Carbon dioxide dissociation and buffering in chicken blood during development
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This study tracks changes in blood carbon dioxide transport and buffering during chick development. These adaptations help chicks manage acid-base balance and meet growing CO2 demands from embryo to adult.
Area of Science:
- Physiology
- Comparative Physiology
- Avian Physiology
Background:
- Acid-base balance is crucial for physiological function.
- Carbon dioxide transport and buffering mechanisms adapt during development.
- Understanding these changes in avian species is important for developmental biology.
Purpose of the Study:
- To investigate developmental changes in blood carbon dioxide dissociation curves.
- To analyze the Haldane effect and buffering indices in developing chicks.
- To correlate these physiological changes with oxygen transport and hematocrit.
Main Methods:
- Blood samples were collected from chicks at various developmental stages (pre-hatching, post-hatching, 8-month-old hens).
- Measurements included carbon dioxide dissociation curves, Haldane effect, buffer values, O2 capacity, and hematocrit.
- Data were analyzed to determine changes in blood gas transport and acid-base status.
Main Results:
- Carbon dioxide dissociation curves shifted upwards during embryonic development until pipping, then downwards post-hatching.
- The Haldane factor increased significantly from incubation to young adulthood.
- Buffering power, O2 capacity, and hematocrit increased during incubation, decreased at hatching, and rose again in adults.
Conclusions:
- Developmental shifts in CO2 dissociation curves and buffering support acid-base homeostasis in chicks.
- These adaptations facilitate efficient CO2 transport and buffering to meet the demands of a growing bird.
- The findings provide insights into the physiological strategies enabling successful avian development.
Abstract:
Carbon dioxide dissociation curves of oxygenated and deoxygenated bloods, the Haldane effect, the buffer value and other blood and true plasma buffering indices, O2 capacity and hematocrit were determined in bloods withdrawn from chicks before, during and after hatching and 8-month-old hens. Blood CO2 dissociation curves shifted upwards in the developing embryo till pipping, and moved downwards after pipping and hatching. In accordance with the position of the CO2 dissociation curves, the true plasma bicarbonate and red cell CO2 standardized to PCO2 = 40 torr changed. The Haldane factor at standard PCO2 increased from 0.12-0.13 on days 10-14 of incubation to 0.34 in young hens. The buffering power changed in parallel with O2 capacity and hematocrit, increasing steadily during incubation, dropping at hatching and then increasing again to the adult value. The observed changes in the CO2 dissociation curves and buffering variables during the development enable the chick to minimize the changes in the acid-base status and are favorable for coping with the increasing demand for CO2 transport and buffering of the developing bird.