Temperature effects on blood gases in embryonic American alligators (Alligator mississippiensis)

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Molecular & integrative physiology, 2024-11, Vol.297, p.111733, Article 111733
• Main Authors: Crossley, Dane A., Crossley, Janna L., Conner, Justin L., Smith, Brandt, Elsey, Ruth, Nelson, Derek, Wang, Tobias
• Format: Article
• Language: English
• Subjects: Acid-base balance; Alligators and Crocodiles - blood; Alligators and Crocodiles - embryology; Alligators and Crocodiles - physiology; Animals; Blood Gas Analysis; Blood gases; Blood Glucose - metabolism; Carbon Dioxide - blood; Chorioallantoic Membrane - blood supply; Development; Egg; Embryo, Nonmammalian; Environment; Hydrogen-Ion Concentration; Oxygen - blood; Oxygen - metabolism; Programming; Reptile; Temperature
• ISSN: 1095-6433; 1531-4332; 1531-4332
• DOI: 10.1016/j.cbpa.2024.111733

Numerous studies report on the influence of temperature on blood gases in ectothermic vertebrates, but there is merely a cursory understanding of these effects in developing animals. Animals that develop in eggs are at the mercy of environmental temperature and are expected to lack the capacity to regulate gas exchange and may regulate blood gases by means of altered conductance for gas exchange. We, therefore, devised a series of studies to characterize the developmental changes in blood gases when embryonic alligators were exposed to 25, 30 and 35 °C. To determine how blood parameters were impacted by changes in embryonic temperature, blood was sampled from the chorioallantoic membrane artery. The blood in the chorioallantoic membrane artery is a mixture of oxygen-poor and oxygen-rich blood, which based on the embryonic vascular anatomy may reflect blood that perfuses the chemoreceptors of the developing animal. Our findings indicate that following a 48 h exposure to 25 °C or 35 °C, there was a positive relationship between CAM artery blood PO2, PCO2 and glucose. However, blood pH suggests embryonic alligators lack an acute regulatory mechanism for adjusting blood pH. •Temperature does not exhibit the predicted effect on embryonic blood pH.•CAM arterial blood pO2 increases with temperature in embryonic alligators.•CAM arterial pCO2 increases with temperature in embryonic alligators.•CAM arterial O2 content is not affected by temperature in embryonic alligators.