Energy Intake by Hydropenic Chipping Sparrows (Spizella passerina passerina) Maintained on Different Diets

Moldenhauer, Ralph R.; Taylor, Patricia G.

doi:10.2307/1366564

Cited by 4 publications

(1 citation statement)

References 17 publications

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“…It is possible that by hour 18 of water restriction, WR birds had engaged physiological or behavioral strategies to minimize water loss, reducing the need to elevate metabolic water production and allowing them to spare protein in favor of fat catabolism. Depending on the conditions causing dehydration, birds can reduce water loss by retaining feces in the digestive tract longer to increase water reabsorption or by using adaptive hyperthermy to reduce water lost through evaporative cooling, among other strategies ( Arad et al, 1987 ; Brischoux et al, 2020 ; Gerson et al, 2019 ; Moldenhauer and Taylor, 1973 ; Goldstein and Braun, 1988 ). It should be noted, however, that absolute rates of EWL were higher for both control and WR birds during experiment 2, likely because the respirometry trial was conducted during the day when RMR is greater or because the duration was too short for birds to reach RMR.…”

Section: Discussionmentioning

confidence: 99%

Water restriction increases oxidation of endogenous amino acids in house sparrows (Passer domesticus)

Rogers,

Gerson

2024

Journal of Experimental Biology

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Animals can cope with dehydration in a myriad of ways, both behaviorally and physiologically. The oxidation of protein produces more metabolic water per kJ than that of fat or carbohydrate, and it is well established that birds increase protein catabolism in response to high rates of water loss. However, the fate of amino acids mobilized in response to water restriction has not been explicitly determined. While protein catabolism releases bound water, we hypothesized that water restricted birds would also oxidize the resulting amino acids, producing additional water as a product of oxidative phosphorylation. To test this, we fed captive house sparrows (Passer domesticus) 13C-labeled leucine for 9 weeks to label endogenous proteins. We conducted weekly trials during which we measured the physiological response to water restriction as changes in lean mass, fat mass, metabolism, and the enrichment of 13C in exhaled CO2. If water restricted birds catabolized proteins and oxidized the resulting amino acids, we expected to simultaneously observe greater lean mass losses and elevated δ13Cbreath relative to control birds. We found that water restricted birds catabolized more lean tissue and also had enriched 13Cbreath in response to water restriction, supporting our hypothesis. δ13Cbreath, however, varied with metabolic rate and the length of the water restriction period, suggesting that birds may spare protein when water balance can be achieved using other physiological strategies.

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Section: Discussionmentioning

confidence: 99%

Water restriction increases oxidation of endogenous amino acids in house sparrows (Passer domesticus)

Rogers,

Gerson

2024

Journal of Experimental Biology

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Adjustments of Australian birds to thermal conditions and water scarcity in arid zones

Dawson¹

1981

Ecological Biogeography of Australia

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Evaporative losses of water by birds

Dawson

1982

Comparative Biochemistry and Physiology Part A: Physiology

190

129

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1. Birds lose water in evaporation from the respiratory tract and, in many species, through the skin. Anatomical arrangements in the nasal passages to conservation of water and hear from the expired air in the absence of heat loads. However, most species still expend more water in evaporation than they produce in metabolism when either quiescent or vigorously active. Certain small birds, several of them associated with arid environments, represent exceptions to this and their more favorable situation appears in part to reflect as an ability to curtail cutaneous water loss. 2. Birds typically resort to panting in dealing with substantial heat loads developing in hot environments or accumulated over bouts of activity. In a number of species this form of evaporative cooling is supplemented by gular fluttering. 3. The ubiquitousness of active heat defense appears to reflect more the importance for birds of dealing with heat loads existing following flight or sustained running than any universal affinity for hot climates. Panting can be sustained for hours, despite progressive dehydration and, in some instances, hypocapnia and respiratory alkalosis. The prominent involvement of thermoreceptors in the spinal cord in its initiation is of considerable interest.

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Energy Intake by Hydropenic Chipping Sparrows (Spizella passerina passerina) Maintained on Different Diets

Cited by 4 publications

References 17 publications

Water restriction increases oxidation of endogenous amino acids in house sparrows (Passer domesticus)

Water restriction increases oxidation of endogenous amino acids in house sparrows (Passer domesticus)

Adjustments of Australian birds to thermal conditions and water scarcity in arid zones

Evaporative losses of water by birds

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