Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus
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Publication Date: | 2013 |
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Format: | Article |
Language: | eng |
Source: | Repositório Institucional do INPA |
Download full: | https://repositorio.inpa.gov.br/handle/1/15056 |
Summary: | Oscars are often subjected to a combination of low levels of oxygen and fasting during nest-guarding on Amazonian floodplains. We questioned whether this anorexia would aggravate the osmo-respiratory compromise. We compared fed and fasted oscars (1014 days) in both normoxia and hypoxia (1020 Torr, 4 h). Routine oxygen consumption rates (MO2) were increased by 75% in fasted fish, reflecting behavioural differences, whereas fasting improved hypoxia resistance and critical oxygen tensions (Pcrit) lowered from 54 Torr in fed fish to 34 Torr when fasting. In fed fish, hypoxia reduced liver lipid stores by approximately 50% and total liver energy content by 30%. Fasted fish had a 50% lower hepatosomatic index, resulting in lower total liver protein, glycogen and lipid energy stores under normoxia. Compared with hypoxic fed fish, hypoxic fasted fish only showed reduced liver protein levels and even gained glycogen (+50%) on a per gram basis. This confirms the hypothesis that hypoxia-tolerant fish protect their glycogen stores as much as possible as a safeguard for more prolonged hypoxic events. In general, fasted fish showed lower hydroxyacylCoA dehydrogenase activities compared with fed fish, although this effect was only significant in hypoxic fasted fish. Energy stores and activities of enzymes related to energy metabolism in muscle or gills were not affected. Branchial Na+ uptake rates were more than two times lower in fed fish, whereas Na+ efflux was similar. Fed and fasted fish quickly reduced Na+ uptake and efflux during hypoxia, with fasting fish responding more rapidly. Ammonia excretion and K+ efflux were reduced under hypoxia, indicating decreased transcellular permeability. Fasted fish had more mitochondria-rich cells (MRC), with larger crypts, indicating the increased importance of the branchial uptake route when feeding is limited. Gill MRC density and surface area were greatly reduced under hypoxia, possibly to reduce ion uptake and efflux rates. Density of mucous cells of normoxic fasted fish was approximately fourfold of that in fed fish. Overall, a 1014 day fasting period had no negative effects on hypoxia tolerance in oscars, as fasted fish were able to respond more quickly to lower oxygen levels, and reduced branchial permeability effectively. © 2013. Published by The Company of Biologists Ltd. |
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Boeck, Gudrun deWood, Chris M.Iftikar, Fathima I.Matey, Victoria E.Scott, Graham R.Sloman, Katherine A.Nazar Paula da Silva, Maria deAlmeida-Val, Vera Maria FonsecaVal, Adalberto Luis2020-05-07T14:02:15Z2020-05-07T14:02:15Z2013https://repositorio.inpa.gov.br/handle/1/1505610.1242/jeb.082891Oscars are often subjected to a combination of low levels of oxygen and fasting during nest-guarding on Amazonian floodplains. We questioned whether this anorexia would aggravate the osmo-respiratory compromise. We compared fed and fasted oscars (1014 days) in both normoxia and hypoxia (1020 Torr, 4 h). Routine oxygen consumption rates (MO2) were increased by 75% in fasted fish, reflecting behavioural differences, whereas fasting improved hypoxia resistance and critical oxygen tensions (Pcrit) lowered from 54 Torr in fed fish to 34 Torr when fasting. In fed fish, hypoxia reduced liver lipid stores by approximately 50% and total liver energy content by 30%. Fasted fish had a 50% lower hepatosomatic index, resulting in lower total liver protein, glycogen and lipid energy stores under normoxia. Compared with hypoxic fed fish, hypoxic fasted fish only showed reduced liver protein levels and even gained glycogen (+50%) on a per gram basis. This confirms the hypothesis that hypoxia-tolerant fish protect their glycogen stores as much as possible as a safeguard for more prolonged hypoxic events. In general, fasted fish showed lower hydroxyacylCoA dehydrogenase activities compared with fed fish, although this effect was only significant in hypoxic fasted fish. Energy stores and activities