Paracellular nutrient absorption in a gum‐feeding new world primate, the common marmoset Callithrix jacchus

Abstract

The common marmoset is one of the few callitrichid species that is not threatened or endangered in the wild, and is widely used in biomedical research, yet relatively little is understood about its digestive physiology. Dietary specialization on plant exudates has lead to relatively reduced small intestines, yet the common marmoset has exceptional dietary breadth, allowing it to successfully utilize a variety of habitats. We predicted that passive, paracellular nutrient absorption would be used by the common marmoset to a greater extent than in other non-flying mammals. We measured the bioavailability and rates of absorption of two metabolically inert carbohydrates not transported by mediated pathways (L-rhamnose and cellobiose, molecular masses of 164 and 342, respectively) to measure paracellular uptake, and of a non-metabolized D-glucose analog (3-O-methyl-D-glucose) to measure total uptake by both mediated and paracellular pathways. We found high bioavailability of 3-O-methyl-D-glucose (83+/-5%), and much higher bioavailability of the paracellular probes than in similarly sized non-flying mammals (30+/-3% and 19+/-2% for L-rhamnose and cellobiose, respectively). Passive, paracellular nutrient absorption accounts for around 30% of total glucose absorption in common marmosets and intestinal permeability is significantly higher than in humans, the only other species of primate measured to date. This may allow the common marmoset to maintain high digestive efficiency when feeding on higher quality foods (fruit, arthropods, gums with higher proportions of simple sugars), in spite of relatively reduced small intestines correlated with adaptations for fermentative digestion of plant gums. We find no evidence to support, in primates, the hypothesis that reliance on paracellular nutrient absorption should increase with body size in mammals, but suggest instead that it may be associated with small body size and/or taxon-specific adaptations to diet.

Searching for Dental Signals of Exudativory in Galagos

“…It has clearly been shown that exudativorous marmosets and strepsirrhines have specific gut adaptations, such as an enlarged, capacious caecum, to promote digestion of exudates (Power, Chap. 2;Nash 1986;Caton et al 1996;Power and Oftedal 1996;McWhorter and Karasov 2007). Studies on the adaptive morphology of the skull and temporomandibular joint, however, have been equivocal (Ravosa et al, Chap.…”

The Ecology of Exudate Production and Exudate Feeding in Saguinus and Callimico

“…However, callitrichines differ markedly in their exudate feeding adaptations and ecology. Tamarins (Saguinus), lion tamarins (Leontopithecus), and callimicos (Callimico) are described as facultative exudate feeders (i.e., they lack the anatomical specializations of the jaws and teeth required for gouging holes in bark), whereas marmosets (Callithrix, Cebuella, Callibella, and Mico) are considered obligate exudate feeders due to their ability to gouge holes into tree trunks and branches to stimulate the flow of exudates, and morphological adaptations associated with efficient digestion of low quality foods in the ceacum and small intestines (Power and Oftedal 1996;McWhorter and Karasov 2007). As a result, for marmosets, exudates are argued to represent stable, renewable, and available resources throughout the entire year (Ferrari and Lopes Ferrari 1989;Rylands and de Faria 1993;Ferrari and Digby 1996).…”

“…Finally, exudates contain difficult to digest beta-linked polysaccharides (Anninson et al 1994;Power 1996;Power and Oftedal 1996). In this regard, common marmosets and pygmy marmosets have evolved elongated and complex hindguts (Cebuella also is characterized by long gut transit time relative to body mass) (Coimbra-Filho and Mittermeier 1977;Coimbra-Filho et al 1980;Ferrari et al 1993;Caton et al 1996;Power 1996;McWhorter and Karasov 2007), which serve to increase opportunities for fermentation and more efficient digestion of exudates. Although these feeding adaptations are well documented, little is known concerning the productivity or spatial and temporal availability of exudate sites, or of the behavioral tactics used by foragers to encounter and effectively exploit this resource.…”

Carbohydrate absorption by blackcap warblers (Sylvia atricapilla) changes during migratory refuelling stopovers

“…Between samplings, birds were kept in individual cages covered with dark cloth. The standard use of this pharmacokinetic procedure requires sampling from the same individuals for all blood samples and for each individual to receive both gavage and injection treatments (Chang and Karasov, 2004;McWhorter and Karasov, 2007;Tracy et al, 2007). However, because of their small m b , and consequently small blood volume, we were only able to take two blood samples from (N37) and refed (N36) treatments upon initial capture, and during refeeding in the refed treatment.…”