Aerobic scope in chicken embryos

作者：Ide Satoko T; Ide Ryoji; Mortola Jacopo P^*

来源：Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology, 2017, 212: 81-87.

DOI：10.1016/j.cbpa.2017.07.017

• Gas exchange
• Growth
• Hyperthermia
• Oxygen limitation
• Prenatal metabolism

We investigated the aerobic scope of chicken embryos, that is, the margin of increase of oxygen consumption ((V) over dot(O2)) above its normal value. (V) over dot(O2) was measured by an open-flow methodology at embryonic ages E3, E7, E11, E15, 219 and at E20 at the internal (IP) and external pipping (EP) phases, at the normal incubation temperature (Ta = 38 degrees C), in hypothermia (Ta = 30 degrees C) and in hyperthermia (Ta = 41 and 44 degrees C). In the cold, Q(10) averaged similar to 2 at all ages, except in IP and EP when lower values (similar to 1.5) indicated some degree of thermogenesis. In hyperthermia (38-44 degrees C) Q(10) was between 1 and 1.4. Hyperthermia had no significant effects on (V) over dot(O2) whether the results combined all ages or considered individual age groups, except in IP (in which (V) over dot(O2) increased 8% with 44 degrees C) and EP embryos (+ 13%). After opening the air cell, which exposed the embryo to a higher O-2 pressure, hyperthermic VO2 was significantly higher than in normothermia in 219 (+ 13%), IP (+ 22%) and EP embryos (+ 22%). We conclude that in chicken embryos throughout most of incubation neither heat nor oxygen availability limits the normal (normoxic-normothermic) values of (V) over dot(O2). Only close to hatching O-2-diffusion represents a limiting factor to the embryo's (V) over dot(O2). Hence, embryos differ from postnatal animals for a nearly absent aerobic scope, presumably because their major sources of energy expenditure (growth and tissue maintenance) are constantly maximized.

• 出版日期2017-10
• 单位McGill