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| Registros recuperados: 12 | |
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| SABAT,PABLO. |
| Para las aves, ambientes salobres como los marinos y los salares, son en la práctica hábitats secos. Cuando las aves beben agua o consumen presas saladas, sus fluidos corporales aumentan la osmolaridad. Para mantener el equilibrio osmótico, las aves tienen que eliminar el exceso de electrolitos ingerido en los alimentos y el agua. Las estrategias adaptativas utilizadas por las aves marinas incluyen la utilización de la glándula de la sal, la cual produce soluciones de excreción más concentradas que el agua de mar. Tanto la fisiología y la plasticidad de la glándula nasal se correlaciona con las características ecológicas de las especies. Además, las aves pueden minimizar el estrés osmótico escogiendo presas hipo-osmóticas, o con menor contenido de agua,... |
| Tipo: Journal article |
Palavras-chave: Glándula de la sal; Función renal; Selección de dieta; Osmoregulacion; Paseriformes. |
| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2000000300004 |
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| HARTMAN BAKKEN,BRADLEY; SABAT,PABLO. |
| Nectar-feeding birds oscillate between avoiding overhydration when they are feeding and preventing dehydration during fasts. Here, we examined how resting rates of total evaporative water loss (TEWL) and metabolic water production (MWP) influence water balance in the green-backed firecrown (Sephanoides sephanoides), a Chilean hummingbird. We hypothesized that a circadian rhythm in TEWL would assuage the dehydration risk that hummingbirds face during the night. However, we did not find support for this idea. In resting hummingbirds, rates of TEWL during the day (54 ±6 µLh-1,n = 8) and night (65 ± 12 h-1, n = 5) were similar. Rates of MWP were also similar between the day (22 ±3 µL h-1, n = 8) and night (23 ± 2 µL h-1, n = 5). MWP rates were significantly... |
| Tipo: Journal article |
Palavras-chave: Circadian rhythm; Evaporative water loss; Hummingbird; Osmoregulation; Water balance. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000300001 |
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| FIGUEROA,DANIELA; OLIVARES,RICARDO; SALABERRY,MICHEL; SABAT,PABLO; CANALS,MAURICIO. |
| We studied the lung diffusion parameters of two species of birds and two species of mammals to explore how structural and functional features may be paralleled by differences in life style or phylogenetic origin. We used two fast-flying species (one mammal and one bird), one running mammal and one bird species that flies only occasionally as models. The harmonic mean thickness of the air-blood barrier was very thin in the species we studied. An exception was the Chilean tinamou Notoprocta perdicaria, which only flies occasionally. It showed an air-blood barrier as thick as that of flightless Galliformes. We found that the respiratory surface density was significantly greater in flying species compared to running species. The estimated values for the oxygen... |
| Tipo: Journal article |
Palavras-chave: Diffusing capacity; Lungs; Flight. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602007000200010 |
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| SABAT,PABLO. |
| It has been postulated that both digestive capacity and intestinal biochemical features are correlated to dietary habits in birds. Therefore, it would be expected to find biochemical constraint to hydrolyze sugars in those species, which predate exclusively on marine invertebrates. In vitro intestinal activities of these enzymes were studied in Cinclodes nigrofumosus (d' Orbigny) and Cinclodes patagonicus (Gmelling). Due to differences in dietary habits between species I predicted the lack of sucrase activity in C. nigrofumosus but not in C. patagonicus. Also, low activities of maltase would be expected in both species. On the other hand due to the considerable amount of proteins and trehalose present in preys, high activities of both trehalase and... |
| Tipo: Journal article |
Palavras-chave: Digestion; Dietary adaptation; Disaccharidases; Aminopeptidase-N; Cinclodes. |
| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2000000200009 |
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| ALDEA,PATRICIA; SABAT,PABLO. |
| We studied the osmoregulatory responses of the granivore Zonotrichia capensis, acclimated to high- and low-protein diets as well as two levels of water intake. We tested whether Z. capensis has the ability to modify the proportion of nitrogenous waste in the excreta when protein intake and water intake varies. After 21 days of acclimation, plasma osmolality was not significantly affected by dietary treatment; however, excreta osmolality was higher in the high-protein group compared to the low-protein group. Nitrogenous wastes in Z. capensis are excreted mainly in the form of uric acid. The proportion of kidney devoted to medullary tissue was 40 % higher in dehydrated birds than in hydrated birds. Excreta osmolality was higher in dehydrated birds, and in... |
