Use este identificador para citar ou linkar para este item:
https://repositorio.inpa.gov.br/handle/1/17203
Título: | Air breathing and aquatic gas exchange during hypoxia in armoured catfish |
Autor: | Scott, Graham R. Matey, Victoria E. Mendoza, Julie Anne Gilmour, Kathleen M. Perry, Steven Franklin Val, Vera Maria Fonseca Almeida e Val, Adalberto Luis |
Palavras-chave: | Citrate Synthase Cytochrome C Oxidase Fish Protein Lactate Dehydrogenase Myoglobin Phosphoenolpyruvate Carboxykinase (atp) Pyruvate Kinase Air Anatomy And Histology Animals Brain Breathing Catfish Gill Hypoxia Liver Metabolism Oxygen Consumption Pathophysiology Physiology Microscopy, Electron, Scanning Muscle, Skeletal Ultrastructure Air Animal Brain Catfishes Citrate (si)-synthase Electron Transport Complex Iv Fish Proteins Gills Hypoxia L-lactate Dehydrogenase Liver Microscopy, Electron, Scanning Muscle, Skeletal Myoglobin Oxygen Consumption Phosphoenolpyruvate Carboxykinase (atp) Pyruvate Kinase Respiration |
Data do documento: | 2017 |
Revista: | Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology |
É parte de: | Volume 187, Número 1, Pags. 117-133 |
Abstract: | Air breathing in fish is commonly believed to have arisen as an adaptation to aquatic hypoxia. The effectiveness of air breathing for tissue O2 supply depends on the ability to avoid O2 loss as oxygenated blood from the air-breathing organ passes through the gills. Here, we evaluated whether the armoured catfish (Hypostomus aff. pyreneusi)—a facultative air breather—can avoid branchial O2 loss while air breathing in aquatic hypoxia, and we measured various other respiratory and metabolic traits important for O2 supply and utilization. Fish were instrumented with opercular catheters to measure the O2 tension (PO2) of expired water, and air breathing and aquatic respiration were measured during progressive stepwise hypoxia in the water. Armoured catfish exhibited relatively low rates of O2 consumption and gill ventilation, and gill ventilation increased in hypoxia due primarily to increases in ventilatory stroke volume. Armoured catfish began air breathing at a water PO2 of 2.5 kPa, and both air-breathing frequency and hypoxia tolerance (as reflected by PO2 at loss of equilibrium, LOE) was greater in individuals with a larger body mass. Branchial O2 loss, as reflected by higher PO2 in expired than in inspired water, was observed in a minority (4/11) of individuals as water PO2 approached that at LOE. Armoured catfish also exhibited a gill morphology characterized by short filaments bearing short fused lamellae, large interlamellar cell masses, low surface area, and a thick epithelium that increased water-to-blood diffusion distance. Armoured catfish had a relatively low blood-O2 binding affinity when sampled in normoxia (P50 of 3.1 kPa at pH 7.4), but were able to rapidly increase binding affinity during progressive hypoxia exposure (to a P50 of 1.8 kPa). Armoured catfish also had low activities of several metabolic enzymes in white muscle, liver, and brain. Therefore, low rates of metabolism and gill ventilation, and a reduction in branchial gas-exchange capacity, may help minimize branchial O2 loss in armoured catfish while air breathing in aquatic hypoxia. © 2016, Springer-Verlag Berlin Heidelberg. |
DOI: | 10.1007/s00360-016-1024-y |
Aparece nas coleções: | Artigos |
Arquivos associados a este item:
Não existem arquivos associados a este item.
Os itens no repositório estão protegidos por copyright, com todos os direitos reservados, salvo quando é indicado o contrário.