Argan Research Articles

Ingestive behavior of goats grazing in the Southwestern Argan ( Argania spinosa) forest of Morocco

This study, conducted in the southwestern Argan forest of Morocco, aimed to assess goat feeding behaviour and goat diet composition. Overall grazing time averaged 387 min/day and represented on average 70% of total time when the goats were released on pasture. Grazing time was higher during winter months. Bipedal grazing was low and never exceeded 10%. Soil grazing varied according to the period of the year. Aerial grazing increased when herbaceous layer was depleted. Walking activity that accounted for 24% of the presence of goats on pasture, varied with the period of the year. Resting time accounted for less than 39 min contributing less than 6% of the temporal behavior budget. The contribution of all argan to the goat's diet ranged from a minimum of 47% in June to a maximum of 84% in December. Aerial argan leaves contributed continuously to goat diets a proportion from 35% to 68%. Under-tree grazing accounted for 50% during June when herbaceous plants and stubble were available, but less than 15% when they were depleted. Total intake changed with advance in season. Total goat intake reached its lowest level when animals spent large amounts of their time grazing argan trees in response to shortage of feed on the ground. Variation of the intake rate was mainly due to bite size, since rate of biting varied little among months. Goats ingested larger bite size from March through June when argan fruits were available and when diversity of availability was the highest. The goats adaptation capacity in argan forest allows a kid meat production when other ruminants such as sheep probably would not be able to do.

Influence of Roasting and Seed Collection on Argan Oil Odorant Composition

Argan tree (Argania spinosa (L.) Skeels) is endemic in Morocco. The aroma compounds of argan oil prepared from roasted and unroasted argan kernels were analyzed using GC-MS and olfactometry. Influence of the fruit peeling method on the olfactometric parameters was also studied. Oil coming from unroasted kernels furnished fourteen compounds if the fruits had been mechanically-peeled fruits (uRK), and twenty two when the kernels had been goat digested (GuRK). Thirteen compounds were common to the two studies. The oil obtained from roasted kernels of mechanically-peeled fruits (RK) furnished nineteen compounds. Twenty one were isolated from the oil obtained from roasted kernels of goat digested fruits (GRK). Twelve compounds were common to the two analyses. In all oil samples, the aldehyde/ketone derivatives composed the largest group of odorants. Acetophenone and p-methylacetophenone appear to be the most important contributors to the RK oil aroma. The unpleasant smell presented by argan oil prepared from naturally-peeled argan fruits (GuRK, GRK) could result from the presence of one or two odorants presenting a rancid odor.

Novel Production of Isochainin by a Strain of Streptomyces sp. Isolated from Rhizosphere Soil of the Indigenous Moroccan Plant Argania Spinosa L

An actinomycete strain (designated Ap1) isolated from the rhizosphere soil of Argania spinosa L. strongly inhibited the growth of two plant pathogens: Fusarium oxysporum f.sp. albedinis and Verticillium dahliae. The spore morphology suggested that the Ap1 strain belonged to the genus Streptomyces. The antifungal compound produced by Ap1 was purified by HPLC and identified as the polyene macrolide, isochainin, by NMR and mass spectroscopy. Ap1 showed normal biosynthesis of isochainin in comparison with S. cellulosae ATTC 12625, in which precursor-directed biosynthesis by feeding ethyl (Z)-16-phenylhexadec-9-enoate to the culture medium is required. In addition, Streptomyces sp. strain Ap1 produces isochainin with a 6.5-fold higher concentration than Streptomyces cellulosae ATTC 12625.

Estimating allelic richness and its diversity

Assessing allelic richness in a set of populations requires that variations of sample size be taken into account. One way of doing this is to estimate the number of alleles expected in samples of specified size, using the rarefaction method applied in ecology. An alternative method, based on extrapolation, consists of adding to the number of alleles actually seen in a population the expected number of alleles missing, given the number of genes examined in the population and the allelic frequencies observed over the whole set of populations. Heterogeneity of allelic richness across populations and across loci can also be tested in this framework by numerical re-sampling. Both methods provide a measure of “private” allelic richness, a useful criterion in genetic diversity preservation, by allowing evaluation of the uniqueness of each population in terms of allele numbers. The two methods are compared on isozyme loci in the argan tree of Morocco and on microsatellite genotypes in the European pig. In both species, allelic richness and gene diversity behave quasi-independently over the populations compared and a higher differentiation is observed in allelic richness compared to gene diversity. In general, the rarefaction technique is sensitive to the sample size of reference and may lack sensitivity to rare alleles when the sample size of reference is small. Extrapolation may thus be recommended especially when the sample sizes of the populations are either low on average or highly unbalanced among populations.

