Effects of environmental hypoxia and hypercarbia on ventilation and gas exchange in Testudines

Autor(es)

Trevizan-Bau, Pedro ^{[1, 2]} ; Abe, Augusto S. ^[3] ; Klein, Wilfried ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Biol, Fac Filosofia Ciencias & Letras Ribeirao Preto, Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Programa Posgrad Biol Comparada, Ribeirao Preto, SP - Brazil

^[3] Univ Estadual Paulista, Inst Biociencias, Rio Claro, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PeerJ; v. 6, JUL 11 2018.
• Citações Web of Science: 2

Resumo

Background. Ventilatory parameters have been investigated in several species of Testudines, but few species have had their ventilatory pattern fully characterized by presenting all variables necessary to understand changes in breathing pattern seen under varying environmental conditions. Methods. We measured ventilation and gas exchange at 25 degrees C in the semi-aquatic turtle Trachemys scripta and the terrestrial tortoise Chelonoidis carbonarius under normoxia, hypoxia, and hypercarbia and furthermore compiled respiratory data of testudine species from the literature to analyze the relative changes in each variable. Results. During normoxia both species studied showed an episodic breathing pattern with two to three breaths per episode, but the non-ventilatory periods (T-NVP) were three to four times longer in T. scripta than in C. carbonarius. Hypoxia and hypercarbia significantly increased ventilation in both species and decreased T-NVP and oxygen consumption in T. scripta but not in C. carbonarius. Discussion. Contrary to expectations, the breathing pattern in C. carbonarius did show considerable non-ventilatory periods with more than one breath per breathing episode, and the breathing pattern in T. scripta was found to diverge significantly from predictions based on mechanical analyses of the respiratory system. A quantitative analysis of the literature showed that relative changes in the ventilatory patterns of chelonians in response to hypoxia and hyperbarbia were qualitatively similar among species, although there were variations in the magnitude of change. (AU)

• Processo FAPESP: 08/57712-4 - Instituto Nacional de Pesquisas em Fisiologia Comparada
• Beneficiário: Augusto Shinya Abe
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/18652-1 - O custo metabólico e mecânico da ventilação em tartarugas
• Beneficiário: Wilfried Klein
• Linha de fomento: Auxílio à Pesquisa - Regular