Gastrointestinal tract of the brown kiwi (Apteryx mantelli)

Abstract

The caeca of the brown kiwi Apteryx mantelli increased in length isometrically with body mass, but wall mass and thus mucosal thickness increased allometrically. Kiwi caeca are sacculate, with greater thickness of mucosa in the proximal portions. The caecal mucosa is similar to the small intestinal mucosa, with welldeveloped mucosal folds, villi, and crypts of Lieberk¨uhn or intestinal glands. The solid matter in caecal digesta contained disproportionately large quantities of material that was not retained by a 75 mm sieve. The per cent of incombustible material (total ash) within the caeca digesta did not differ significantly from those within adjacent small intestinal or rectal segments. The fine particles within the caeca were not composed of fine crystalline uric acid; chemical analyses showed only low levels of uric acid in caecal digesta. These findings indicate that the caeca of this flightless insectivorous ratite are a site for the sequestration and fermentative digestion of fine particulate material, such as plant fibre, fragmented chitin or uric acid crystals.

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“…In several caecum fermenters, by contrast, solutes are retained longer than particles, which is commonly interpreted as an indication of a wash-back mechanism Sakaguchi 1991, Franz et al 2011). A similar pattern has been reported for one small herbivorous bird, the Rock Ptarmigan (Lagopus mutus; Gasaway et al 1975), and has been suggested for another ratite with a large caeca, the North Island Brown Kiwi (Apteryx mantelli), based on the composition of the contents of different gut sections (Potter et al 2006). One could therefore predict that Rheas, with their comparatively large caeca, should display longer solute than particle retention times, and that Ostriches should display a more distinct difference between solute and particle markers than Emus.…”

An exploratory analysis of the suitability of diets fed to a flightless insectivore, the North Island brown kiwi (Apteryx mantelli), in New Zealand

“…Chitin may be digested by animals that possess intestinal chitinase [Jeuniaux, 1962;Graffam et al, 1998;Smith et al, 1998;Whitaker et al, 2004] and thereby potentially contribute to the energy budget or the maintenance of microflora in the large intestine of a number of insectivores. However, it is not known whether kiwi possess such chitinase activity either in their caeca [Potter et al, 2006] or in any other part of their gastrointestinal tract.…”

Macroanatomical and histological study of caecum of the guinea fowl (Numida meleagris) using light and scanning electron microscopy

“…Sarı and Kurtdede (2007) reported that the caecum is consistently resistant to bacterial and non-bacterial antigens, therefore, the caecum should be protected against these antigens. Because almost half of the lymph follicles in caecum are collected in the caecal tonsils, the function of cecal tonsil may be to protect the caecum against microorganisms entering it (Potter et al 2006). All the above data show that the caecum is an important organ of the immune system in poultry species.…”

“…The basis caeci region of the caecum is a thickwalled structure with a narrow lumen and forms the longest part of caecum (Chen et al, 2002;Karadağ and Nur, 2002;Abas et al, 2013). The caecum is an important organ in the digestive system, because it is responsible for cellulose digestion and immune cell production (Karadağ and Nur, 2002;Potter et al 2006). In quails presence of villi was not reported in the corpus caeci and apex.…”