Tocopherols and Saponins Derived from Argania spinosa Exert, an Antiproliferative Effect on Human Prostate Cancer

The aim of our study is to evaluate the antiproliferative effect of tocopherols obtained from alimentary virgin argan oil extracted from the endemic argan tree of Morocco and of saponins extracted from argan press cake on three human prostatic cell lines (DU145, LNCaP, and PC3). The results were compared to 2-methoxyestradiol as antiproliferative drug candidates. Cytotoxicity and antiproliferative effects were investigated after cells' treatment with tocopherols and saponins compared to 2-Methoxyoestradiol as the positive control. Tocopherols and saponins extracted from argan tree and 2-methoxyestradiol exhibit a dose-response cytotoxic effect and an antiproliferative action on the tested cell lines. The best antiproliferative effect of tocopherols is obtained with DU145 and LNCaP cell lines (28 μg/ml and 32 μg/ml, respectively, as GI50). The saponins fraction displayed the best antiproliferative effect on the PC3 cell line with 18 μg/ml as GI50. Our results confirm the antiproliferative effect of 2-methoxyestradiol and show for the first time the antiproliferative effect of tocopherols and saponins extracted from the argan tree on hormone-dependent and hormone-independent prostate cancer cell lines. These data suggest that argan oil is of potential interest in developing new strategies for prostate cancer prevention.

We-P13:325 Metabolyc syndrome in HD patients: Insulin resistance, visceral adiposity, inflammation and iron

The characteristics of meat from goats raised in the Argan tree forest in the south-western part of Morocco were studied in two experiments. Each experiment was carried out on three groups of six male goats. They were reared either indoors (IC) and fed concentrate or outdoors where they grazed in the Argan tree forest and were offered concentrate (OC) or only Argan fruit pulp (OS). Outdoor-raised goats had a very low growth rate in the first experiment (34 g/d), whereas it was relatively high in the second experiment (64 g/d) in which herbaceous vegetation availability was higher. In each experiment, omental (OM) and perirenal (PR) weights were the lowest in the two groups of goats raised outdoors. Lipid and cholesterol contents in muscles were lower in goats raised in the Argan tree forest than in those raised indoors. Outdoor-raised goats had particularly high proportions of odd-chain fatty acids (FA), branched-chain (FA) of the iso and anteiso series in adipose tissues and muscles and higher n − 6 and n − 3 polyunsaturated FA (PUFA) proportions and a lower n − 6:n − 3 PUFA ratio than indoor-raised goats. Indoor-raised goats had a higher proportion of palmitic acid and a lower proportion of archidic acid than outdoor-raised goats. In indoor-raised goats, the proportions of Δ9 straight-chain mono-unsaturated fatty acids (MUFA) (C16:1n − 7 and cis C18:1n − 9) were relatively higher than those of total MUFA, because of lower percentages of some MUFA, such as C16:1n − 9 and other isomers of oleic acid. The low fat content and FA profile of the meat from the goats reared in the Argan tree forest conveyed beneficial characteristics to this meat in regards to human health. The relatively high contents of branched-chain FA of iso and anteiso series and PUFA in the meat from goats raised in the Argan tree forest could be considered as a sign of typicity.

Variability of leaf stomatal density of adult trees of Argania spinosa (L.) Skeels in the field

Stomatal density is recorded on both faces of the two types of argan (Argania spinosa (L.) Skeels) leaves (simple and grouped) of 30 adult trees within three populations at Ait Melloul, Ait Baha and Argana, three sites in the south-west of Morocco, during three consecutive years, 1994–97. No stomata are observed at adaxial leaf surface characterizing argan as a hypostomatous species. Stomata density varies from 312 to 50 stomata per mm2 for simple leaves and from 294 to 62 stomata per mm2 for grouped leaves setting a large variability interval within argan populations. Tree genotype and its interaction with year are the sole significant sources of variation for simple or grouped leaves. Interpopulation (population) contribution to total variance is lower than intra-population (tree/population or its interaction with year). Repeatability (an estimate of broad sense heritability) values, 26.7% −38.3% for simple leaves and 18.1 to 46.1 for grouped leaves are relatively high within each population for this ecophysiological character.

