Respiratory characteristics of Hoplostenum littorale (Siluriformes, Callichthyidae)

Abstract

-Hematological parameters, intraerythrocytic phosphates, hemoglobin, and whole blood Bohr effect of the South American armored catfish Hoplostenum littorale were studied during different seasons of the year. In addition, the degree of dependence on air breathing was determined for this species. The hematological parameters presented seasonal variations, which were not correlated to oxygen, temperature, and water level oscillations. Five anodic being detected, 2,3-DPG was also detected in red blood cells of H. littorale. The latter is an intraerythrocytic phosphate characteristic to red blood cells of mammalians. The increased be related to environmental temperature increase. Whole blood Bohr effect was influenced by water temperature. This study confirms H. littorale to be continuous and not obligate air breather, under all dissolved oxygen level conditions. Key-words: Adaptation, air-breathing behavior, hematology, intraerythrocytic phosphate, blood Bohr effect. Características Respiratórias de Hoplostenum littorale (Siluriformes, Callichthyidae).RESUMO -Os parâmetros hematológicos, os fosfatos intraeritrocitários, a hemoglobina e o efeito Bohr do sangue de Hoplostenum littorale foram estudados em diferentes períodos do ano. Além disso, foi determinado o grau de dependência da respiração aérea nesta espécie. Os parâmetros hematológicos apresentaram variações sazonais, as quais não foram relacionadas com as variações no oxigênio dissolvido, temperatura e nível de água. Além de ATP, GTP e Fe-GTP terem sido detectados nos eritrócitos de H. littorale, 2,3-DPG também foi detectado. Este último é um fosfato intraeritrocitário característico de células vermelhas de mamíferos. O efeito deste composto sobre a afinidade da Hb-O 2 pode estar relacionado com o aumento da temperatura. O efeito Bohr do sangue foi influenciado pela temperatura da água. Este estudo confirma que H. littorale é um respirador aéreo facultativo que utiliza a respiração aérea mesmo em condições normóxicas.Palavras-chave: Adaptação, comportamento da respiração aérea, hematologia, fosfatos intraeritrocitários, efeito Bohr do sangue.Instituto Nacional de Pesquisas da Amazônia, Coordenação de Pesquisas em Aquicultura, Av.

Seasonal hydrology and fish assemblage structure in the floodplain of the lower Amazon River

“…Notably, several species associated with low-water levels have not only adapted to optimise foraging during restricted food supply, but also to extreme environmental conditions such as the low concentrations of dissolved oxygen in the water that are common during this hydrological period (Anjos, De Oliveira, & Zuanon, 2008;Junk, Soares, & Carvalho, 1983;Winemiller, 1989). Many species recognised as possessing behavioural, morphological and/or physiological adaptations to low levels of oxygen were strongly associated with low-water levels (Affonso, 2001;Kramer & McClure, 1982;Saint-Paul & Soares, 1987).…”

Effect of thermal stress on metabolic and oxidative stress biomarkers of Hoplosternum littorale (Teleostei, Callichthyidae)

“…Hoplosternum littorale; endemic to neotropical freshwaters; generally inhabits shallow and lentic environments where they experience great seasonal changes in water physicochemical conditions (Winemiller, 1987). Additionally; the aerial respiration of H. littorale; combined with their tolerance to a wide range of environmental conditions (Affonso, 2001); increases the chances of this species to survive in environments subjected to thermal changes. Its success in occupying extremes environments and their wide distribution all over South America make this species an attractive model to study the physiology and metabolism of fish under thermal stress.…”

Net ion fluxes in the facultative air-breather Hoplosternum littorale (tamoata) and the obligate air-breather Arapaima gigas (pirarucu) exposed to different Amazonian waters

“…The aim of the study reported here was to analyze net ion fluxes in two Amazonian fishes resident in the lakes-a facultative air-breather, Hoplosternum littorale ''tamoata'' (Affonso 2001), and an obligate airbreather, Arapaima gigas ''pirarucu'' (Brauner et al 2004)-exposed to different types of Amazon waters. Both species can be found in BWs and WWs (Afonso 2001;Pereira-Filho and Roubach 2005).…”