晩成離巣性鳥類胚における心拍リズムの発達(「動物の心拍リズム」国際シンポジウム発表論文選集)

概要

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Mean heart rate(MHR) was determined during incubation and in hatchlings of 14 altricial avian species to investigate 1) if there is a common developmental pattern of heart rate in altricial embryos and 2) if heart rate changes during incubation are correlated with changes in embryonic growth rate. On the basis of normalized incubation MHR increased approximately linearly in 12 of 14 species from as early as 30-40% of incubation to that of pipped embryos. The MHR of hatchlings was equal to or higher than that of pipped embryos in 7 species. Passerine embryos and hatchlings maintained higher MHR in comparison to parrots of similar egg mass, which may reflect phylogenetic differences in development. Embryonic MHR increased at a higher rate while embryonic growth rates were highest during the first 40% of incubation in tit, budgerigar and crow embryos than during subsequent development when relative growth rates decreased. MHR became independent of yolk-free wet mass at a smaller fraction of hatchling mass in budgerigar and crow than in the tit, suggesting that MHR is more likely to increase continuously after 40% of incubation in small altricial species than larger species.
室蘭工業大学の論文
1999-11-30