Effect of feeding on fatty acid composition of muscles and adipose tissues in young goats raised in the Argan tree forest of Morocco

The characteristics of meat from goats raised in the Argan tree forest in the south-western part of Morocco were studied in two experiments. Each experiment was carried out on three groups of six male goats. They were reared either indoors (IC) and fed concentrate or outdoors where they grazed in the Argan tree forest and were offered concentrate (OC) or only Argan fruit pulp (OS). Outdoor-raised goats had a very low growth rate in the first experiment (34 g/d), whereas it was relatively high in the second experiment (64 g/d) in which herbaceous vegetation availability was higher. In each experiment, omental (OM) and perirenal (PR) weights were the lowest in the two groups of goats raised outdoors. Lipid and cholesterol contents in muscles were lower in goats raised in the Argan tree forest than in those raised indoors. Outdoor-raised goats had particularly high proportions of odd-chain fatty acids (FA), branched-chain (FA) of the iso and anteiso series in adipose tissues and muscles and higher n − 6 and n − 3 polyunsaturated FA (PUFA) proportions and a lower n − 6: n − 3 PUFA ratio than indoor-raised goats. Indoor-raised goats had a higher proportion of palmitic acid and a lower proportion of archidic acid than outdoor-raised goats. In indoor-raised goats, the proportions of Δ9 straight-chain mono-unsaturated fatty acids (MUFA) (C 16:1 n − 7 and cis C 18:1 n − 9 ) were relatively higher than those of total MUFA, because of lower percentages of some MUFA, such as C 16:1 n − 9 and other isomers of oleic acid. The low fat content and FA profile of the meat from the goats reared in the Argan tree forest conveyed beneficial characteristics to this meat in regards to human health. The relatively high contents of branched-chain FA of iso and anteiso series and PUFA in the meat from goats raised in the Argan tree forest could be considered as a sign of typicity.

Evidence of hypolipemiant and antioxidant properties of argan oil derived from the argan tree ( Argania spinosa)

Background: Virgin argan oil is of interest in cardiovascular risk prevention due to its fat composition and antioxidant compounds. Aims: We investigated with Moroccan subjects the effect of regular virgin argan oil consumption on lipid profile and antioxidant status and the in vitro effect of argan oil minor compounds (tocopherols, sterols and polyphenols) on LDL peroxidation. Design: Healthy subjects (20 men, 76 women) were studied. Sixty-two were regular consumers of argan oil and 34 were non-consumers. Methods: Fasting plasma lipids, antioxidant vitamins and LDL oxidation susceptibility were analyzed. In vitro LDL oxidation by phenolic and apolar compounds of virgin argan oil were performed. Results: Diet composition of argan oil consumers has a higher significant content of polyunsaturated fatty acids than that of non-consumers (8.8±1.0 vs. 6.6±0.9 g, P<0.05). Subjects consuming argan oil have lower levels of plasma LDL cholesterol (12.7%, P<0.05) and Lp(a) (25.3%, P<0.05) compared with the non-consumers. In argan oil consumers, plasma lipoperoxides were lower (58.3%, P<0.01) and molar ratio α-tocopherol/total cholesterol (21.6%, P<0.05) and α-tocopherol concentration (13.4%, P<0.05) were higher compared with the non-consumers group. In spite of higher levels of plasma antioxidant and lower levels of lipoperoxides in argan oil consumers, LDL oxidation susceptibility remained fairly similar. A strong positive correlation was observed between increasing phenolic extract, sterol and tocopherol concentrations and the LDL-Lag phase ( P<0.05). Conclusions: Our findings suggest for the first time that regular consumption of virgin argan oil induces a lowering of LDL cholesterol and has antioxidant properties. This oil offers an additional natural food to reducing cardiovascular risk.

