Spicing up the menu: evidence of fruit feeding in Galago moholi

The African lesser bushbaby, Galago moholi, is described as a food specialist, feeding exclusively on small arthropods and gum primarily from Acacia karroo trees. We studied a population of G. moholi in a highly fragmented habitat in the southernmost part of its natural distributional range in South Africa. In this habitat, we opportunistically observed bushbabies feeding on fruits of the winter fruiting tree, Pappea capensis. Plot counts of tree composition revealed that although the dominant tree species in the area belonged to the genus Acacia, A. karroo trees were widely absent and gum could only be found in small quantities on other Acacia species. The analysis of P. capensis fruits showed high levels of protein, fat, and energy content, making the fruits a potentially important food source for G. moholi during winter when insect availability is low. Our observation is the first documented case of fruit feeding in G. moholi, suggesting that the species is not a food specialist as previously reported but can supplement its diet with fruit when available.     

The amino acid composition of gum exudates from Prosopis species

The amino acid compositions of the proteinaceous components of the gum exudates from Prosopis alba, P. chilensis, P. glandulosa, P. laevigata, P. torreyana and P. velutina, and for a sample of commercial gum mesquite, are presented. In agreement with data published previously for the polysaccharide components of their gums, only minor differences in composition are shown by these species. The amino acid compositions are characterized by very high proportions of hydroxyproline and by high proportions of proline and serine; these three amino acids account for 62.5% of those present in the gum from Prosopis velutina. The amino acid compositions of these Prosopis gums are remarkably similar to that established recently for the gum from Acacia senegal (gum arabic).     

The sugar and nitrogen content of the gums of Acacia species in the Mountain Ash and Alpine Ash forests of central Victoria and its potential implications for exudivorous arboreal marsupials

Abstract Chemical analysis of the total sugar and total nitrogen content of Acacia dealbata, Acacia obliquinervia and Acacia frigescens gum exudate was completed. These trees were located within stands of 53 year old Mountain Ash, Eucalyptus regnans and Alpine Ash, Eucalyptus delegatensis forest in the Central Highlands of Victoria, southeastern Australia. Values for sugar content ranged from 24 to 68% per sample. Gum samples that were collected in E. regnans forests had a significantly lower (P<0.05) sugar content than those from stands dominated by E. delegatensis. Statistical analyses using Scheffe's S-test indicated that there was a significant difference in the sugar content of gums between A. dealbata and A. frigescens but not between A. dealbata and A. obliquinervia or A. obliquinervia and A. frigescens. Values for the nitrogen content of Acacia gum varied from 0.2 to 0.7% per sample. Statistical analyses revealed that nitrogen content was significantly influenced (P<0.05) by a combination of three interacting factors: (i) Acacia species; (ii) tree diameter; and (iii) forest type. Therefore, the findings of this study indicate that the sugar and nitrogen content of Acacia gum may vary between forest types and tree species. The gum of Acacia species is an important source of food for several species of arboreal marsupials, and differences in sugar and nitrogen content could be a factor potentially influencing the distribution and abundance of these animals.     

Composition and Proposed Nutritional Importance of Exudates Eaten by Saddleback (Saguinus fuscicollis) and Mustached (Saguinus mystax) Tamarins

I provide the first comprehensive data on the composition and mineral content of exudates eaten by saddleback (Saguinus fuscicollis) and mustached tamarins (S. mystax) and assess Garber's (1984; 1993) hypotheses on the potential nutritional importance of exudates in the diet of tamarins. In accordance with his initial findings, nutritional analyses show that the gums consumed are relatively high in calcium and may serve to balance a diet otherwise low in this mineral and high in phosphorus. However, the data on the seasonal variation in the amount consumed do not support the hypothesis that exudates are of particular nutritional importance during the later stages of gestation or lactation for saddleback or mustached tamarins.     

