Passage marker excretion in red kangaroo (Macropus rufus), collared peccary (Pecari tajacu) and colobine monkeys (Colobus angolensis, C. polykomos, Trachypithecus johnii)

Abstract

Ruminants are characterized by an efficient particle‐sorting mechanism in the forestomach (FRST) followed by selective rechewing of large food particles. For the nonruminating foregut fermenter pygmy hippo it was demonstrated that large particles are excreted as fast as, or faster than, the small particles. The same has been suggested for other nonruminating foregut fermenters. We determined the mean retention time of fluids and different‐sized particles in six red kangaroos (Macropus rufus), seven collared peccaries (Pecari tajacu) and three colobine monkeys (Colobus angolensis, C. polykomos, Trachypithecus johnii). We fed Co‐EDTA as fluid and mordanted fiber as particle markers (Cr, Ce). Mean (±SD) total tract retention time for fluids, small and large particles was 14±2, 29±10 and 30±9 hr in red kangaroos, 26±2, 34±5 and 32±3 hr in collared peccaries and 57±17, 55±19 and 54±19 hr in colobine monkeys, respectively. Large and small particles were excreted simultaneously in all species. There was no difference in the excretion of fluids and particles in the colobine monkeys, in contrast to the other foregut fermenters. In the nonprimate, nonruminant foregut fermenters, the difference in the excretion of fluids and small particles decreases with increasing food intake. On the contrary, ruminants keep this differential excretion constant at different intake levels. This may be a prerequisite for the sorting of particles in their FRST and enable them to achieve higher food intake rates. The functional significance of differential excretion of fluids and particles from the FRST requires further investigations. J. Exp. Zool. 311A: 647–661, 2009. © 2009 Wiley‐Liss, Inc.

No ‘bypass’ in adult ruminants: Passage of fluid ingested vs. fluid inserted into the rumen in fistulated muskoxen (Ovibos moschatus), reindeer (Rangifer tarandus) and moose (Alces alces)

“…However, similar to findings in this study, indications for a bypass of soluble markers in foregut fermenting primates are lacking so far because in this group, orally applied fluid and particle markers are excreted together (Nijboer et al 2007;Schwarm et al 2009). In adult ruminants, a certain degree of rumen bypass does occur during drinking (but note that the majority of fluid still enters the rumen; Woodford et al 1984).…”

Evolutionary adaptations of ruminants and their potential relevance for modern production systems

“…Consistent with this view, the only geographic region where a large species radiation of non-ruminant foregut fermenters is documented, Australia, is generally marked by low-primary productivity and a mammal population (the marsupials) that is characterised by relatively low metabolic rates (McNab, 2008). In non-ruminant foregut fermenters, particle retention in the foregut is indiscriminate (Schwarm et al, 2008(Schwarm et al, , 2009b, meaning that particles are retained irrespective of their size and digestion status. In contrast, the sorting mechanism in the forestomach of ruminants selectively retains those particles that can be further digested but expels those that already are -thus conceptually allowing a higher intake in ruminants than in non-ruminant foregut fermenters (Clauss et al, 2007b;Schwarm et al, 2009a; Figure 2a).…”

“…Digestive efficiency is mainly determined by food quality, by ingesta retention time and ingesta particle size (Hume, 2005). Ingesta retention and particle size can actually compensate for each other (Clauss et al, 2009b), with longer retention and smaller particles enhancing digestive efficiency. Ingesta retention can be described as a function of gut capacity (Langer and Snipes, 1991) and of food intake (Clauss et al, 2007b).…”

Digesta retention patterns of solute and different-sized particles in camelids compared with ruminants and other foregut fermenters

“…Colobus polykomos Schwarm et al 2009c) in the dataset for MRT 2mm for which values of many different species were available, without the inclusion of herbivore type as a cofactor. The value of the phylogenetic signal (λ) (Pagel 1999), which can be considered a measure of the phylogenetic structure in the dataset, was estimated with maximum likelihood (Revell 2010), using the PGLS command from the package caper (Orme et al 2010).…”

“…Camelids and ruminants both had higher SF 10/2mm FS than NRFF, suggesting convergence in the function of the FS and physiological process (Gordon 1968) that is characterised not only by 'repeated mastication' but also by a density-dependent sorting mechanism in the forestomach (FS) of ruminants and camelids (Lechner-Doll et al 1991). This mechanism is absent in non-ruminant foregut fermenters (Schwarm et al 2008(Schwarm et al , 2009c. In ruminants and camelids, this mechanism ensures that only those particles are ruminated that require further comminution.…”