Differences in fecal particle size between free‐ranging and captive individuals of two browser species

Hummel, Jürgen; Fritz, Julia; Kienzle, Ellen; Medici, Emília Patrícia; Lang, Stefanie; Zimmermann, W. E.; Streich, W. Jürgen; Clauss, Marcus

doi:10.1002/zoo.20161

Cited by 52 publications

(57 citation statements)

References 18 publications

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“…This framework suggested convergences between feeding types (browser, intermediate feeder, grazer). Many of the resulting hypotheses were later corroborated by statistical evaluations (Pérez-Barbería et al, 2004;Clauss et al, 2008a;Meier et al, 2016). However, in many cases, correlations of investigated characteristics with the percentage of grass in the natural diet included substantial scatter, though being significant.…”

Section: Comparative Ruminant Digestive Morphophysiologymentioning

confidence: 88%

Physiological adaptations of ruminants and their potential relevance for production systems

Clauss

Hummel

2017

R. Bras. Zootec.

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-Herbivores face the dilemma that the level of feed intake is negatively related to factors that determine digestive efficiency, such as thoroughness of ingesta comminution by chewing, and retention of digesta in the digestive tract. Ruminants have evolved particular adaptations to solve this dilemma. Most ruminants share the characteristic of "digesta washing": fluid moves through their digestive tract faster than particles, thus effectively washing very fine particles, such as bacteria, out of the digesta plug. As the forestomach is followed by auto-enzymatic digestion, this allows a continuous, increased harvest of microbes from the forestomach. True rumination only evolved twice, in the camelids and the true ruminants. These both evolved a density-dependent sorting mechanism based on physical separation of the digesta by the process of flotation and sedimentation, ensuring that the process of rumination is applied to large particles. Differences in this sorting mechanism might facilitate a faster digesta processing in true ruminants as compared with camelids. The hallmark of ruminant digestive anatomy is the omasum, in which the fluid required for both digesta washing and the reticular separation mechanism is re-absorbed. In ruminants of the tribe Bovini, the omasum has reached the largest size and this group has a particularly great forestomach fluid throughput. Increasing the degree of digesta washing even more should increase microbial harvest from the forestomach and reduce the susceptibility to acidosis. At the same time, it should result in a metabolic state of the microbiome more tuned towards biomass production and less towards methanogenesis. Enhancing the forestomach fluid throughput by selective breeding could represent a promising way to further advance the productivity of the ruminant digestive tract.

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Section: Comparative Ruminant Digestive Morphophysiologymentioning

confidence: 88%

Physiological adaptations of ruminants and their potential relevance for production systems

Clauss

Hummel

2017

R. Bras. Zootec.

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“…It was previously thought that the lack of stratification resulted in less efficient particle separation, leading to larger faecal particles in browsing than in grazing ruminants kept in zoos (Clauss et al, 2002). More recent results have shown that such differences do not occur if species are measured on their natural diets (Hummel et al, 2008b;Lechner et al, 2010). Correspondingly, no difference in particle discrimination (mean retention of large vs. small particles in the RR) was evident between 'moose-type' and 'cattle-type' ruminants , 2003b;Tschuor and Clauss, 2008;Hummel et al, 2009; inserts on omasum size from Hofmann, 1973).…”

Section: Nutritional Nichementioning

confidence: 96%

“…non-ruminant foregut fermentation, limiting this strategy to herbivores with relatively low metabolic rates (Clauss et al, 2008b). Although this hypothesis remains to be tested, available data suggest that whereas hindgut fermenters display a large range of food intakes and metabolic rates, non-ruminant foregut fermenters are limited to low intakes and low metabolic rates (Figure 2).…”