The population of Acacia tree species producing gum arabic in the Karamoja region, Uganda

The study aimed at determining the population status of the different Acacia tree species producing gum arabic in the undisturbed, grazed and cultivated habitats in the Karamoja region, Uganda. A total of 135 sample plots each measuring 20 × 20 m² (0.04 ha) with each habitat having 45 plots were selected and established in the seven counties using a simple random sampling technique. The tree species present, their abundances and sizes were recorded. Twelve Acacia species were identified and a total of 5535 recorded in the sampled area. Out of these, five were gum‐producing acacias. Acacia senegal dominated the acacias in all the seven counties and in all habitats of Karamoja with Acacia nilotica (72.3%), Acacia seyal (13.4%), Acacia sieberiana (4%) and Acacia gerrardii (2.6%). Non‐gum‐producing acacias constituted 7.19% of the total abundance. The tree densities increased with increase in tree size in the undisturbed and grazed habitats but decreased in the cultivated habitat. Most Acacia trees were of large size, an indication of old age and poor regeneration that could affect their future population status. It is recommended that further investigations be carried out into the causes of poor regeneration of Acacia species.     

Chemotaxonomic aspects of some Acacia gum exudates from series Juliflorae*

Data for the chemical composition of the gum exudates from Acacia acradenia, A. aneura, A. acuminata, A. beauverdiana, A. coolgardiensis, A. kempeana, A. microneura, A. resinomarginea, A. stereophylla and A. torulosa are presented. Comparisons with the data reported previously for other species of the series Juliflorae, viz. A. auriculiformis, A. holosericea, A. leptostachya, A. mangium and A. pubifolia confirm that the gums from this series have interesting combinations of chemical properties that are unusual in Acacia. The data do not offer much chemotaxonomic support for the groupings of the Juliflorae suggested by Bentham (1864). On the basis of their gross morphological features, the species under consideration are re-grouped in a way that is also better supported chemically.     

The hydroxyproline content of gum exudates from several plant genera

Amino acid compositions are presented for the proteinaceous components of the gum exudates from Albizia glaberrima, A. sericocephala and A. anthelmintica; Aralia elata; Azadirachta indica; Entada africana; Grevillea robusta; Lannea humilis and L. schimperi; and Moringa oleifera. The gums from four of these genera (Albizia, Azadirachta, Grevillea and Moringa) contain low proportions, and the others contain high proportions, of hydroxyproline. High proportions of hydroxyproline were found previously in gum exudates from genera within the Leguminosae (Acacia, Astragalus and Prosopis), to which must now be added Entada and Leucaena. In contrast, however, Albizia spp. (Leguminosae) have low proportions of hydroxyproline, whereas the non-leguminous genera Aralia and Lannea have high proportions of hydroxyproline.     

An Artificial “gum-tree” for marmosets (Callithrix j. jacchus)

Marmosets (Callithrix, Cebuella) in the wild gouge wells in trees and eat the exudates that accumulate there. An artificial gum-tree was made of wooden dowel and filled with Acacia Senegal exudate (gum arabic) dissolved in water. Three families of marmosets avidly gouged and consumed gum from this device, showing all of the behavioral patterns described in nature. The gum-tree cost little and was easy to make.     

Exudate gums: occurrence,production, and applications

This paper presents a review of the industrially most relevant exudate gums: gum arabic, gum karya, and gum tragacanth. Exudate gums are obtained as the natural exudates of different tree species and exhibit unique properties in a wide variety of applications. This review covers the chemical structure, occurrence and production of the different gums. It also deals with the size and relative importance of the various players on the world market. Furthermore, it gives an overview of the main application fields of the different gums, both food and non-food.     

Feeding behavior of Geoffroy's marmoset (Callithrix geoffroyi) in an Atlantic forest fragment of South-eastern Brazil

We report on the diet and feeding behaviour of a group of Geoffroy's marmosets (Callithrix geoffroyi) in an Atlantic forest fragment in south-eastern Brazil, studied during the period February 1993 to Januaray 1994. Major food categories were gums (68.6%) fruits (15%), and small animal prey (invertebrates 14.6% and vertebrates 0.8%). Dietary changes were observed between the wet and dry seasons, although they were not statistically significant. Insects and gums were consumed throughout the year but fruits were more prevalent in the diet in the wet season. Plant species exploited for their gums includedInga stipularis, followed byAcacia paniculata, Paulinia carpopodia, andBauhinia angulosa. Chemical analysis of the gum of the four species most used all presented high values for carbohydrates and crude proteins. Fruits of an unidentified species of Myrtaceae (sp. 2) were consumed the most. Animal prey consisted mainly of insects, arachnids, snails, and in three cases, lizards and frogs, with orthopterans being the most prevalent insect prey. This study demonstrates thatC. geoffroyi efficiently exploits resources typically available in secondary and disturbed forest habitat. The main threat to the species is forest destruction, degradation, and fragmentation, but the management of small forest fragments may be an effective corservation strategy.     

