Abstract
We tested the hypothesis that altitude-induced hypocapnia in hens reduces eggshell conductance to water vapor (GH2O). Seven laying hens (Gallus domesticus) native to 1200 m were chronically exposed to high altitude (3800 m), and then to high altitude with sufficient inspired CO2 to relieve hypocapnia (3800 m + CO2). Egg GH2O was measured gravimetrically, shell thickness was measured with a micrometer, and aggregate pore area was calculated from measured values using Fick's law. Comparing results at 1200 m (n = 118) and 3800 m (n = 102), GH2O was reduced from 13.9 ± 0.2 to 12.6 ± 0.2 mg/(d·Torr) (mean ± SE), shell thickness was reduced from 0.297 ± 0.003 mm to 0.287 ± 0.03 mm, and calculated aggregate pore area per egg was reduced from 1.97 ± 0.03 mm2to 1.72 ± 0.03 mm2. When hypocapnia was relieved at 3800 m + CO2 (n = 82), GH2O was reduced even further to 11.1 ± 0.2 mg/(d·Torr), shell thickness increased to 0.305 ± 0.003 mm, and aggregate pore area was reduced 1.61 ± 0.03 mm2. Based on these results we reject our hypothesis. We conclude that hypocapnia is responsible for thin eggshells at altitude. Other physiological stimuli must cause the reductions in eggshell GH2O and pore area.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1-10 |
| Number of pages | 10 |
| Journal | Respiration Physiology |
| Volume | 87 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1992 |
| Externally published | Yes |
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Keywords
- Altitude, egg shell conductance
- Birds, hen
- Egg, shell conductance
- Hypocapnia, egg shell conductance
ASJC Scopus subject areas
- Physiology
- Pulmonary and Respiratory Medicine
Cite this
CO2 and avian eggshell formation at high altitude. / Hempleman, Steven C; Powell, F. L.; Adamson, T. P.; Burger, R. E.
In: Respiration Physiology, Vol. 87, No. 1, 1992, p. 1-10.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - CO2 and avian eggshell formation at high altitude
AU - Hempleman, Steven C
AU - Powell, F. L.
AU - Adamson, T. P.
AU - Burger, R. E.
PY - 1992
Y1 - 1992
N2 - We tested the hypothesis that altitude-induced hypocapnia in hens reduces eggshell conductance to water vapor (GH2O). Seven laying hens (Gallus domesticus) native to 1200 m were chronically exposed to high altitude (3800 m), and then to high altitude with sufficient inspired CO2 to relieve hypocapnia (3800 m + CO2). Egg GH2O was measured gravimetrically, shell thickness was measured with a micrometer, and aggregate pore area was calculated from measured values using Fick's law. Comparing results at 1200 m (n = 118) and 3800 m (n = 102), GH2O was reduced from 13.9 ± 0.2 to 12.6 ± 0.2 mg/(d·Torr) (mean ± SE), shell thickness was reduced from 0.297 ± 0.003 mm to 0.287 ± 0.03 mm, and calculated aggregate pore area per egg was reduced from 1.97 ± 0.03 mm2to 1.72 ± 0.03 mm2. When hypocapnia was relieved at 3800 m + CO2 (n = 82), GH2O was reduced even further to 11.1 ± 0.2 mg/(d·Torr), shell thickness increased to 0.305 ± 0.003 mm, and aggregate pore area was reduced 1.61 ± 0.03 mm2. Based on these results we reject our hypothesis. We conclude that hypocapnia is responsible for thin eggshells at altitude. Other physiological stimuli must cause the reductions in eggshell GH2O and pore area.
AB - We tested the hypothesis that altitude-induced hypocapnia in hens reduces eggshell conductance to water vapor (GH2O). Seven laying hens (Gallus domesticus) native to 1200 m were chronically exposed to high altitude (3800 m), and then to high altitude with sufficient inspired CO2 to relieve hypocapnia (3800 m + CO2). Egg GH2O was measured gravimetrically, shell thickness was measured with a micrometer, and aggregate pore area was calculated from measured values using Fick's law. Comparing results at 1200 m (n = 118) and 3800 m (n = 102), GH2O was reduced from 13.9 ± 0.2 to 12.6 ± 0.2 mg/(d·Torr) (mean ± SE), shell thickness was reduced from 0.297 ± 0.003 mm to 0.287 ± 0.03 mm, and calculated aggregate pore area per egg was reduced from 1.97 ± 0.03 mm2to 1.72 ± 0.03 mm2. When hypocapnia was relieved at 3800 m + CO2 (n = 82), GH2O was reduced even further to 11.1 ± 0.2 mg/(d·Torr), shell thickness increased to 0.305 ± 0.003 mm, and aggregate pore area was reduced 1.61 ± 0.03 mm2. Based on these results we reject our hypothesis. We conclude that hypocapnia is responsible for thin eggshells at altitude. Other physiological stimuli must cause the reductions in eggshell GH2O and pore area.
KW - Altitude, egg shell conductance
KW - Birds, hen
KW - Egg, shell conductance
KW - Hypocapnia, egg shell conductance
UR - http://www.scopus.com/inward/record.url?scp=0026611558&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026611558&partnerID=8YFLogxK
U2 - 10.1016/0034-5687(92)90095-E
DO - 10.1016/0034-5687(92)90095-E
M3 - Article
VL - 87
SP - 1
EP - 10
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
SN - 1569-9048
IS - 1
ER -