Adaptive strategies for post-renal handling of urine in birds

Laverty, Gary; Skadhauge, Erik

doi:10.1016/j.cbpa.2008.01.014

Cited by 26 publications

(13 citation statements)

References 67 publications

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“…A retrograde uric acid transport (''urinary reflux'') from the cloaca to the caeca has been suggested for various bird species, including Emus (Skadhauge 1981, Braun and Campbell 1989, Laverty and Skadhauge 2008. The anatomy of Rheas and Emus, with their comparatively short colons, seems to facilitate such a mechanism, whereas its presence seems unlikely in Ostriches due to their long colon (Skadhauge et al 1984) and to date has not been demonstrated using contrast medium studies in Ostriches (Duke et al 1995).…”

Section: Discussionmentioning

confidence: 99%

Comparative digesta retention patterns in ratites

Frei

Ortmann

Reutlinger³

et al. 2015

The Auk

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Ratites differ distinctively in the anatomy of their digestive tract. For example, Ostriches (Struthio camelus) have a particularly long, voluminous colon and long paired caeca, Rheas (Rhea spp.) are characterised by a short colon with particularly prominent paired caeca, and Emus (Dromaius novaehollandiae) -have neither very prominent caeca nor a prominent colon. We tested whether digesta excretion patterns corresponded to these differences in anatomy, expecting Ostriches to have the longest and Emus the shortest digesta retention times, and Rheas possibly showing a selective retention of fluids observed in other birds and mammals with prominent caeca. We used 6 Ostriches (97-123kg), 5 Greater Rheas (R. americana, 22-27kg) and 2 Emus (32-34kg) fed a common diet of alfalfa pellets ad libitum in captivity. Intake per unit of metabolic body mass did not differ between Ostriches and Rheas but was significantly higher in Emus, which also displayed higher defecation frequencies and lower fiber digestibility. Mean digesta retention time for small fiber particles (2 mm) differed significantly among species ; Emu: 1.3-1.8h), but there were no differences between the retention of 2 mm or 8 mm particles or a solute marker within species. The shape of the marker excretion curves corresponded to digesta mixing in the digestive tract of Ostriches and Rheas but not Emus. The calculated dry matter gut fill (% of body mass) was significantly higher in Ostriches (1.6-1.8) than Rheas (0.3-1.0) and Emus (0.2). Ostriches had the highest, and Emus the lowest fecal dry matter concentration. These physiological findings match the differences in digestive anatomy and support the concept that in ratites, herbivory -and hence flightlessness -evolved repeatedly in different ways. ABSTRACT Ratites differ distinctively in the anatomy of their digestive tracts. For example, Common Ostriches (Struthio camelus, hereafter Ostriches) have a particularly long, voluminous colon and long, paired caeca; Rheas (Rhea spp.) are characterized by a short colon with particularly prominent paired caeca; and Emus (Dromaius novaehollandiae) have neither prominent caeca nor a prominent colon. We tested whether digesta excretion patterns corresponded to these differences in anatomy, expecting Ostriches to have the longest and Emus the shortest digesta retention times, and Rheas possibly showing a selective retention of fluids observed in other birds and mammals with prominent caeca. We used 6 Ostriches (97-123 kg), 5 Greater Rheas (R. americana, 22-27 kg), and 2 Emus (32-34 kg) fed a common diet of alfalfa pellets ad libitum in captivity. Intake per unit of metabolic body mass did not differ between Ostriches and Greater Rheas but was significantly higher in Emus, which also displayed higher defecation frequencies and lower fiber digestibility. Mean digesta retention time for small fiber particles (2 mm) differed significantly among species (Ostrich: 30-36 h; Greater Rhea: 7-19 h; Emu: 1.3-1.8 h), but there were no differences between the retention o...

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Section: Discussionmentioning

confidence: 99%

Comparative digesta retention patterns in ratites

Frei

Ortmann

Reutlinger³

et al. 2015

The Auk

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“…No inference could be made on the lack of significant differences with blue and gold, green-winged, and military macaws because of the low power of the statistical tests. The sample size was similar (range, [8][9][10][11][12][13][14][15][16][17] as well as the variability (SD range, 6.2-30.8 mOsm/kg). 5 The overall mean 6 SD of 314 6 14 mOsm/kg for the 3 psittacine birds species was significantly higher than the mean in dogs (300 mOsm/kg; t 5 6.97, P , .001) and humans (282 mOsm/kg; t 5 15.92, P , .001) but not significantly different from the mean in cats (310 mOsm/kg; t 5 2.00, P 5 .05).…”

Section: Discussionmentioning

confidence: 99%

Plasma Osmolality Reference Values in African Grey Parrots (Psittacus erithacus erithacus), Hispaniolan Amazon Parrots (Amazona ventralis), and Red-fronted Macaws (Ara rubrogenys)

Beaufrère

Acierno

Mitchell³

et al. 2011

Journal of Avian Medicine and Surgery

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Birds are routinely presented to veterinarians for dehydration. Success with these cases ultimately depends on providing replacement fluids and re-establishing fluid homeostasis. Few studies have been done to determine reference ranges for plasma osmolality in birds. The goals of this study were to determine reference values for plasma osmolality in 3 species of parrots and to provide recommendations on fluid selection for replacement therapy in these species. Blood samples were collected from 21 adult Hispaniolan Amazon parrots (Amazona ventralis), 21 Congo African grey parrots (Psittacus erithacus erithacus), and 9 red-fronted macaws (Ara rubrogenys), and were placed into lithium heparin containers. Plasma osmolality was measured in duplicate with a freezing point depression osmometer. Summary statistics were computed from the average values. Reference ranges, calculated by using the robust method, were 288-324, 308-345, and 223-369 mOsm/kg in African grey parrots, Hispaniolan Amazon parrots, and red-fronted macaws, respectively. The mean +/- SD values were 306 +/- 7, 327 +/- 7, and 304 +/- 18 mOsm/kg in African grey parrots, Hispaniolan Amazon parrots, and red-fronted macaws, respectively. Comparisons with osmolality values in mammals and values previously reported for psittacine bird species suggest that plasma osmolality is slightly higher in parrots than in mammals, species-specific differences exist, and differences between reported values occur. Overall, fluids with an osmolarity close to 300-320 mOsm/L, such as Normosol-R, Plasmalyte-R, Plasmalyte-A, and NaCl 0.9%, can be recommended in parrots for fluid replacement therapy when isotonic fluids are required.

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“…Onder normale omstandigheden kan in een kuiken tot 36% van het water en 75% van de Na uit de urine gereabsorbeerd worden in het coprodeum, het colon en de caeca (Thomas, 1982). Details over de werkingsmechanismen van de nieren en van de betrokken darmsegmenten worden hier niet uitgewerkt, zie hiervoor reviews van Goldstein and Skadhauge (2000), Laverty and Skadhauge (2008), Svihus et al (2013) en Braun (2015.  Lichaamsgewicht.…”

Section: Waterverliesunclassified

Risicobeoordeling waterverstrekking aan vleeskuikens en vleeskuikenouderdieren

Jong

Koene

Ellen

et al. 2016

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Adaptive strategies for post-renal handling of urine in birds

Cited by 26 publications

References 67 publications

Comparative digesta retention patterns in ratites

Comparative digesta retention patterns in ratites

Plasma Osmolality Reference Values in African Grey Parrots (Psittacus erithacus erithacus), Hispaniolan Amazon Parrots (Amazona ventralis), and Red-fronted Macaws (Ara rubrogenys)

Risicobeoordeling waterverstrekking aan vleeskuikens en vleeskuikenouderdieren

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