Composition of the gum from Combretum paniculatum and four other gums which are not permitted food additives.

Only three gum exudates are permitted for pharmaceutical and food use by international regulatory authorities, viz. gum tragacanth (Asiatic Astragalus spp.), gum karaya (Sterculia spp.) and gum arabic [Acacia senegal (L.) Willd.], but a wide range of other tree exudates is used for a variety of uses in their countries of origin. This paper presents analytical data for the gum exudates from Atalaya hemiglauca, Cassine aethiopica, Combretum paniculatum, Sclerocarya birrea, and Pseudocedrela kotschyi. These gums may have local technological applications, but are not recommended for addition to foodstuffs.     

The gum exudates from some closely related Acacia species of the subseries Uninerves racemosae (section phyllodineae)

Australian gum specimens from Acacia aestivalis, A. chrysella, A. jennerae and A. microbotrya (five specimens differing slightly in some morphological characters) have been studied. These species, placed within Bentham's Series 1, subseries 6F (Uninerves racemosae) are closely related, forming part of the recognized A. microbotrya group. The five specimens from A. microbotrya show minor variations, similar in extent to those established previously for gums from other species. The gums from A. chrysella and A. jennerae are similar to those from A. microbotrya in chemical composition. The gum from A. aestivalis differs from those from A. microbotrya, A. chrysella and A. jennerae in two main respects: it is more acidic and has a much higher methoxyl content. Thus significant differences in gum composition can be shown by some species that differ only slightly in morphological characters. Data for the amino acid compositions of the proteinaceous components of the gums from A. aestivalis, A. jennerae and A. microbotrya, differ considerably from those for the gums from other species belonging to the Uninerves racemosae, e.g. A. saliciformis and A. xanthina, which are much more viscous and have higher proteinaceous contents containing much higher proportions of the amino acids commonly involved in linkages with sugars. Of the closely related species studied, A. aestivalis is closer to A. microbotrya than A.jennerae in terms of the amino acid compositions of their gums, a reversal in the relative affinities shown by their polysaccharide parameters. Thus amino acid compositions are of interest chemotaxonomically and also in terms of the tertiary structures of Acacia gum exudates.     

Gum feeder as environmental enrichment for zoo marmosets and tamarins

Tamarins and marmosets are small-bodied social callitrichines. Wild callitrichines feed on exudates, such as sap and gum; particularly, marmosets are mainly gummivores, while tamarins consume gums only occasionally and opportunistically. Zoo marmosets and tamarins are usually provided with gum arabic as an alternative to the exudates normally found in the wild. The aim of this study was to evaluate the effects of a gum feeder on the behavior and well-being of four zoo-managed callitrichines. We studied four cotton-top tamarins (Saguinus oedipus), four red-handed tamarins (S. midas), two pygmy marmosets (Cebuella pygmaea), and three Geoffroy's marmosets (Callithrix geoffroyi) housed at Parco Natura Viva (Italy). We conducted the study over two different periods, a baseline (control, without the gum feeder) and then a gum feeder (when the gum feeder was provided) period. We used continuous focal animal sampling to collect behavioral data, including durations of social and individual behaviors. We collected 240 min of observations per period per study subject, with a total of 3,120 min for all the subjects in the same period and of 6,240 min in both periods. We analyzed data by using nonparametric statistical tests. First, we found that the gum feeder promoted species-specific behaviors, such as exploration, and diminished self-directed behaviors, suggesting an enriching effect on tamarin and marmoset behavior. Moreover, in red-handed tamarins, the provision of the gum feeder reduced the performance of self-directed and abnormal behavior, specifically coprophagy. These results confirm that gum feeders are effective foraging enrichment tools for zoo marmosets and tamarins.     

