Grass carp ova retention in
the body cavity after ovulation: Ova composition and development capability
of eggs and alevins
M.
Kharroubi, M. Droussi, A. Badri, A. Bouzidi, E. Elboustani-2002
Bulletin
Francais de la Peche et de la Pisciculture, 365(66): 507-523
(from Current Contents)
Abstract :
To investigate the effects of allowing the eggs to be
retained by the grass carp within the abdominal cavity after ovulation, eggs
of 15 females (3-5.6 kg) were obtained at increasing periods of time after
ovulation (0, 30, 60, 90 and 120 min).
For each time of ova stripping, the fertilization rate, the embryonic
survival rate, the hatching rate and the total length of alevins until 5
weeks after hatching (L1=total length 2 weeks after hatching, L2=total
length 3 weeks after hatching, L3=total length 4 weeks after hatching,
L4=total length 5 weeks after hatching) are determined. There was no
significant differences between those biological parameters recorded just
after ovulation and those recorded 120 min after ovulation.
Ova were analyzed for dry weight, water, ashes and levels of total proteins,
total lipids, phospholipids, carbohydrates, calcium and iron. The above
aspects of egg composition remained constant when the ova are retained in
the abdominal cavity for 2 hours after ovulation.
These results indicate that the in vivo retention of grass carp ova for 2
hours after ovulation has no effect neither on their biochemical composition
nor on egg viability, nor on embryonic survival nor on hatching nor on the
growth (total length of alevins until 5 weeks after hatching). The lack of
changes in the composition of ova during their retention in ovario may
explain that we still obtain satisfactory rates of viability 2 hours after
ovulation and that the growth of alevins is not influenced. However, the
composition of ova, the developmental capability of eggs and the growth of
alevins show a high variability between females (p<0.05 for each
investigated parameter).