Cryopreservation
of sea perch (Lateolabrax japonicus) spermatozoa and feasibility for
production-scale fertilization
X.S.
Ji, S.L. Chen, Y.S. Tian, G.C. Yu, Z.X. Sha, M.Y. Xu, S.C. Zhang-2004
Aquaculture, 241(1-4): 517-528
Abstract:
With
the objective of germplasm conservation and cryobank construction, a method
for cryopreserving sea perch (Lateolabrax japonicus, Cuvier) semen in
1.8-ml cryovials was developed. The effects of various extenders,
cryoprotectants, volume of diluted semen on the motility score of post-thaw
spermatozoa were examined. Post-thaw motility of frozen sperm obtained with
extender modified plaice Ringer solution (MPRS) was higher than those
achieved with extenders D-15 and modified Mounib's medium (MMM). With MPRS,
the most effective cryoprotectant was determined to 10% dimethyl sulphoxide
(DMSO). Post-thaw motility of frozen semen was not significantly reduced
when the volume of diluted semen in the cryovial was increased from 0.5 to
1.0 ml (p>0.05). When the sperm/egg ratios varied from 320,000:1
to 20,000:1, fertilization rates of frozen semen cryopreserved for 3 days or
1 year in liquid nitrogen were not significantly different from that of
fresh sperm (p>0.05). In fertilization trials of 230-ml eggs with
frozen semen cryopreserved for 3 days in liquid nitrogen, 84.8%
fertilization rate and 70.1% hatching rate were obtained, which was similar
to control (81.0±2.3% and 87.2±3.1%) (p>0.05). Insemination of
large egg batches (440-ml eggs) with frozen sperm cryopreserved for 1 year
in liquid nitrogen resulted in high fertilization rates (83.5%) and hatching
rates (90.0%) that resembled rates obtained with fresh (control) semen (p>0.05).
Scanning and transmission electron microscopic observation indicated that
while most of frozen–thawed sperm remained morphologically normal, some
exhibited more or less damage, which probably caused the decrease in
motility and fertility of the post-thawed sperm.
(Yellow
Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences,
Qingdao 266071, China, e-mail of S.L. Chen: chensl@ysfri.ac.cn)