Tree gum-based renewable materials: Sustainable applications in nanotechnology,biomedical and environmental fields

The prospective uses of tree gum polysaccharides and their nanostructures in various aspects of food, water, energy, biotechnology, environment and medicine industries, have garnered a great deal of attention recently. In addition to extensive applications of tree gums in food, there are substantial non-food applications of these commercial gums, which have gained widespread attention due to their availability, structural diversity and remarkable properties as ‘green’ bio-based renewable materials. Tree gums are obtainable as natural polysaccharides from various tree genera possessing exceptional properties, including their renewable, biocompatible, biodegradable, and non-toxic nature and their ability to undergo easy chemical modifications. This review focuses on non-food applications of several important commercially available gums (arabic, karaya, tragacanth, ghatti and kondagogu) for the greener synthesis and stabilization of metal/metal oxide NPs, production of electrospun fibers, environmental bioremediation, bio-catalysis, biosensors, coordination complexes of metal–hydrogels, and for antimicrobial and biomedical applications. Furthermore, polysaccharides acquired from botanical, seaweed, animal, and microbial origins are briefly compared with the characteristics of tree gum exudates.     

Identification of Intestinal Bacteria Responsible for Fermentation of Gum Arabic in Pig Model

Acacia spp. produce gum exudates, traditionally called gum arabic or gum acacia, which are widely used in the food industry such as emulsifiers, adhesives, and stabilizers. The traditional gum arabic is highly variable with average molecular weights varying from 300,000–800,000. For this reason a standardized sample was used for the present experiments, based on a specific species of gum arabic (Acacia(sen)SUPER GUM^TM EM2). The literature indicates that gum arabic can be fermented by the intestinal bacteria to short chain fatty acid, particularly propionate. However, the bacteria responsible for the fermentation have not been determined. In this study, we used enrichment culture of pig cecal bacteria from the selected high molecular weight specific gum arabic of (M_W 1.77 × 10⁶). We found Prevotella ruminicola-like bacterium as a predominant bacterium that is most likely to be responsible for fermentation of the gum arabic used to propionate.     

Differences among captive callitrichids in the digestive responses to dietary gum

Although many members of the Callitrichidae, a monophyletic family of small, New World monkeys, have been observed to feed on plant exudates, available field data support the generalization that pygmy and common marmosets (Cebuella pygmaea and Callithrix jacchus) feed on gums to a greater extent than most other callitrichids. Because microbial fermentation is required for vertebrates to digest gums, gum-feeding primates may react differently to dietary gum from their relatives that eat little gum. To test this hypothesis, digestion trials were conducted on animals from the two marmoset species, two tamarin species (Saguinus fuscicollis and S. oedipus), and a species of lion tamarin (Leontopithecus rosalia). These species span the range of body sizes within the Callitrichidae. All animals were fed two variations of a homogeneous diet, which differed only in that gum arabic was added to one. Transit time of digesta (TFA) and digestive efficiency (as measured by the coefficients of apparent digestibility of dry matter and energy [ADDM and ADE, respectively]) were compared between diets for each individual. As predicted, the digestive responses of marmosets differed from the responses of the other study species. In marmosets, TFA tended to be longer when gum was added to the diet, while TFA did not change in the other three species. Digestive efficiency decreased in tamarins and lion tamarins with the addition of gum to the diet; marmoset digestive efficiency was unaffected by diet. The results of this research are consistent with the hypothesis that marmosets have digestive adaptations that aid in the digestion of gum that other callitrichids lack. © 1996 Wiley-Liss, Inc.     

The gum exudates from Chloroxylon swietenia,Sclerocarya caffra,Azadirachta indica and Moringa oleifera

Analytical data are presented for the polysaccharide and proteinaceous components of the gum exudates from Chloroxylon swietenia and Sclerocarya caffra, and for the amino acid compositions of the exudates from Azadirachta indica (two specimens) and Moringa oleifera. The gums from C. swietenia and S. caffra contain 4-O-methylglucuronic acid, glucuronic acid, galactose and arabinose; rhamnose is absent. Amino acid analysis shows that proteinaceous material is present in the gums from C. swietenia, S. caffra and M. oleifera despite their low nitrogen content. Hydroxyproline accounts for 28 % of the amino acid content of S. caffra gum. In contrast, A. indica gum has a high nitrogen content but contains very little hydroxyproline.     

