Postrenal modification of urine in birds

Anderson, Geoff; Braun, Eldon J.

doi:10.1152/ajpregu.1985.248.1.r93

Cited by 15 publications

(7 citation statements)

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“…In addition, the absolute surface area and packing density of microvilli in sparrows also decreased with distance distally along the lower intestine in both species, and this suggests that most reabsorption of ureteral urine may occur along proximal portions of the rectum and possibly the cecae. Many studies have shown that both NaCl and water are reabsorbed in the rectum and cecae (Thomas, 1982;Thomas andSkadhauge, 1982a, 1989;Anderson and Braun, 1985), but no studies of which this author is aware have reported regionally differential absorption.…”

Section: Discussionmentioning

confidence: 99%

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Luminal morphology of the avian lower intestine: Evidence supporting the importance of retrograde peristalsis for water conservation

Casotti

2001

Anat. Rec.

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Tissue from the lower intestine of two species of sparrow, the house sparrow Passer domesticus and savannah sparrow Passerculus sandwichensis was sectioned in an unbiased manner and examined quantitatively using stereology. The tissue was processed for light microscopy, and scanning and transmission electron microscopy to examine the extent to which microvilli enhanced the epithelial surface area of the cecae, rectum, and coprodeum. Parameters measured included individual microvillus surface area, microvilli packing density, and absolute surface area. In both species, the average surface area, packing density, and absolute surface area of microvilli decreased distally along the rectum and coprodeum. All three measured variables were not statistically significant (P Ͼ 0.05) between species. Surface area amplification on the cecae due to microvilli was low, and approximated values equivalent to distal regions of the rectum and coprodeum. In the cecae, microvilli within the savannah sparrow had a significantly higher (P Ͻ 0.05) individual surface area, packing density, and absolute surface area than in the house sparrow. The functional implications of a change in microvilli population are discussed in relation to retrograde peristalsis within the lower intestine of birds.

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Section: Discussionmentioning

confidence: 99%

“…In the lower intestine and cecae, water and sodium chloride are reclaimed by the process of sodium-linked water reabsorption (Thomas, 1982;Thomas andSkadhauge, 1982a, 1989;Anderson and Braun, 1985). Experiments with sparrows show that significant urine modification occurs in hydrated but not in dehydrated sparrows (Goldstein and Braun, 1988).…”

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confidence: 99%

Luminal morphology of the avian lower intestine: Evidence supporting the importance of retrograde peristalsis for water conservation

Casotti

2001

Anat. Rec.

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“…Anderson and Brain showed that 68% of the urate present in urine is degraded in the lower intestine in Gambell's quail (Callipepla gambelii) (Anderson & Brain 1985), with caecal anaerobic bacteria being held responsible (Barnes 1972;Mead 1989). The resulting degraded products are ammonia (NH 3 ), fatty acids and CO 2 (Karasawa 1989;Singer 2003).…”

Section: Factors Influencing the Acidity Of Ex-cretamentioning

confidence: 99%

Dietary habits of urban pigeons (Columba livia) and implications of excreta pH – a review

Spennemann¹,

Watson²

2017

European Journal of Ecology

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Pigeons are considered to be urban pests, causing untold damage to buildings and potentially impacting the health of humans who come into contact with them or their faeces. Pigeon faecal matter has been implicated in both health impacts and building damage, with the acidity of the excreta playing an important role. Purpose of the Review. This paper is a wide-ranging review of the chemical processes of excreta in the pigeon to aid our understanding of the potential problems of pigeons to buildings and human amenity in the urban space. The natural pH of pigeons is shown to vary based on the bird's and age as well as reproductive stage. Key findings of the review. The influences of the altered diet between the rock dove (the wild progenitor of the feral pigeon) and the feral pigeon are detailed, indicating that the human-based diet of urban pigeons most likely causes the feral pigeon excreta to be more acidic than the rock dove excreta. This higher acidity is due in part to diet, but also to potential increases in faecal and/or uric acid volumes due to the low quality of humanbased diets. Again, this area of interest is highly data deficient due to the few number of studies and unspecified dietary intake before pH measurement. Implications of the review. Humans are increasingly concerned about pigeon populations (and presumably their accumulated faeces) in the urban space, and control comprises a large part of the interaction between humans and feral pigeons. This review provides a greater understanding of feral pigeons and the true effects of their excreta. INTRODUCTION ABSTRACTColumba livia; pH; Foraging; Diet; Excreta KEYWORDS

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“…For example, water and Na + excretion rates of chickens (Skadhauge, 1968) and quail (Anderson and Braun, 1985) are higher in ureteral urine than in voided urine (cloacal fluid). Schmidt-Nielson et al (1963) suggested that birds with salt glands might reabsorb Na + and water from the urine in the lower intestinal tract.…”

Section: Kidney Functionmentioning

confidence: 99%

Comparison of renal and salt gland function in three species of wild ducks

Bennett

Hughes

2003

Journal of Experimental Biology

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SUMMARYThree processes central to osmoregulation of marine birds were compared in three species of ducks that differ in habitat affinity, diet and saline tolerance. These processes are filtration of Na+ and water from the plasma by the kidneys, their reabsorption along the renal tubules, and secretion by the salt glands. Barrow's goldeneyes Bucephala islandica, the most marine species, have the highest rates for all three processes and only this species can secrete all the infused salt viathe salt glands. Rates of all three processes are lower in mallards Anas platyrhynchos, the most freshwater species. Following saline acclimation,mallards could excrete all the infused Na+ by a combined Na+ excretion of the kidneys and salt glands. Canvasbacks Aythya valisineria, despite being more saline tolerant than mallards,are unable to excrete all the infused Na+. They produce a large volume of urine (like mallards) that has a low [Na+] (like goldeneyes). Salt gland secretion Na+ concentration did not differ among the three species, but only goldeneyes secrete at a rate sufficient to eliminate all infused Na+via the salt glands. Differences in saline tolerance of these ducks species cannot be fully explained by differences in their filtration, reabsorption and secretion of Na+and water, suggesting that the intestinal tract plays an important role.

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Postrenal modification of urine in birds

Cited by 15 publications

References 0 publications

Luminal morphology of the avian lower intestine: Evidence supporting the importance of retrograde peristalsis for water conservation

Luminal morphology of the avian lower intestine: Evidence supporting the importance of retrograde peristalsis for water conservation

Dietary habits of urban pigeons (Columba livia) and implications of excreta pH – a review

Comparison of renal and salt gland function in three species of wild ducks

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