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Effects of electromagnetic fields and temperature on avian embryonic growth and oxygen consumption
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|Title:||Effects of electromagnetic fields and temperature on avian embryonic growth and oxygen consumption|
|Abstract:||Domestic fowl embryonic growth, oxygen consumption, body dimensions and organ (including pectoral and leg muscles) dry/wet mass, heart rate, respiratory rate and growth abnormalities were studied at altered incubation temperatures (36 °C,40 °C) and after exposure to 2.0, 1.0 and 0.5 gauss (G) electromagnetic fields (EMF), from the seventh day of incubation to hatching. Embryonic organ growth was promoted when incubation temperature was increased from 38°C (control) to 40 °C, but organ growth was significantly retarded when incubation temperature was decreased from 38°C to 36 °C. Evidence was obtained that some tissues (eyeballs and heart) were "spared" the reduction in growth at 36°C, while the lungs, eyeballs and pectoral muscles were spared the accelerated growth at 40 °C. The maturity of the organs (as assessed by their dry/wet mass ratios) was, like their growth, less at 36°C than at 38 °c and this was particularly evident in leg muscle and liver. Organ maturity was enhanced at 40°C especially in the pectoral muscles and stomach. The hatchability of eggs incubated at 36°C was impaired. Embryonic growth and oxygen consumption were increased after exposure to a 2.0 G EMF but inhibited in the 1.0 G EMF group. There were no significant biological effects of 0.5 G EMF on embryonic growth and oxygen consumption. Deformities were found in the 2.0 G and 1.0 G EMF groups but only in the 2.0 G group did reach a statistically significant level. There were no deformities in the 0.5 G EMF group or any of the control groups. The heart and lungs were spared the enhanced overall growth induced by exposure to a 2 G EMF while the intestine was spared the repression of growth at an EMF of I G. Enhanced organ growth was associated with increased tissue maturity, particularly in pectoral muscle and the intestine. The effects of a 1 G EMF on organ maturity were small but, paradoxically, lung maturity increased. A number of deformities was noted in embryos exposed to 2 G EMF. Incubation at 40°C and exposure to a 2 G EMF both increased embryonic growth while incubation at 36°C and exposure to 1 G EMF both repressed growth, overall. However, there were few similarities in the specific effects of the two growth-promoting/ repressing agents on organ growth and maturity. A major difference between temperature ,and EMF was that they exerted their effects at different stages of embryonic life. No significant effects of either temperature or EMF were observed on heart rates, respiratory rates or tissue histology.|
|Description:||Thesis (Ph. D.)--University of Hawaii at Manoa, 1992.|
Includes bibliographical references (leaves 202-210)
xvii, 210 leaves, bound ill. (some col.) 29 cm
|Rights:||All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.|
|Appears in Collections:||Ph.D. - Biomedical Sciences (Physiology)|
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