Argan (Argania spinosa(L.) Skeels) seed germination under nursery conditions: Effect of cold storage, gibberellic acid and mother-tree genotype

Cette etude porte sur les effets de quatre durees de conservation des semences au froid, avec ou sans traitement a l'acide gibberellique (GA), sur la germination des noyaux de dix pied-meres d'arganier (Argania spinosa) en vue d'etablir un protocole simple de germination adaptable a des situations diverses. Le debut de la germination des semences d'arganier non traitees par GA et conservees a la temperature ambiante est retarde de trois jours par comparaison avec les semences stockees au froid ou traitees par GA. La germination est faible (35,5 %) et la contamination des semences ainsi que la fonte de semis en pre-emergence sont importantes. Par contraste, l'application de GA ou le stockage au froid a 4 °C pendant un minimum de un mois permet une augmentation significative de la germination qui atteint 60 %. La germination moyenne augmente remarquablement quand les deux traitements sont combines (79,5 %), ceci etant surtout du au fait que l'application de GA apres stockage au froid reduit les pertes dues a la contamination par les champignons et a la fonte de semis en pre-emergence. Dans ces conditions, et quand les semences ont ete stockees au froid pendant trois mois, le pourcentage final de germination a pu atteindre 95,0 % en fonction du pied-mere.

In vitro pollen germination of Argan (Argania spinosa (L.) Skeels)

An easy and reproducible pollen germination method for Argan (Argania spinosa (L.) Skeels) has been established using a combination of three phenological phases (flower bud BF, flower bud with an emerging style BFS and blooming flower FE), two germination media, two incubation temperatures (25°C and 30°C) and 14 genotypes. The number of germinated pollen and the pollen tube growth were observed. Best results were obtained with pollen extracted from FE on a solid 1% agar medium containing 20% sucrose, 200 ppm CaCI2 and 75 ppm H3BO3, at 30°C for a minimum of 20 h, while sustainable tube growth was maintained until the end of the experience. The pollen from BF phase does not germinate at all. The germination of the pollen from BFS, although low, was dependent on the genotype. Thus, emasculation is requested at early BF stages to avoid self-pollination prior to hand pollination. Highly significant differences between tree genotypes was observed for the number of germinated pollen and for tube growth showing a differential male-gametophytes potential fitness that could influence gene flow between trees.

Effect of light on germination of Argan (Argania spinosa (L.) Skeels) seeds

The effect of light was investigated in the aim to improve germination, which is a limiting factor for Argan (Argania spinosa (L.) Skeels) nursery plant production. Seeds from six different mother-trees were cold stored (4 °C), scarified before to be soaked in gibberellic acid (GA3) solution. Seeds were germinated at a 16/8 hours thermoperiod of 25/16 °C. Two light treatments were compared: daylight (14 hours photoperiod) and complete darkness. We assessed germination percentage, time to germination and germination period. In darkness the beginning of germination is delayed, the germination rate lowered as the final germination percentage (69.4% for light and 44.7% for darkness). Although there were significant differences between mother-trees, no interactions were observed between mother-tree and light treatment except for interval of germination, seeds of all mother-trees showing increased germination percentages under light conditions as compared to darkness.

Bayesian analysis of genetic differentiation between populations.

We introduce a Bayesian method for estimating hidden population substructure using multilocus molecular markers and geographical information provided by the sampling design. The joint posterior distribution of the substructure and allele frequencies of the respective populations is available in an analytical form when the number of populations is small, whereas an approximation based on a Markov chain Monte Carlo simulation approach can be obtained for a moderate or large number of populations. Using the joint posterior distribution, posteriors can also be derived for any evolutionary population parameters, such as the traditional fixation indices. A major advantage compared to most earlier methods is that the number of populations is treated here as an unknown parameter. What is traditionally considered as two genetically distinct populations, either recently founded or connected by considerable gene flow, is here considered as one panmictic population with a certain probability based on marker data and prior information. Analyses of previously published data on the Moroccan argan tree (Argania spinosa) and of simulated data sets suggest that our method is capable of estimating a population substructure, while not artificially enforcing a substructure when it does not exist. The software (BAPS) used for the computations is freely available from http://www.rni.helsinki.fi/~mjs.

