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Research
6.
Effects of dietary urea on timing of embryo
cleavages and blood components in mice -
A. A. Mohammed, A. H. Attaai
Vet World. 2011; 4(8): 360-363
doi: 10.5455/vetworld.2011.360-363
Abstract
The objectives of the present study were to
investigate the effects of dietary urea
supplementation (1.0% and 3.0%) on oocytes
quality, timing expected of embryo cleavages,
offspring numbers and weights, blood components
and rectal temperature in mice. Sixty of growing
albino mice were classified into three groups; the
control group was given basal control diet and the
other two groups were fed on basal control diet
supplemented with 1.0% and 3.0% urea. Body weights
were recorded at the beginning and after 5 weeks.
Thereafter, five female mice of each group were
injected with 7.5 IU of pregnant mare serum
gonadotropin (PMSG) for determination of oocyte
quality after 48h of injection. The fifteen female
mice of each group were injected with 7.5 IU of
PMSG followed by 7.5 IU of human chorionic
gonadotropin (hCG) after 48h and mated with males
of proven fertility. Five mated females of each
group were used for determination of embryo
cleavages to four cell stage and the other five
mated females were used for determination of
embryo cleavages to eight cell stage upon 59-60
and 70 h of hCG injection, respectively. Rectal
temperatures were recorded and blood samples were
collected. The remaining five mated females of
each group were left for parturition. The
offspring number, litter size and male:female
ratio were recorded. Hematocrit and hemoglobin
concentrations were determined in blood whereas
urea, total protein, albumin, glucose calcium and
phosphorus concentrations were determined in
plasma. The results indicated that offspring
number and weight of litter size at birth were
significantly (P<0.05) increased in the urea
groups compared to control group. Percentage of
good quality oocytes was high (70%) in control
group compared to 3% urea group (60%). Dietary 3%
urea was delayed cleavages to four-cell stage
embryos at the expected time. Dietary urea was
significantly (P<0.05) increased concentrations of
hematocrit and hemoglobin in blood and urea, total
protein, globulin, glucose, potassium and
phosphorus in plasma. In conclusions, although 3%
dietary urea decreased oocytes quality and timing
expected of embryo cleavages to four cell stages,
it increased significantly (P<0.05) offspring
number and weight of litter size.
Keywords:
Urea, Germinal vesicle, Cleavages, Embryos
