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Saltbush (Atriplex halimus)

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Datasheet

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) 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, they can be eaten cooked, like spinach or raw, like salad.

Morphology

Saltbush (Atriplex halimus) 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). Saltbush (Atriplex halimus) 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) (OEP, 2012; Tutin et al., 1993). 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). Saltbush 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 halimus. Suspecies halimus and subspecies schweinfurthii. Those subspecies have several differences in habit: 

  • halimus is shorter (1-2 m tall) than schweinfurthii (1-3 m tall in )).
  • halimus has erect and scorpoioides leafy twigs while those of schweinfurthii are rigid and reddish in colour;
  • leaf/stem ratio is higher for halimus (Le Houérou, 1992).

Among other differences it should be noted that these 2 subspecies do not grow in the same agroecological conditions: 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 (Atriplex halimus) is mainly used for forage and land reclamation. Leaves are edible and can be eaten raw like salad or cooked like spinach. It makes valuable wind-break in coastal areas and is sometimes grown in soil reclamation projects since it is able to accumulate ions of salinity Na+, and Cl- 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 

Saltbush (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, North Sea in Belgium and the UK, and 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 (Atriplex halimus) can be found from sea level up to an altitude of 900 m in coastal areas or in inland desert regions of the world. It can survive in places where temperatures do not go down -10°C. Below this temperature the plant can be damaged by frost but it is able to recover (Bean, 1981). Saltbush (Atriplex halimus) 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 (with pH that can range from 9 to 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, 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 places where rainfall can be as low as 200-400 mm, in rainfed conditions, saltbush (Atriplex halimus) could yield 2-10 tonnes DM/ha/year biomass or 2-4 tonnes DM/ha/year good quality forage (Ben Ahmed et al. 1996; Le Houérou, 1992). On soils having shallow limecrust, less demanding species like A. halimus subsp, schweinfurthii did better but their yield was, naturally, lower: 1-5 t DM/ha/year, of which about 50% is forage (Le Houérou, 1992).

Under irrigation, yields up to 30 tonnes DM/ha/year could be extrapoled from plots in the USA and Israel (Le Houérou, 1992).

Cultivation

Although saltbushes are found on saline soils in their native habitat, it is not a requisite for plantations; all 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 saltbush (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 spacing (500 plants/ha) to 1.5 x 4 m spacing (1500 plants/ha). There should be enough space between the rows so that livestock can move along the rows, but in a row, the plant should be closely spaced so that they make a hedge. Competing vegetation must be reduced to a minimum. Animals should not enter the sward before the seedlings are well established, neither should they 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, 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 ashes (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

Saltbush (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., 1993: Le Houérou, 1992). Saltbush is also 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
Potential constraints 

Minerals

Saltbush (Atriplex halimus) was 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 (36 to 144 g/kg DM) 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 sp. may contain high levels of micro-minerals like Co, Mo, 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). Also, saltbush (Atriplex halimus) must be grazed carefully when the plant is grown on contaminated soils (around abandoned mines).

Oxalates

Oxalic acid (oxalate) exists in saltbush  (Atriplex halimus) at various levels. Levels of 25 to 64 g/kg DM of oxalic acid were found in saltbush leaves, but should not be toxic (Ellern et al., 1974). At a level of 70-80 g/kg DM, oxalates can poison ruminants: such levels have been reported in various Atriplex species (Hungerford, 1990; Malcolm et al.,1988;  Davis, 1981 cited in El Shaer, 2010). Oxalates may be responsible for reducing calcium availability by creating insoluble calcium oxalate in the rumen and kidneys, creating kidney damages. Calcium cannot be available at the intestine level because of oxalic acids content in saltbush. In a 4-week experiment, 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

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

Ruminants 

Saltbush (Atriplex halimus) is mainly used by small ruminants and particularly sheep. Most of the results and experiments deal with this species.

