation of this halophyte forage in rabbit nutrition is most probably limited by a very high sodium content. The maximum recommended content of Na in a rabbit’s complete diet is 0.6% DM (Gidenne et al., 2010) even if it has been shown that rabbits can grow and reproduce with the higher sodium intake provided by well waters in certain desertic areas (Ahmed et al., 2004).

For those reasons, direct experiments are strongly recommended before using this forage in rabbit feeding. In any case, the maximum inclusion rate in a complete diet would most probably not exceed 10-15%.

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 38.1 10.8 24.4 58.4 10  
Crude protein % DM 16.7 4.7 6.3 25.5 51  
Crude fibre % DM 16.7 8.8 7.6 32.4 11 *
Ether extract % DM 2.2 0.5 1.4 3.2 15  
Ash % DM 27 4.7 18.4 36.7 50  
Insoluble ash % DM 0.5 0.5 0.2 1.5 7  
Neutral detergent fibre % DM 38.8 10.6 25.3 64.6 23 *
Acid detergent fibre % DM 21.6 7.7 9.7 40.2 42 *
Lignin % DM 8.8 2.6 4.7 14.5 19 *
Gross energy MJ/kg DM 14.6       1 *
               
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 19.9 6.3 8 28.5 32  
Phosphorus g/kg DM 2 0.7 0.9 3.2 32  
Magnesium g/kg DM 14.8 3.2 9 19.8 29  
Potassium g/kg DM 52.6 13.8 18.2 80.2 29  
Sodium g/kg DM 46.75   29 66 4  
Chlorine g/kg DM 55.3   17 94 4  
Sulfur g/kg DM 4.8   4 5 4  
Manganese mg/kg DM 70 32 24 106 5  
Zinc mg/kg DM 30   13 50 4  
Copper mg/kg DM 17 5 12 23 5  
Iron mg/kg DM 387 142 148 723 28  
               
Secondary metabolites Unit Avg SD Min Max Nb  
Tannins (eq. tannic acid) g/kg DM 6   5 8 3  
Tanins, condensed (eq. catechin) g/kg DM 20 20 2 70 9  
Oxalates g/kg DM 55.8 25.7 26.6 107 11  
               
In vitro digestibility and solubility Unit Avg SD Min Max Nb  
In vitro DM digestibility (pepsin) % 74 9 57 80 6  
               
Ruminant nutritive values Unit Avg SD Min Max Nb  
DE ruminants MJ/kg DM 8         *
ME ruminants MJ/kg DM 6.4         *
Energy digestibility, ruminants % 55         *
OM digestibility, ruminants % 57.5   52.9 66.3 4  
Nitrogen digestibility, ruminants % 64.7   34 77.6 4  
Nitrogen degradability (effective, k=6%) % 66       1 *
a (N) % 27       1  
b (N) % 57       1  
c (N) h-1 0.129       1  
Dry matter degradability (effective, k=6%) % 58       1 *
a (DM) % 23       1  
b (DM) % 57       1  
c (DM) h-1 0.097   0.095 0.099 2  
               
Rabbit nutritive values Unit Avg SD Min Max Nb  
DE rabbit MJ/kg DM 7         *
MEn rabbit MJ/kg DM 6         *
Energy digestibility, rabbit % 47.8         *
Nitrogen digestibility, rabbit % 121         *

The asterisk * indicates that the average value was obtained by an equation.

References

Abbad et al., 2004; Abu-Zanat et al., 2003; Alibes et al., 1990; Alicata et al., 2002; Alvarez et al., 2008; Bouazza et al., 2012; Boufennara et al., 2012; Davis, 1981; Degen et al., 2010; El Shaer, 2010; El-Adawy et al., 2008; Haddi et al., 2003; Kaitho et al., 1997; Kaitho et al., 1998; Pozy et al., 1996; Salem et al., 2012; Stringi et al., 2009; Tisserand, 1985; van Niekerk et al., 2004; Watson, 1990; Wills et al., 1990; Yaakoub, 2006

Last updated on 08/07/2019 10:12:18

References
References 
Datasheet citation 

Heuzé V., Tran G., Hassoun P., Lebas F., 2019. Saltbush (Atriplex halimus). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/24708 Last updated on July 8, 2019, 10:44

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