F. Lahnsteiner et T. Weismann, Changes in eggs of brown trout, rainbow trout, and grayling during short-term storage, N AM J AQUA, 61(3), 1999, pp. 213-219
Short-term storage of the eggs of rainbow trout Oncorhynchus mykiss, brown
trout Salmo trutta, and grayling Thymallus thymallus was investigated to ex
amine factors that limited egg viability and to compare storage with and wi
thout ovarian fluid. Egg viability was similar after 2 h, but after 4 h, eg
g fertilization rate was lower by 14-26% for eggs stored in ovarian fluid a
nd lower by 23-51% in eggs stored without ovarian fluid. Substitution of a
buffered physiological saline solution for ovarian fluid was tested for bro
wn trout and grayling but did not improve egg viability. The wet weight of
eggs during storage without ovarian fluid decreased significantly. Water in
flux during hardening was higher for eggs stored without ovarian fluid than
in controls and eggs stored with ovarian fluid. However, water loss due to
storage could not be completely compensated, so the wet weight of hardened
eggs that had been stored without ovarian fluid remained lower. Ovarian fl
uid pH and activities of protease during egg storage with ovarian fluid sig
nificantly increased, and peptide levels decreased.