A new technique for
insemination of large egg batches with cryopreserved semen in the rainbow
trout
F.
Lahnsteiner, N. Mansour, T. Weismann-2002
Aquaculture, 209(1-4) : 359-367
Abstract:
The present study describes a new method for
fertilization of large egg batches with cryopreserved semen in the rainbow
trout (Oncorhynchus mykiss). Egg batches of 500 g were inseminated
with semen frozen in sixteen 1.2-ml straws (sperm/egg ratio=2.7×106:1).
To be able to handle this number of straws at the same time, they were
connected in self-made, flexible plastic racks into "straw
packages". The straws were filled with diluted semen, and the whole
straw packages frozen in the vapor of liquid nitrogen are 1 cm above the
surface of liquid nitrogen. As the racks remained flexible in liquid
nitrogen, the straw packages could be rolled together for storage in cans of
commercial liquid nitrogen containers. For thawing, the straw packages were
rolled out and thawed in warm water (30 °C, 30 s). Then, they were placed
over the eggs and the straws were cut open to release the semen. The semen
was mixed with the eggs and, thereafter, 250-ml fertilization solution was
added under constant mixing. The fertilization rates were 87.5±1.6% (n=3)
when inseminating 500-g egg batches with cryopreserved semen and 86.7±2.2%
for the fresh semen controls. Only the dry fertilization technique yielded
high fertilization rates when inseminating large egg quantities with
cryopreserved semen, while other investigated parameters (amount of
fertilization solution, arrangement of eggs) had no influence.
(Institute for Zoology, University of Salzburg,
Hellbrunnerstrasse 34, A-5020 Salzburg, Austria, e-mail: Franz.Lahnsteiner@sbg.ac.at)