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Digestive anatomy, physiology, resting metabolism and methane production of captive maras (Dolichotis patagonum)


Clauss, Marcus; Hagen, Katharina B; Frei, Samuel; Ortmann, Sylvia; Lawrenz, Arne; Głogowski, Robert; Fritz, Julia; Flach, Edmund; Kreuzer, Michael (2019). Digestive anatomy, physiology, resting metabolism and methane production of captive maras (Dolichotis patagonum). Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 235:82-89.

Abstract

The digestive physiology of maras (Dolichotis patagonum) has not been investigated in detail. Maras have a particular limb anatomy facilitating a unique cursoriality among rodents. This may also have led to additional adaptations such as a reduced volume of the gastrointestinal tract. We performed macroanatomical measure- ments of, and determined mean particle size along, the digestive tract of 10 semi-free-ranging animals (7.04 ± 1.05 kg). Additionally, we measured CH4 emission in five captive animals (7.67 ± 0.98 kg) fed a diet of pelleted lucerne, and measured food intake, digestibility, and digesta mean retention time (MRT) of a solute and three particle markers (fed at < 2, 10 and 20 mm particle size). The digestive tract contents represented 11.1 ± 1.4% of body mass, similar to other mammals and rodents, and there was slight indication of selective small particle retention in the caecum. Secondary peaks in marker elimination patterns suggested the possibility of caecotrophy. The MRTs were 15.4 h for the solute and 13.6 h, 13.3 h and 13.3 h for the three particle markers, respectively. At a dry matter intake of 61 ± 12 g kg body mass-0.75 d−1, the maras digested organic matter and neutral detergent fibre to 48 ± 8% and 34 ± 10%, respectively, which is in the lower range of results from horses fed on a diet with a similar fibre content. The respiratory quotient (CO2/O2) was 0.93 ± 0.03, the resting metabolic rate 346 ± 35 kJ kg body mass-0.75 d−1, and CH4 emissions averaged at 3.85 ± 0.47 L d−1 and 14.5 ± 5.2 L per kg dry matter intake; this at a CH4/CO2 ratio of 0.042 ± 0.004. Thus, the methane yield was of a magnitude expected for a hypothetical ruminant of this body mass. The results are consistent with the general understanding of hystricomorph rodent digestive physiology, including caecotrophy, but do not indicate a reduction of digestive capacity to support cursoriality. These results, and those obtained from other hystri- comorph rodents, suggest that CH4 production may be more prominent in rodents than previously thought.

Abstract

The digestive physiology of maras (Dolichotis patagonum) has not been investigated in detail. Maras have a particular limb anatomy facilitating a unique cursoriality among rodents. This may also have led to additional adaptations such as a reduced volume of the gastrointestinal tract. We performed macroanatomical measure- ments of, and determined mean particle size along, the digestive tract of 10 semi-free-ranging animals (7.04 ± 1.05 kg). Additionally, we measured CH4 emission in five captive animals (7.67 ± 0.98 kg) fed a diet of pelleted lucerne, and measured food intake, digestibility, and digesta mean retention time (MRT) of a solute and three particle markers (fed at < 2, 10 and 20 mm particle size). The digestive tract contents represented 11.1 ± 1.4% of body mass, similar to other mammals and rodents, and there was slight indication of selective small particle retention in the caecum. Secondary peaks in marker elimination patterns suggested the possibility of caecotrophy. The MRTs were 15.4 h for the solute and 13.6 h, 13.3 h and 13.3 h for the three particle markers, respectively. At a dry matter intake of 61 ± 12 g kg body mass-0.75 d−1, the maras digested organic matter and neutral detergent fibre to 48 ± 8% and 34 ± 10%, respectively, which is in the lower range of results from horses fed on a diet with a similar fibre content. The respiratory quotient (CO2/O2) was 0.93 ± 0.03, the resting metabolic rate 346 ± 35 kJ kg body mass-0.75 d−1, and CH4 emissions averaged at 3.85 ± 0.47 L d−1 and 14.5 ± 5.2 L per kg dry matter intake; this at a CH4/CO2 ratio of 0.042 ± 0.004. Thus, the methane yield was of a magnitude expected for a hypothetical ruminant of this body mass. The results are consistent with the general understanding of hystricomorph rodent digestive physiology, including caecotrophy, but do not indicate a reduction of digestive capacity to support cursoriality. These results, and those obtained from other hystri- comorph rodents, suggest that CH4 production may be more prominent in rodents than previously thought.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Veterinary Clinic > Department of Small Animals
Dewey Decimal Classification:570 Life sciences; biology
630 Agriculture
Scopus Subject Areas:Life Sciences > Biochemistry
Life Sciences > Physiology
Life Sciences > Molecular Biology
Uncontrolled Keywords:Biochemistry, Physiology, Molecular Biology, Digestibility; Hystricomorpha; Mean retention time; Resting metabolic rate; Rodentia
Language:English
Date:1 September 2019
Deposited On:06 Jun 2019 10:39
Last Modified:29 Jul 2020 10:46
Publisher:Elsevier
ISSN:1095-6433
OA Status:Closed
Publisher DOI:https://doi.org/10.1016/j.cbpa.2019.05.023
PubMed ID:31146020
Project Information:
  • : FunderSNF
  • : Grant ID310030_135252/1
  • : Project Title

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