Intake

Saltbush (Atriplex halimus) was reported  to have evident acceptability to livestock and to be fairly palatable during wet season and poorly during the dry season, in sheep and goats (El Shaer, 2010; Wills et al., 1990). However, when offered among several other shrub and legume tree species, goat and sheep ate saltbush (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 71.6 % 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 organic matter digestibility was the highest with 71% compared to 60 to 68% (Abbeddou et al., 2011).

When animals are not used to consume saltbush, an adaptation period of about 4 weeks is recommended (Valderrabano et al., 1996). The dry matter intake (DMI) of sheep and goat grazing saltbush as sole pasture increased to 72 - 78 g DM / kg BW0.75 and simultaneously, water intake was almost doubled in comparison with control diet (Otal et al., 2010; Valderrabano et al., 1996). 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 is low (36 to 48 g DM/kg BW0.75) when sodium chloride content is 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) replaces alfalfa hay, DMI decreases down to 40 g DM / kg BW0.75 with simultaneously, an increase of water intake from 7.4 to 10.6 l/day (Abu-Zanat et al., 2005). Such values (6.5 to 13 L/kg DM intake) are observed with sheep and goats fed with saltbush (Atriplex halimus) with high (93 – 146 g/kg DM) sodium chloride content (Alicata et al., 2002).

When saltbush from Canary islands is offered as sole diet to goat males in autumn, the DMI (17 g / kg BW0.75) and the DM digestibility (38%) are very low probably because its low CP content (7.5 g/kg DM) (Alvarez et al., (2008).

Saltbush (Atriplex halimus) can 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 (Atriplex halimus) is fed alone to rams, DM digestibility (DMD) varies (56 to 71 %) according to the season (Alicata et al., 2002). The organic matter digestibility in the rumen is potentially high with 76% as well as the crude protein digestibility with 92% (Abbeddou et al., 2011). That makes Atriplex halimus good forage either as sole forage or as supplement for stimulating the digestion of poor quality forages like straws.

Sheep

When saltbush (Atriplex halimus) and Salsola vermiculata were sown on natural rangeland in semi-arid region, it improved biomass production for several years and consequently increased animal performances (Osman et al., 2006). These authors observed that 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 growth of their lambs was also increased. In such a system, supplementation is reduced and total benefit increased (Osman et al., 2006).

The results in the table below showed that saltbush (Atriplex halimus) could partly or totally replace cereal straw as forage in diets supplemented with concentrates without decreasing animal performances.

It should be pointed out that because saltbush composition may vary in large extent (see above) according to the season, the leaves proportion, the location etc. results can also be variable.

Saltbush (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 part below).

Goat

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

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
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). This position is reinforced by the safe traditional use of this forage to feed sheep, cattle, and more particularly goats and camels (Kadi et al., 2016; Boussaid et al., 2004 for more information see Ruminants section). In addition, saltbush (Atriplex halimus) leaves are being used without problem for centuries in human nutrition, mainly as condiment, raw in salads or cooked in various preparations for example in North Africa countries or in France (Heitz, 2016; Khammar et al., 1997; Moldenke et al., 1952).

Saltbush (Atriplex halimus) leaves are a potential forage with a moderate calculated digestible energy content: 5.16 MJ/kg DM and a theoretically valuable protein content (15-20% DM), 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 the presence of a very high content of sodium (3 to 8% of DM depending on the Na content of the soil used to grow the plant). Maximum recommended content of Na in a rabbit’s complete diet is 0.6% DM (Gidenne et al., 2010) even if it is known that rabbit can grow and reproduce with higher sodium intake provided by some desert well waters (Ahmed et al., 2004).

That is why, before of any use of this forage in rabbit feeding, direct experiments are strongly recommended and the maximum level of incorporation in a complete diet would most probably not exceed 10-15%.

Nutritional tables
Tables of chemical composition and nutritional value 
References
References 
Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. https://www.feedipedia.org/node/24708 Last updated on February 8, 2019, 17:57

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