الفهرس 
Review of literature
Historical background about semen preservationOnly 14 pages are availabe for public view
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Abstract
Cryopreservation is a non-physiological and complex method that
involves a high level of adaptation of biological cells to the thermal and
osmotic shocks, occur during the dilution, cooling–freezing as well as the
thawing procedures.
During cryopreservation, freeze-thaw damages are unavoidable that
result in reduced semen quality.
The present study was conducted on two native swamp buffalo-bulls
and five breeds of bulls (two Holstein, one Simmental, one Brown-Swiss
one Angus and one Belgian blue), maintained on the experimental farm of
Animal Reproduction Research Institute (ARRI). Their age ranged between 2
and 4.5 years and of body weight 450-700 Kg. Throughout the experimental
period (February – March 2021). each animal received a daily ration
composed of about 15 kg green berseem, 4-5 kg concentrates mixture in
pellet form, and 4-5 kg rice hay. Water was allowed ad libitum. The
animals were kept under similar conditions of nutrition and management.
The semen was collected by AV early in the morning, once weekly from
each bull over a period of six successive weeks. Two successive ejaculates
with about 10 min intervals were obtained from each animal and evaluated
for individual motility (%), sperm concentration, plasma membrane
integrity by HOST, acrosomal status by a dual staining procedure,
mitochondrial activity by MTT test and sperm cell DNA integrity by Comet
assay.
After evaluation , two ejaculates (from each bull) pooled and diluted
with a Tris-based egg yolk extender to obtain a concentration of 40×106
sperm/ml. Samples were cooled slowly to 5oC over a period of 1.5 hours and
Summary and Conclusions
80
loaded in 0.25 ml straws (IMV, France). The straws placed 4 cm above
liquid nitrogen in the vapor phase in a foam box for 15 minutes before being
plunged and stored in liquid nitrogen tank until thawing (one week after
freezing). Thawing occurred at 37o C in a water bath for 30 seconds. All
straws were evaluated for viability index, plasma membrane integrity,
acrosomal intactness, mitochondrial activity and DNA integrities.
The present study revealed a significant (P < 0.05) decrease in most
parameters of cryopreserved semen of buffalo bulls and bull than fresh
semen. The evaluation of cryopreserved semen resulted in loss of sperm
individual motility (26.67% and 29.86%), membrane integrity (29.17% and
28.25%), acrosomal integrities (17.66% and 27.09%) as well as
mitochondrial activity (40.00% and 41.94%) for buffalo bulls and bulls
respectively. Moreover, loss of sperm cell with intact DNA were 4.11%
&1.82 and DNA in head 1.96 and 1.35% , respectively. However, there is
a significant (P < 0.05) increase in DNA of tail (1.95 and 1.35%), tail
length(1.51pixels and 2.13) and Olive tail moment ( 0.09 and 0.17)
respectively.
from this study we can conclude that:
Based on the findings of the present study, it was inferred that both
buffalo bulls and bulls spermatozoa could be frozen in a satisfactory way.
Cryopreservation deserves some changes in motility, functional
integrities of sperm membrane, acrosomes, DNA and mitochondrial activity
of bubaline as well as bovine spermatozoa.
HOS test could be a valuable and practical tool to assess the
functional capacity of fresh and frozen-thawed bubaline and bovine sperm
Summary and Conclusions
81
cells and could be added in the routine analysis of semen samples for
artificial insemination.
DNA integrity of both species (as evaluated by Comet assay) was
better preserved with the current freezing technique.
Moreover, our results indicated that semen from bulls were more
vulnerable to the side effects of freezing as compared to those of buffalo
bulls in terms of individual motility and acrosomal integrity