Digestive physiology of captive capybara (Hydrochoerus hydrochaeris)

Abstract

The capybara (Hydrochoerus hydrochaeris), the largest living rodent, probably has a “mucus‐trap” colonic separation mechanism. To test this hypothesis, we measured the mean retention time of a solute marker (MRTSolute), 2 mm (MRT2 mm), 10 mm (MRT10 mm), and 20 mm (MRT20 mm) particle markers and nutrient digestibility in adult captive capybaras (27–52 kg body mass (BM), 2–11 yr). In addition, total gut fill and the selectivity factor (MRTSolute/MRT2 mm) were calculated, and mean faecal particle size and metabolic fecal nitrogen of captive capybaras were compared to those of free‐ranging specimens. Finally, we also measured methane production in one animal. The MRT2 mm (29.2 ± 8.2 hr) was different (p < 0.01) from MRTSolute (37.0 ± 13.1 hr), MRT10 mm (36.5 ± 8.2 hr), and MRT20 mm (35.1 ± 9.6 hr). The selectivity factor (1.26 ± 0.30) was in the range considered typical for a “mucus‐trap” colonic separation mechanism. The estimated total gut fill was 1.50 ± 0.37% and 1.73 ± 0.25% of BM calculated from the results of the 2‐mm and 10‐mm particle markers, respectively. The CH4 emission was 13.7 L/day. Captive capybaras had greater mean fecal particle size (0.44 ± 0.06 vs. 0.29 ± 0.05 mm, p < 0.001) and metabolic fecal nitrogen (65.5 ± 3.91 vs. 46.8 ± 10.5% of fecal nitrogen, p < 0.001) than free‐ranging capybaras. Organic matter digestibility decreased less steeply with increasing dietary crude fiber content in capybaras as compared to published data from rabbits or guinea pigs. Accordingly, the digestive physiology of the capybara is characterized by a comparatively high fiber digestibility, with a “mucus‐trap” colonic separation mechanism, allowing capybaras to thrive on forage‐only diets.

Trichuris spp. in Animals, with Specific Reference to Neo-Tropical Rodents

“…Lall et al [96] summarized these animals as semi-aquatic herbivorous rodents that practice cecotrophy. These animals are hindgut fermenters that possess a mucus trap separation mechanism [109]. Various parasites have been found in the capybara, but the majority of research views these animals as reservoirs for specific pathogens that have zoonotic potential or can cause disease in domestic livestock species.…”

Gut microbiome of the largest living rodent harbors unprecedented enzymatic systems to degrade plant polysaccharides

“…The capybara ( Hydrochoerus hydrochaeris ) is the largest living rodent, typically found in the Pantanal wetlands and Amazon basin, and it is also known as “the master of the grasses” due to its diet based on gramineous and aquatic plants. In this animal, the fermentation takes place in the cecum that corresponds to almost three-quarters of the gastrointestinal tract, reaching a digestive efficiency comparable to that of ruminants 12 . Moreover, as a strategy to maximize absorption of nutrients derived from bacterial fermentation, capybara can eat their cecotropes, a specific type of soft excreta 13 .…”

Gut Microbiome of the Amazon Master of the Grasses Harbors Unprecedented Enzymatic Strategies for Plant Glycans Breakdown

“…Capybara (Hydrochoerus hydrochaeris) is the largest living rodent throughout found in Pantanal wetlands and the Amazon basin, which is also known as "Master of the grasses" due to its diet. In this animal, the fermentation takes place in the cecum, which corresponds to almost three quarters of the digestive tract, reaching a digestive e ciency comparable to that of ruminants (12). Preliminary characterization of capybara cecum microbiome indicated that the most abundant commensal microbes were from Firmicutes and Proteobacteria phyla, with an unusual low abundance of Bacteroidetes (13), not expected for a typical mammalian hindgut fermenter.…”