1988 Fiscal Year Final Research Report Summary
A closed-circuit continuous measurement system for metabolic rate and physioengineering study on thermoregulation of chick embryos.
| Project/Area Number |
62550294
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
計測・制御工学
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| Research Institution | Muroran Institute of Technology |
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Principal Investigator |
TAZAWA Hiroshi Muroran Institute of Technology, Professor, 工学部, 教授 (40002109)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Yukinori Muroran Institute of Technology, Associate, 工学部, 助手 (00179269)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Avian egg / Embryo / Gas conductance of eggshell / Gas exchange / Thermoregulation / Homeothermic metabolic response / Oxygen consumption |
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| Research Abstract |
(1) A closed-circuit continuous measurement system for oxygen consumption was developed utilizing a microcomputer. The carbon dioxide produced by an embryo was simultaneously measured by detecting the changes in electrical conductivity of the CO_2 absorber which was used to eliminate produced CO_2.
(2) Because the O_2 CO_2 and the heat was exchanged through the eggshell, the effects of gas conductance of the eggshell on the gas exchange, embryonic development, blood gases and hematological variables were investigated first by changing it from the beginning of incubation on for several hours.
(3) The gas exchanger of embryos is the chorioallantoic membrane which is well vascularized inside the eggshell. A distribution of the cardiac output to the embryo and the chorioallantoic circulation was studied based on a circuit model analysis and a nomogram drawn with an aid of computer. The importance of blood flow in an egg's internal flows of heat was evaluated by measuring coolng rates of livi
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ng and killed chicken and quail eggs in air and in helium-oxygen mixture.
(4) The heat loss from eggs when cooling was quantitatively evaluated in developing chick embryos together with heat production. Referring to these data, wa determined the cooling methods and the metabolic response of developing chick embryos were measured. It was found that a feeble homeothermic metabolic response appears in the late chick embryos and it becomes stronger after external pipping. The thyroid hormones and the eggshell gas conductance were suggested to play an important role in thermoregulation developing before hatching in chickens.
(5) The metabolic response to cooling was also investigated in the semi-precocial Brown Noddy embryos at different stages of development. In contract to precocial chickens, the semi-precocial Noddy had no apparent homeothermic response before hatching.
(6) In conjuction wiht studies on embryonic thermoregulation, the basic experiments were made to aim at forwarding the present study to a project elucidating the circulatory functions of developing avian embryos. Less
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