Seasonal variations of the digestive tract of the Eurasian beaver castor fiber.

Forage availability for wild rodents varies with season. In turn, the composition of food can affect morphometric parameters of the digestive tract. This study was performed in Eurasian beavers (Castor fiber) whose population was close to extinction in most Eurasian countries, but has now increased. Due to the previous low number of studies, information about the effect of forage availability on the digestive tract morphology has previously been lacking. This study was performed using beavers captured from the natural environment during three seasons of different forage availability: winter, summer and autumn. It was found that the diet of the beaver varied during the year; in winter it was dominated by woody material consisting of willow shoots, whereas in summer the diet was primarily herbs, grass and leaves. Season also affected the mass of digested contents of the digestive tract. The digestive content increased in the caecum and colon in winter and autumn, when poor-quality food dominated the beaver's diet. The results indicated that the digestive tract parameters of beavers varied based on the composition of available forage

Digestion in the capybara (Hydrochoerus hydrochaeris)

A study was undertaken to examine the digestion and fermentation in the capybara (Hydrochoerus hydrochaeris) fed either forage or a predominantly concentrate diet. The large volume of digesta (3,66 and 2,73 kg), pH (6,6 and 6,3), NH3 - N (78and 146 mgN/I) and VFA (44 and 41 mM) in the caecum of animals fed forage and high concentrate, respectively, indicate an active hindgut fermentation. This is in accord with previous observations that capybara and sheep have the same ability to digest forage diets.Die vertering en fermentasie van die capybara (Hydrochoerus hydrochaeris) is ondersoek op ruvoer en 'n oorheersende konsentraat dieet. Die groot volume verteringsmateriaal (3,66 en 2,73 kg), pH (6,6en 6,3), NH3 - N (78en 146mgN/I) en VFA (44 en 41 mM) in die sakderm van diere wat ruvoer en hoe konsentraat onderskeidelik gevoer is, dui op 'n aktiewe agterderm fermentasie. Dit stem ooreen met vorige waarnemings dat die skaap en die capybara dieselfde vermoe het om ruvoer diete te verteer.Keywords: Capybara, digestion, fermentation, caecum, particle siz

The digestive performance of mammalian herbivores: why big may not be that much better

1. A traditional approach to the nutritional ecology of herbivores is that larger animals can tolerate a diet of lesser quality due to a higher digestive efficiency bestowed on them by comparatively long ingesta retention times and lower relative energy requirements. 2. There are important physiological disadvantages that larger animals must compensate for, namely a lower gut surface : gut volume ratio, larger ingesta particle size and greater losses of faecal bacterial material due to more fermentation. Compensating adaptations could include an increased surface enlargement in larger animals, increased absorption rates per unit of gut surface, and increased gut motility to enhance mixing of ingesta. 3. A lower surface : volume ratio, particularly in sacciform forestomach structures, could be a reason for the fact that methane production is of significant scope mainly in large herbivores and not in small herbivores with comparably long retention times; in the latter, the substrate for methanogenesis – the volatile fatty acids – could be absorbed faster due to a more favourable gut surface : volume ratio. 4. Existing data suggest that in herbivores, an increase in fibre digestibility is not necessarily accompanied by an increase in overall apparent dry matter digestibility. This indicates a comparative decrease of the apparent digestibility of non-fibre material, either due to a lesser utilization of non-fibre substrate or an increased loss of endogenous/bacterial substance. Quantitative research on these mechanisms is warranted in order to evaluate whether an increase in body size represents a net increase of digestive efficiency or just a shift of digestive focus