Utilization of Bamboo by the Giant Panda

Abstract

Two giant pandas were used to assess the utilization of bamboo as a feedstuff. Three 1-week-long digestion trials were conducted during which feed intake and fecal output were recorded. Passage of digesta was measured from both fluid and particulate markers administered at feeding. Results indicate that the giant panda, although highly specialized for the consumption of bamboo, is a very inefficient digester of bamboo. The pandas consumed up to 6% of body weight in dry matter per day, with bamboo dry matter digestibility averaging less than 20%. Apparent digestion coefficients for the structural carbohydrates of bamboo (27% for hemicellulose and 8% for cellulose) indicate that, unlike most herbivores, pandas do not rely heavily on the microbial degradation of plant material to fulfill their nutritional requirements. Additionally, the passage of digesta through the gastrointestinal tract of the panda was extremely rapid, with complete clearance of markers in less than 12 hours. The giant panda seems to have specialized to a feed source high in plant fiber without extensive modification of the digestive tract by selectivity in feeding, effective mastication, ingestion of large quantities, digestion of cellular contents rather than cell walls and rapid fecal excretion of the undigested residue.

Comparative digesta retention patterns in ratites

“…Nevertheless, these reports also indicate that at times, Emus ingest plant material only. The comparison between Ostriches and Emus thus resembles that of mammalian herbivores with a distinct fermentation chamber and long retention times in comparison to giant pandas (Ailuropoda melanoleuca) with their unspecialized guts, pronounced high food intake, particularly short digesta retention, and low fiber digestibility (Dierenfeld et al 1982). In addition, Emus may have a low metabolism to compensate for the lack of extensive plant fiber fermentation (Calder andDawson 1978, Dawson andHerd 1983), but comparative data for ratites do not suggest a difference between Ostriches, Rheas, and Emus in this respect (Crawford andLasiewski 1968, McNab 2009).…”

Evidence of cellulose metabolism by the giant panda gut microbiome

“…It consumes ∼12.5 kg of this highly fibrous plant each day (8), but because it lacks the long intestinal tract characteristic of other herbivores, extensive fermentation is not possible (9). Giant pandas digest only ∼17% of dry matter consumed (8), and have low digestion coefficients for bamboo hemicelluloses (27%) and celluloses (8%) (9).…”

“…It consumes ∼12.5 kg of this highly fibrous plant each day (8), but because it lacks the long intestinal tract characteristic of other herbivores, extensive fermentation is not possible (9). Giant pandas digest only ∼17% of dry matter consumed (8), and have low digestion coefficients for bamboo hemicelluloses (27%) and celluloses (8%) (9). Indeed, the giant panda genome codes for all necessary enzymes associated with a carnivorous digestive system, but lacks the enzyme homologs needed for cellulose digestion (10).…”

Distribution Patterns of Five Mammals in the Jomon Period, Middle Edo Period, and the Present, in the Japanese Archipelago

“…The giant panda's existence revolves around its almost exclusive diet of bamboo. With a gastro-intestinal tract typical of the Carnivora, single stomach, short intestine, and no caecum, the panda only digests on average 17% of the dry matter of its bamboo diet (Dierenfeld et al, 1982, Schaller et al, 1985, Mainka et al, 1989. Cell contents provide most of the digestible nutrients, and pandas digest relatively little of the structural carbohydrates of cell walls.…”

“…Therefore pandas must ingest large amounts (10-18kg) of bamboo daily. Feeding takes most of their waking time (Dierenfeld et al 1982;Schaller et al 1985). Consequently the factors most strongly influencing habitat selection are likely to be food availability and quality.…”