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Changes in ion content and transport during development of embryonic rainbow trout
Author(s) -
Barrett K. J.,
McDonald D. G.,
O.'Donnell M. J.
Publication year - 2001
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2001.tb00195.x
Subject(s) - biology , rainbow trout , yolk , hatching , embryo , embryogenesis , yolk sac , zoology , trout , ion transporter , biophysics , fishery , fish <actinopterygii> , biochemistry , membrane
Wet mass and water content of four lots of whole eggs did not change throughout embryonic development of rainbow trout Oncorhynchus mykiss. Eggs in all four lots accumulated Na + . Eggs in lots 2 and 4 also accumulated Ca 2+ and Cl ‐ , whereas eggs in lot 1 showed no significant change in Ca 2+ or Cl ‐ and eggs in lot 3 showed no change in Cl ‐ and a small loss of Ca 2+ . Although the Na + content of embryonic tissues increases in the later stages of development, the yolk sac content remained constant, indicating uptake of Na + from the environment. Na+ uptake by whole eggs was non‐saturable, consistent with diffusion of Na + across the chorion into the perivitelline fluid. Na + uptake in dechorionated embryos was saturable, as was Ca 2+ uptake by both whole eggs and dechorionated embryos, consistent with active uptake or facilitated diffusion mechanisms at the surface of embryos. Very low Ca 2+ uptake rates in dechorionated embryos suggest that the Ca 2+ uptake mechanism is not fully developed until after hatching.