of enzymes related to energy metabolism in muscle or gills were not affected. Branchial Na+ uptake rates were more than two times lower in fed fish, whereas Na+ efflux was similar. Fed and fasted fish quickly reduced Na+ uptake and efflux during hypoxia, with fasting fish responding more rapidly. Ammonia excretion and K+ efflux were reduced under hypoxia, indicating decreased transcellular permeability. Fasted fish had more mitochondria-rich cells (MRC), with larger crypts, indicating the increased importance of the branchial uptake route when feeding is limited. Gill MRC density and surface area were greatly reduced under hypoxia, possibly to reduce ion uptake and efflux rates. Density of mucous cells of normoxic fasted fish was approximately fourfold of that in fed fish. Overall, a 1014 day fasting period had no negative effects on hypoxia tolerance in oscars, as fasted fish were able to respond more quickly to lower oxygen levels, and reduced branchial permeability effectively. © 2013. Published by The Company of Biologists Ltd.Volume 216, Número 24, Pags. 4590-4600Attribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/info:eu-repo/semantics/openAccessOxygenAnimalsAnoxiaBreathingCichlidCritical Oxygen TensionEnergy MetabolismFood DeprivationGillHistologyIon CurrentIon TransportIonoregulationMetabolismOsmoregulationOxygen ConsumptionPhysiologyCritical Oxygen TensionEnergy MetabolismIon FluxIonoregulationRespirationAnimalAnoxiaCichlidsEnergy MetabolismFood DeprivationGillsIon TransportOsmoregulationOxygenOxygen ConsumptionRespirationInteractions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatusinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleJournal of Experimental Biologyengreponame:Repositório Institucional do INPAinstname:Instituto Nacional de Pesquisas da Amazônia (INPA)instacron:INPAORIGINALartigo-inpa.pdfapplication/pdf1999589https://repositorio.inpa.gov.br/bitstream/1/15056/1/artigo-inpa.pdfe1d12db19daf09ab350e6e6ec9b3f82fMD51CC-LICENSElicense_rdfapplication/octet-stream914https://repositorio.inpa.gov.br/bitstream/1/15056/2/license_rdf4d2950bda3d176f570a9f8b328dfbbefMD521/150562020-07-14 10:43:25.618oai:repositorio:1/15056Repositório de PublicaçõesPUBhttps://repositorio.inpa.gov.br/oai/requestopendoar:2020-07-14T14:43:25Repositório Institucional do INPA - Instituto Nacional de Pesquisas da Amazônia (INPA)false |
dc.title.en.fl_str_mv |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
title |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
spellingShingle |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus Boeck, Gudrun de Oxygen Animals Anoxia Breathing Cichlid Critical Oxygen Tension Energy Metabolism Food Deprivation Gill Histology Ion Current Ion Transport Ionoregulation Metabolism Osmoregulation Oxygen Consumption Physiology Critical Oxygen Tension Energy Metabolism Ion Flux Ionoregulation Respiration Animal Anoxia Cichlids Energy Metabolism Food Deprivation Gills Ion Transport Osmoregulation Oxygen Oxygen Consumption Respiration |
title_short |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
title_full |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
title_fullStr |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
title_full_unstemmed |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
title_sort |
Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus |
author |
Boeck, Gudrun de |
author_facet |
Boeck, Gudrun de Wood, Chris M. Iftikar, Fathima I. Matey, Victoria E. Scott, Graham R. Sloman, Katherine A. Nazar Paula da Silva, Maria de Almeida-Val, Vera Maria Fonseca Val, Adalberto Luis |
author_role |
author |
author2 |
Wood, Chris M. Iftikar, Fathima I. Matey, Victoria E. Scott, Graham R. Sloman, Katherine A. Nazar Paula da Silva, Maria de Almeida-Val, Vera Maria Fonseca Val, Adalberto Luis |
author2_role |
author author author author author author author author |
dc.contributor.author.fl_str_mv |
Boeck, Gudrun de Wood, Chris M. Iftikar, Fathima I. Matey, Victoria E. Scott, Graham R. Sloman, Katherine A. Nazar Paula da Silva, Maria de Almeida-Val, Vera Maria Fonseca Val, Adalberto Luis |
dc.subject.eng.fl_str_mv |
