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

PeerJ

article

Pedro Trevizan-Baú¹  Augusto S. Abe³  Wilfried Klein¹ 

[1] Departmento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo;Programa de Pós-graduação em Biologia Comparada, Universidade de São Paulo;Instituto de Biociências, Universidade Estadual Paulista

关键词: Reptilia;    Normoxia;    Breathing pattern;    Breathing mechanics;    Oxygen consumption;   

DOI  :  10.7717/peerj.5137

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundVentilatory 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.MethodsWe measured ventilation and gas exchange at 25 °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.ResultsDuring normoxia both species studied showed an episodic breathing pattern with two to three breaths per episode, but the non-ventilatory periods (TNVP) were three to four times longer in T. scripta than in C. carbonarius. Hypoxia and hypercarbia significantly increased ventilation in both species and decreased TNVP and oxygen consumption in T. scripta but not in C. carbonarius.DiscussionContrary 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.

【 授权许可】

CC BY