Related Experiment Videos
Changes in blood PCO2 and acid-base status in chick embryo between day 4 and 6 of incubation
Insights
Carbon dioxide levels (PCO2) in early chick embryo blood vessels increase during incubation. This study reveals metabolic acidification as PCO2 rises, consistent with later developmental stages.
Area of Science:
- Embryology
- Physiology
- Biochemistry
Background:
- Understanding the physiological changes in avian embryos is crucial for developmental biology.
- Early embryonic development involves complex metabolic and respiratory adjustments.
- Previous data exists for older chick embryos, necessitating research on earlier stages.
Purpose of the Study:
- To measure partial pressure of carbon dioxide (PCO2) in early chick embryos.
- To evaluate blood buffer values and standard bicarbonate concentrations during early development.
- To identify metabolic changes, specifically acidification, in the developing chick embryo.
Main Methods:
- Utilized PCO2 microelectrodes with liquid ion exchangers for precise measurements.
- Conducted in ovo measurements within a hypercapnic environment.
- Analyzed CO2 titration curves to determine blood buffer values and bicarbonate concentrations.
Main Results:
- Mean PCO2 in vitelline veins increased from 4.2 to 7.0 torr between days 4 and 6.
- Mean PCO2 in vitelline arteries rose from 6.9 to 10.6 torr during the same period.
- Buffer values decreased from 28.8 to 21.4 mmol/l, and standard bicarbonate dropped from 29.4 to 24.4 mmol/l, indicating metabolic acidification.
Conclusions:
- Early chick embryos undergo significant changes in PCO2 and acid-base balance.
- Metabolic acidification occurs during the first third of incubation.
- Findings align with previously reported data for older chick embryos, suggesting a continuous developmental trend.
Abstract:
PCO2 was measured in extraembryonic blood vessels of early chick embryos (first third of incubation period) using PCO2 microelectrodes with liquid ion exchanger. Between day 4 and day 6 of incubation mean PCO2 in the vitelline veins increased from 4.2 to 7.0 torr and in the vitelline arteries from 6.9 to 10.6 torr. From the CO2 titration curves obtained in ovo by measurements in hypercapnic environment buffer values of the blood were evaluated (28.8 mmol/l at day 4 and 21.4 mmol/l at day 6). Calculated standard bicarbonate concentration was 29.4 mmol/l at day 4 and decreased to 24.4 mmol/l by day 6 indicating metabolic acidification. These results are compatible to the data previously determined for older embryos.