Section: Foregut and Hindgut Fermentation: Why Ruminants Are Specialmentioning

confidence: 99%

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

Clauss

Hume

Hummel

2010

Animal

176

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Comparative physiology applies methods established in domestic animal science to a wider variety of species. This can lead to improved insight into evolutionary adaptations of domestic animals, by putting domestic species into a broader context. Examples include the variety of responses to seasonally fluctuating environments, different adaptations to heat and drought, and in particular adaptations to herbivory and various herbivore niches. Herbivores generally face the challenge that a high food intake compromises digestive efficiency (by reducing ingesta retention time and time available for selective feeding and for food comminution), and a variety of digestive strategies have evolved in response. Ruminants are very successful herbivores. They benefit from potential advantages of a forestomach without being constrained in their food intake as much as other foregut fermenters, because of their peculiar reticuloruminal sorting mechanism that retains food requiring further digestion but clears the forestomach of already digested material; the same mechanism also optimises food comminution. Wild ruminants vary widely in the degree to which their rumen contents 'stratify', with little stratification in 'moose-type' ruminants (which are mostly restricted to a browse niche) and a high degree of stratification into gas, particle and fluid layers in 'cattle-type' ruminants (which are more flexible as intermediate feeders and grazers). Yet all ruminants uniformly achieve efficient selective particle retention, suggesting that functions other than particle retention played an important role in the evolution of stratification-enhancing adaptations. One interesting emerging hypothesis is that the high fluid turnover observed in 'cattle-type' ruminants -which is a prerequisite for stratification -is an adaptation that not only leads to a shift of the sorting mechanism from the reticulum to the whole reticulorumen, but also optimises the harvest of microbial protein from the forestomach. Although potential benefits of this adaptation have not been quantified, the evidence for convergent evolution toward stratification suggests that they must be substantial. In modern production systems, the main way in which humans influence the efficiency of energy uptake is by manipulating diet quality. Selective breeding for conversion efficiency has resulted in notable differences between wild and domestic animals. With increased knowledge on the relevance of individual factors, that is fluid throughput through the reticulo-rumen, more specific selection parameters for breeding could be defined to increase productivity of domestic ruminants by continuing certain evolutionary trajectories.Keywords: herbivory, hindgut fermenter, foregut fermenter, browser, grazer ImplicationsUnderstanding evolutionary adaptations of ruminants will have an impact on (i) husbandry of captive wild ruminants, many of which cannot be kept or fed as domestic ruminants and (ii) research for continuous refinement of the production potential of domestic ruminants, ...

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“…Sieving time was ten minutes and water throughput 2 l/min. The mean particle size (MPS) was obtained by curve fitting Fritz 8 (TableCurve® 2Dv5.01, Systat Software UK Ltd.) as described by Hummel et al (2008). An average particle size was calculated for each species or, in the case of ostriches, for each gut segment (Table 1).…”

Section: Methodsmentioning

confidence: 99%

Gizzard vs. teeth, it's a tie: food-processing efficiency in herbivorous birds and mammals and implications for dinosaur feeding strategies

et al. 2011

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Particle size reduction is a primary means of improving efficiency in herbivores. The mode of food particle size reduction is one of the main differences between herbivorous birds (gizzard) and mammals (teeth). For a quantitative comparison of the efficiency of food comminution, we investigated mean fecal particle sizes (MPS) in 14 herbivorous bird species and compared these with a data set of 111 non-ruminant herbivorous mammal species. In general MPS increased with body mass, but there was no significant difference between birds and mammals, suggesting a comparable efficiency of food processing by gizzards and chewing teeth. The results lead to the intriguing question of why gizzard systems have evolved comparatively rarely among amniote herbivores. Advantages linked to one of the two food comminution systems must, however, be sought in different effects other than size reduction itself. In paleoecological scenarios, the evolution of ''dental batteries,'' for example in ornithopod dinosaurs, should be considered an advantage compared to absence of mastication, but not compared to gizzardbased herbivory. Abstract. -Particle size reduction is a primary means of improving efficiency in herbivores. The mode of food particle size reduction is one of the main differences between herbivorous birds (gizzard) and mammals (teeth). For a quantitative comparison of the efficiency of food comminution, we investigated mean fecal particle sizes (MPS) in 14 herbivorous bird species and compared these with a data set of 111 non-ruminant herbivorous mammal species. In general MPS increased with body mass, but there was no significant difference between birds and mammals, suggesting a comparable efficiency of food processing by gizzards and chewing teeth.The results lead to the intriguing question of why gizzard systems have evolved comparatively rarely among amniote herbivores. Advantages linked to one of the two food comminution systems must, however, be sought in different effects other than size reduction itself. In paleoecological scenarios, the evolution of "dental batteries," for example in ornithopod dinosaurs, should be considered an advantage compared to absence of mastication, but not compared to gizzard-based herbivory.

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Differences in fecal particle size between free‐ranging and captive individuals of two browser species

Cited by 52 publications

References 18 publications

Physiological adaptations of ruminants and their potential relevance for production systems

Physiological adaptations of ruminants and their potential relevance for production systems

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

Gizzard vs. teeth, it's a tie: food-processing efficiency in herbivorous birds and mammals and implications for dinosaur feeding strategies

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