Oxygen Animals Anoxia Breathing Cichlid Critical Oxygen Tension Energy Metabolism Food Deprivation Gill Histology Ion Current Ion Transport Ionoregulation Metabolism Osmoregulation Oxygen Consumption Physiology Critical Oxygen Tension Energy Metabolism Ion Flux Ionoregulation Respiration Animal Anoxia Cichlids Energy Metabolism Food Deprivation Gills Ion Transport Osmoregulation Oxygen Oxygen Consumption Respiration |
topic |
Oxygen Animals Anoxia Breathing Cichlid Critical Oxygen Tension Energy Metabolism Food Deprivation Gill Histology Ion Current Ion Transport Ionoregulation Metabolism Osmoregulation Oxygen Consumption Physiology Critical Oxygen Tension Energy Metabolism Ion Flux Ionoregulation Respiration Animal Anoxia Cichlids Energy Metabolism Food Deprivation Gills Ion Transport Osmoregulation Oxygen Oxygen Consumption Respiration |
description |
Oscars are often subjected to a combination of low levels of oxygen and fasting during nest-guarding on Amazonian floodplains. We questioned whether this anorexia would aggravate the osmo-respiratory compromise. We compared fed and fasted oscars (1014 days) in both normoxia and hypoxia (1020 Torr, 4 h). Routine oxygen consumption rates (MO2) were increased by 75% in fasted fish, reflecting behavioural differences, whereas fasting improved hypoxia resistance and critical oxygen tensions (Pcrit) lowered from 54 Torr in fed fish to 34 Torr when fasting. In fed fish, hypoxia reduced liver lipid stores by approximately 50% and total liver energy content by 30%. Fasted fish had a 50% lower hepatosomatic index, resulting in lower total liver protein, glycogen and lipid energy stores under normoxia. Compared with hypoxic fed fish, hypoxic fasted fish only showed reduced liver protein levels and even gained glycogen (+50%) on a per gram basis. This confirms the hypothesis that hypoxia-tolerant fish protect their glycogen stores as much as possible as a safeguard for more prolonged hypoxic events. In general, fasted fish showed lower hydroxyacylCoA dehydrogenase activities compared with fed fish, although this effect was only significant in hypoxic fasted fish. Energy stores and activities of enzymes related to energy metabolism in muscle or gills were not affected. Branchial Na+ uptake rates were more than two times lower in fed fish, whereas Na+ efflux was similar. Fed and fasted fish quickly reduced Na+ uptake and efflux during hypoxia, with fasting fish responding more rapidly. Ammonia excretion and K+ efflux were reduced under hypoxia, indicating decreased transcellular permeability. Fasted fish had more mitochondria-rich cells (MRC), with larger crypts, indicating the increased importance of the branchial uptake route when feeding is limited. Gill MRC density and surface area were greatly reduced under hypoxia, possibly to reduce ion uptake and efflux rates. Density of mucous cells of normoxic fasted fish was approximately fourfold of that in fed fish. Overall, a 1014 day fasting period had no negative effects on hypoxia tolerance in oscars, as fasted fish were able to respond more quickly to lower oxygen levels, and reduced branchial permeability effectively. © 2013. Published by The Company of Biologists Ltd. |
publishDate |
2013 |
dc.date.issued.fl_str_mv |
2013 |
dc.date.accessioned.fl_str_mv |
2020-05-07T14:02:15Z |
dc.date.available.fl_str_mv |
2020-05-07T14:02:15Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/article |
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article |
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publishedVersion |
dc.identifier.uri.fl_str_mv |
https://repositorio.inpa.gov.br/handle/1/15056 |
dc.identifier.doi.none.fl_str_mv |
10.1242/jeb.082891 |
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https://repositorio.inpa.gov.br/handle/1/15056 |
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10.1242/jeb.082891 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Volume 216, Número 24, Pags. 4590-4600 |
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Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ info:eu-repo/semantics/openAccess |
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Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ |
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openAccess |
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Journal of Experimental Biology |
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Journal of Experimental Biology |
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