Secondary metabolites from Argania spinosa (L.) Skeels

Argania spinosa (L.) Skeels is a tree that plays a crucial role in the rural and urban economy of Morocco. Not only is the tree used in traditional medicine but its fruits contain almonds used to prepare an edible oil, its leaves are utilized to feed cattle, and its wood is used as fuel. In addition the tree is particularly well-adapted to arid lands and could hence be used to limit the desert progression that is threatening subtropical African countries. Consequently a program aimed at a better understanding of all the aspects and uses of the argan tree is currently being carried out in Morocco. This review summarizes the results gathered so far on the phytochemical and pharmacological activity of A. spinosa.

The argan tree ( Argania spinosa ) in Morocco: Propagation by seeds, cuttings and in-vitro techniques

In South-western Morocco, the argan tree (Argania spinosa) is basis of a traditional agroforestry system. However, this system is no longer at equilibrium and there is an urgent need to renovate it. The natural reproduction of the tree has become difficult, and most attempts of artificial regeneration have failed. We have assessed three different propagation methods: seedlings, cuttings, and in-vitro micro-propagation. Our experiments, involving several seed collections, showed that germination occurred easily when using young ( 3 g). Nuts with thin walls germinated better than nuts with thicker walls. Sterilization prevented microbial contamination and improved germination. Vegetative propagation of the argan tree by cuttings was tried using lignified cuttings collected from adult trees or young stems from managed stockplants (three years old). Rooting rate seems to be dependent on genotype, and the best results were obtained from young stems sterilized to avoid fungal contamination. The success of in-vitro micro-propagation is also highly genotype-dependant. We developed a modified medium enabling up to 80–95% rooting rate for some clones. However, other clones were still recalcitrant. Whatever the propagation method used, special attention must be paid to the architecture and growth of the root system.

Argania spinosa (L.) Skeels flowering phenology

Argan (Argania spinosa (L.)Skeels) flowering was observed at Ait Melloul, Ait Baha andArgana, three sites in the south-west of Morocco during twoseasons, 1994–95 and 1995–96. Glomerule count wasmonitored on first-year and on last-year growth shootevery twenty days. Season was the primary source of variation ofglomerule count on argan first-year and last-yeargrowth shoots. The first season was very dry when flowering beganlate April, while the second was very humid and flowering startedearly December. In both cases flowering precocity was associated toprecipitation precocity, i.e. flowering would commence whenapproximately 100 mm rain was accumulated. High positivecorrelation between glomerule count and precipitation were observed.But, considering the two seasons, glomerule count always attained itspopulation maximum in spring even if differences were observedbetween sites. However, intensity and duration of the peak were alsodistinct depending on shoot type: on first-year growth shoot,glomerules were abundant but would last for a short period, whereason last–year growth shoot, they were less frequent but wouldlast for a longer period. Not all trees flowered during a season,although some trees flowered every season, showing the extremes ofthe large variability observed for glomerule count abundance andduration within argan populations.

Germination and seedling survival of Argan (Argania spinosa) under experimental saline conditions

Solutions of NaCl at various concentrations (0, 2·5, 5, 7·5 and 10 gl−1) were used to treat argan (Argania spinosa (L.) Skeels) at germination and as container-grown seedlings. We assessed germination percentage, radicle length and dry weight as well as seedling survival and number of days before seedling collapse. Increasing salt concentration did not delay the beginning of germination but it lowered the germination rate and reduced the final germination percentage. At the seedling stage, increasing salinity levels resulted in decreasing growth, increasing ionic toxicity symptoms and reduced survival as compared to the control. Argan did not behave as a salt-tolerant species showing damage at as low as 2·5 gl−1, the upper limit for survival being 7·5 gl−1. However the effect mother-tree was highly significant indicating that much selective potential is probably available for breeding for salt tolerance within natural argan populations.

Polyphenol investigation of Argania spinosa (Sapotaceae) endemic tree from Morocco

The leaves of Argania spinosa from Morocco were investigated for flavonoids and condensed tannins. Four flavonol glycosides were identified by 1H NMR as myricitrin, quercitrin, hyperoside and myricetin 3-O-galactoside. UV spectrophotometric and histochemical methods were carried out to quantify and locate flavonoids and condensed tannins from leaves, stems and thorns of A. spinosa. Both high content and cell localisation of total polyphenols could explain the Argan tree adaptation to aridity.