Digestive strategy of the south-east African lesser bushbaby, Galago moholi

Galago moholi is a small nocturnal primate, which has a specialised diet of Acacia exudate and insects. Both exudate and insect exoskeletons contain beta-linked polysaccharides that can be used as an energy source by mammals via microbial fermentation. The morphology of the gastro-intestinal tract of G. moholi suggests that the complex, elongate caecum, proximal colon and ansa coli are most likely to be the fermentation compartment. The results of a digesta marker study showed that there was selective retention of the fluid phase of the digesta, a pattern commonly seen in small caecum-fermenting mammals. There was also retention of the particle marker in the gastro-intestinal tract. Comparison to these results with those from other mammals, including other bushbaby species, suggests that this was due to retention of particulate digesta in both the stomach and the ansa coli, a U-shaped loop in the proximal colon. The digestive strategy of the south-east African lesser bushbaby is best described as caeco-ansal fermentation, as the caecum, proximal colon and ansa coli function as distinct fermentation chambers. However, we contend that, because it is soluble polysaccharides in exudates travel with the fluid phase of the digesta, reach the hindgut sooner than particles of the insect exoskeleton, and are fermented faster than particulate digesta, that lesser bushbabies, in spite of their small size (approximately 200 g) are able to include an apparently low-quality food (exudate) in their diet.     

The proteinaceous components of the gum exudates from some phyllodinous Acacia species

Acacia gum exudates are proteinaceous polysaccharides; their protein content ranges from ca 0.2 to 45%.The data presented show that the amino acid compositions of the gums from 12 phyllodinous species (10 from Bentham's sub-series Uninerves racemosae, two from sub-series Juliflorae) also vary considerably, particularly in respect of their hydroxyproline content (55 residues per 1000 residues in A. aestivalis gum, 287 residues per 1000 in A. saliciformis gum). The proportions of some other amino acids, e.g. alanine, aspartic acid, proline and serine also vary considerably, but the proportions of others, e.g. cystine, methionine, histidine, threonine, tyrosine and valine, are remarkably constant. The amino acid composition of gums with a very low protein content (e.g. A. victoriae and A. mycrobotrya) is similar to that for a highly proteinaceous gum (A. tumida). There are, however, considerable differences between the amino acid compositions of the gums from A. saligna and A. pycnantha (South African and Western Australian specimens). This strengthens previous chemotaxonomic evidence, based on the polysaccharide parameters of their gums, that these two species are not as close taxonomically as was originally believed from morphological considerations.     

Efficacy of crude neem seed kernel oil (NSKO) in controlling the tree locust (Anacridium melanorhodon melanorhodon Walker), a serious pest of the gum arabic producing tree (Acacia senegal L. Willd.) in the Sudan

The present study was carried out at Al Semih (western Sudan) (13° 14′ N: 30° 27′ E: Alt. 550 m). The area is part of the gum arabic belt which is heavily populated with farmers who practice shifting cultivation and/or agroforestry where Acacia senegal L. Willd (the main gum arabic producing tree) is dominant. The tree locust (Anacridium melanorhodon melanorhodon Walker (Orthoptera, Acrididae) is a serious pest of A. senegal. Farmers practice agroforestry within the gum belt where they cultivate their crops e.g. millet, groundnut, sesame and sorghum between A. senegal trees. Gum Arabic is an important source of revenue for farmers. Chemical pesticides have been used to control the tree locust. Although the gum belt (where A. senegal grows) is heavily populated, pesticides are used to control the tree locust in the area. The present study was undertaken with the objective of using alternative environmentally safe pesticides. Several doses of neem seed kernel crude oil (NSKO) were tested against the 4^th, 5^th, 6^th instars and the mature tree locust (A. melanorhodon melanorhodon) in a completely randomized block design. Experiments were carried out in cages placed on part of the gum arabic belt. NSKO at high doses (5 and 10% v/v) significantly reduced feeding, moulting and ovipositing of the tree locust and significantly increased the mortality of all developmental stages tested. However, low doses of NSKO had no significant effect on the tree locust.