| Tipo: Journal article |
Palavras-chave: Granivory; Kidney; Nitrogenous waste; Osmoregulation; Passerines. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000400006 |
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| SABAT,PABLO; MARTÍNEZ DEL RÍO,CARLOS. |
| Passerines lack functional salt glands and to a large extent avoid feeding on marine invertebrates. An exception is Cinclodes nigrofumosus. Previous studies reported that the contents of its gastrointestinal tract had a lower osmolality than seawater suggesting that birds were supplementing their marine invertebrate diet with terrestrial invertebrates and fresh water at certain periods of the year. We report seasonal changes in the diet of C. nigrofumosus at two contrasting coastal localities in Central Chile and document the potential correlation between weather and feeding habits with osmoregulatory features in this species. We expected that C. nigrofumosus would increase its use of osmotically challenging marine dietary sources when fresh water is... |
| Tipo: Journal article |
Palavras-chave: Cinclodes; Isotopes; Renal function; Osmoregulation; Seasonal changes. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2005000200009 |
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| CANALS,MAURICIO; FIGUEROA,DANIELA; SABAT,PABLO. |
| In this report, we explore the matching of structures to functional needs by comparing previously reported data of maximal oxygen consumption and the development of the lung in the leaf-eared mouse Phyllotis darwini in warm and cold environments. We discuss whether the state of structural design is commensurate with functional needs from regulated morphogenesis as predicted by the hypothesis of symmorphosis. We found a close match between respiratory structures and functional needs during postnatal development, expressed as safety factors close to unity. However, in the adult stage the safety factors were greater than two, which suggests that adult animals acquired a structure greater than that required considering their maximum capacities. A high safety... |
| Tipo: Journal article |
Palavras-chave: Metabolism; Ontogeny; Phyllotis darwini; Symmorphosis. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602010000100009 |
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| SABAT,PABLO; FARIÑA,JOSÉ M.; SOTO-GAMBOA,MAURICIO. |
| Feeding on saline marine foods may be especially challenging for passerine birds that lack functional salt glands and have a limited ability to concentrate urine. To reduce the salt load imposed by consumption of marine food these birds may select food with low salt contents and/or increase their intake of freshwater. The genus Cinclodes is particular among passerines because it includes species that inhabit both inland and maritime shores. We analyzed the diet of Cinclodes nigrofumosus and explored the possible relationships between dietary composition and salt load at mesic and arid coastal sites of Chile. From a biogeographical perspective, we hypothesized that freshwater availability is critical to the relationship between diet composition and osmotic... |
| Tipo: Journal article |
Palavras-chave: Cinclodes; Dietary habits; Osmoregulation; Osmotic load. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2003000200017 |
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| SABAT,PABLO; NESPOLO,ROBERTO F; BOZINOVIC,FRANCISCO. |
| Birds living in desert environments have been the preferred models for the study of physiological adaptations to water scarcity. Passerine birds living in marine coastal habitats face similar problems, yet physiological adaptations to water conservation in such species have been poorly documented. We measured total evaporative water loss (TEWL) and rates of oxygen consumption (VO2) in three species of passerine birds dwelling in marine and fresh water habitats. Mass specific total evaporative water loss was significantly lower in the marine species, Cinclodes nigrofumosus, than in species inhabiting areas near freshwater sources. We found a positive relationship between TEWL and VO2. The ratio of TEWL to VO2 (relative evaporative water loss, RTEWL) showed... |
| Tipo: Journal article |
Palavras-chave: Evaporative water loss; Cinclodes; Osmoregulation; Passerines; Salt. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2004000200001 |
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| Registros recuperados: 12 | |
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