The influence of natural diet composition, food intake level, and body size on ingesta passage in primates.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zürich, Switzerland.
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology (Impact Factor: 2.37). 08/2008; 150(3):274-81. DOI: 10.1016/j.cbpa.2008.03.012
Source: PubMed

ABSTRACT An important component of digestive physiology involves ingesta mean retention time (MRT), which describes the time available for digestion. At least three different variables have been proposed to influence MRT in herbivorous mammals: body mass, diet type, and food intake (dry matter intake, DMI). To investigate which of these parameters influences MRT in primates, we collated data for 19 species from trials where both MRT and DMI were measured in captivity, and acquired data on the composition of the natural diet from the literature. We ran comparative tests using both raw species values and phylogenetically independent contrasts. MRT was not significantly associated with body mass, but there was a significant correlation between MRT and relative DMI (rDMI, g/kg(0.75)/d). MRT was also significantly correlated with diet type indices. Thus, both rDMI and diet type were better predictors of MRT than body mass. The rDMI-MRT relationship suggests that primate digestive differentiation occurs along a continuum between an "efficiency" (low intake, long MRT, high fiber digestibility) and an "intake" (high intake, short MRT, low fiber digestibility) strategy. Whereas simple-stomached (hindgut fermenting) species can be found along the whole continuum, foregut fermenters appear limited to the "efficiency" approach.


Available from: Sylvia Ortmann, Jun 03, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Behavioral observations and small fecal particles compared to other primates indicate that free-ranging proboscis monkeys (Nasalis larvatus) have a strategy of facultative merycism (rumination). In functional ruminants (ruminant and camelids), rumination is facilitated by a particle sorting mechanism in the forestomach that selectively retains larger particles and subjects them to repeated mastication. Using a set of a solute and three particle markers of different sizes (<2, 5 and 8mm), we displayed digesta passage kinetics and measured mean retention times (MRTs) in four captive proboscis monkeys (6-18kg) and compared the marker excretion patterns to those in domestic cattle. In addition, we evaluated various methods of calculating and displaying passage characteristics. The mean±SD dry matter intake was 98±22gkg(-0.75) d(-1), 68±7% of which was browse. Accounting for sampling intervals in MRT calculation yielded results that were not affected by the sampling frequency. Displaying marker excretion patterns using fecal marker concentrations (rather than amounts) facilitated comparisons with reactor theory outputs and indicated that both proboscis and cattle digestive tracts represent a series of very few tank reactors. However, the separation of the solute and particle marker and the different-sized particle markers, evident in cattle, did not occur in proboscis monkeys, in which all markers moved together, at MRTs of approximately 40h. The results indicate that the digestive physiology of proboscis monkeys does not show typical characteristics of ruminants, which may explain why merycism is only a facultative strategy in this species. Copyright © 2015. Published by Elsevier Inc.
    Physiology & Behavior 05/2015; DOI:10.1016/j.physbeh.2015.05.020 · 3.03 Impact Factor
  • Source
    John Sha, Beverly Xue, Jeslyn Ho, Subash Chandran, Azmi Amzah, Serena Oh
    [Show abstract] [Hide abstract]
    ABSTRACT: Considerable variability in dietary and digestive strategies exists across primate taxa. The Singapore Zoo houses a diverse collection of primate species and their diets are formulated with consideration for their natural diets. We evaluated five species of primates with different diets managed by providing different proportions of fruits/vegetables and leaves to replicate their natural diet compositions. We examined the typical proportion of foods provided and consumed by the different species, and compared the nutrients consumed from the respective food types provided. We found that the primates consumed proportions of the two food types provided consistent with the quantities provided. However, all species consumed a higher proportion of fruits/vegetables to leaves than was provided. Species with more folivorous diets often consumed all fruits/vegetables provided to them, but species with more frugivorous diets did not, and supplemented their diets with leaves. More folivorous species obtained the majority of their nutrition from the leaf component of their diet whereas more frugivorous primates obtained relatively equal proportions from both food types. Nutrient selection in preferred food items was not strongly exhibited but the primates generally preferred food items with higher protein and non-structural carbohydrate (NSC) content; species with more folivorous diets preferred leaf items with higher protein–fibre ratio while the converse applied to species with more frugivorous diets. Dietary fibre consumption levels for all species were relatively high; and NSC consumption levels for species with more folivorous diets were close to the recommended upper limits for foregut fermenters. Although current diets provided for these primate species are appropriate, adjustments should be made to refine the proportions and compositions of major food types provided to ensure nutritional goals are met while minimising food wastage. Diets for primates with different dietary specialisations should be customized whenever possible, within the constraints of practical captive management.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To examine the effects of food intake on the gastrointestinal passage time of seeds in the Japanese marten (Martes melampus), we conducted four feeding experiments using captive animals (n = 4). We estimated passage time variables (transit time and mean retention time) of plant seeds (two types) using two different numbers of chicks (single and three) representing two seasons when the animal prey is abundant/scarce. There was no significant relationship between food intake and passage time, and seed type did not affect the passage time variables. Our results were different to those for herbaceous/omnivorous mammals, in which a shorter passage time was observed when food intake increased. The stability in the passage time of the martens could be attributed to the higher level of digestibility of the animal prey. Our data also suggests that martens possess an elastic gut that can expand in volume, which leads to a consistent passage time despite the increase in food intake and enables them to efficiently assimilate nutrients from the consumed food. The results of the present study suggest that the dispersal distance of seeds and defecation site density of martens is influenced by their ranging/activity pattern and not by their digestive physiology.
    Mammal Study 04/2015; 40(1):13-18. DOI:10.3106/041.040.0103 · 0.43 Impact Factor