Argan (Sapotaceae) Trees as Reservoirs for Mediterranean Fruit Fly (Diptera: Tephritidae) in Morocco

Argan, Argania spinosa L. (Sapotaceae), forests cover a700,000 ha in the Souss region of Morocco and are known as an enormous potential reservoir of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) for nearby citrus orchards. We studied C. capitata population dynamics in a cattle- and insecticide-free domain from 1987 to 1990. Autumnal argan fruiting in 1986 and 1989 highly modified population dynamics by increasing the number of generations breeding in argan. Thus, up to 4 generations can breed in argan, whereas only 2 develop in spring fruiting alone. Most argans contained only a single oviposition. Oviposition was observed with autumnal fruiting from December to late June, just before the last fruit fell. Larval development began in argans still on trees and continued on fallen fruit. Numbers of eggs, larvae per fruit, and adult males captured per Procida trap increased from late May to June or July. Heterogeneity of argan tree phenology permits huge C. capitata populations with a large spread in adult emergences. Each argan produced on average 3 ± 1.3 adult flies. The proportion of aborted ovipositions was high, as was pupal mortality. Only 1 species of endoparasite, Opius concolor Szepligetti, emerged from argans. Parasitism remains constant from March to July but was too low to curb the enormous fly population increase.

Identifying Populations for Conservation on the Basis of Genetic Markers

To select candidate populations of wild species to be given priority for conservation, genetic criteria gained from the study of molecular markers may be useful. Traditionally, diversity measures such as expected heterozygosity or percentage of polymorphic loci have been considered. For conservation we propose instead that priority should be given to measures of allelic richness. To standardize the results of allelic richness across populations, we used the technique of rarefaction. This technique allows evaluation of the expected number of different alleles among equal‐sized samples drawn from several different populations. We also show how the contribution of each population to total diversity can be partitioned into two components. The first is related to the level of diversity of the population and the second to its divergence from the other populations. For conservation purposes the uniqueness of a population—in terms of its allelic composition—may be at least as important as its diversity level. These new descriptors are illustrated by means of isozyme and chloroplast DNA data obtained for an endangered tree species, the argan tree of Morocco (Argania spinosa(L.) Skeels). With these analyses the conservation value of the argan tree populations, especially those of two isolates present in the north of the country, can be better appreciated. The methods proposed to identify priority areas for conservation of the genetic resources of the argan tree are compared to those sometimes advocated in the case of reserve design, where one of the goals is to maximize species richness. Identificacón de Poblaciones para su Conservación en Base a Marcadores Genéticos Los criterios genéticos obtenidos del estudio de marcadores moleculares podrían ser útiles para seleccionar poblaciones de vida silvestre como candidatos con prioridad para su conservación. Tradicionalmente se consideran medidas de la diversidad como son la heterocigocidad esperada, o el porcentaje de loci polimórficos. Para medidas de conservación, nosotros proponemos en su lugar que la prioridad se enfoque en medidas de riqueza alélica. Para estandarizar los resultados de riqueza alélica entre problaciones, utilizamos una técnica de vacuidad. Esta técnica permite evaluar el número esperado de alelos entre muestras de igual tamaño obtenidas de diferentes poblaciones. Mostramos como la contribución de cada población a la diversidad total puede ser repartida en dos componentes; el primero esta relacionado con el nivel de diversidad de la población y el segundo con su divergencia de las otras poblaciones. Para propósitos de conservación, la singularidad de una población (en forma de composición alélica) puede ser por lo menos tan importante como lo es su nivel de diversidad, Estos nuevos elementos descriptivos son ilustrados mediante el uso de datos de DNA de isozima y cloroplasto para una especie de árbol en peligro, el árbol argan de Morocco (Argania spinosa(L.) Skeels). Con estos análisis, el valor de conservación de las poblaciones del árbol argan puede ser apreciado mejor, especialmente para aquellas provenientes de dos grupos aislados del norte del país. Los métodos propuestos para la identificación de áreas prioritarias para la conservación de los recursos genéticos del árbol argan son comparados con aquellos utilizados en el diseño de reservas, donde una de las metas es la maximización de la riqueza de especies.