Post-extension evaluation of semen motility
This was done as described by Ajala et al18 for
pawpaw juice extender. Briefly, the immediate
post-extension sperm cell progressive motility
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was assessed and recorded as zero hour motility
score in percentage (%). Subsequent motility
scores were done hourly for 6 hours. Each time,
the assessment of sperm cell motility always
started from D2 and continued in order to D7,
and lastly D1 (100% buffer).
The motility assessment was done quickly and
carefully to ensure little time-lag in assessing
other extended semen. The concentration of
motile sperm cells of the extended semen was
estimated for the most suitable extender using
the average pre-extension semen volume and
concentration with average post-extension
motility at 2 hours storage time, and the value
recorded.
Analysis of data
A descriptive analysis was performed by
calculating means of sperm cell motility with
results presented as mean ± standard error of
mean (SEM). Using SPSS 11 software, one
way ANOVA test, at 5% significant level, was
used to determine whether or not there were
significant differences between mean motility
scores of sperm cells between the three
comparable extenders at 2 and 3 hours after
semen extension; and between these storage
times (at room temperature) in the most superior
extender.
RESULTS
The semen characteristics of the white and black
bucks are as shown in Table 1 (a), (b), (c) and
(d). The average motility score of sperm cells of
the white buck was significantly higher
(p=0.0001) than that of the black buck, Table 1
(a and b). Semen colour which is an indication
of sperm cell concentration was consistently
milky-white for the white buck while it was
consistently watery for the black buck. This
indicated poor sperm cell concentration of the
black buck. This was supported by the mean
concentration of sperm cells of white buck
which was significantly higher (p = 0.0001) than
the black buck’s (Tables 1a and 1b).
However, there was no statistical difference (p =
0.321) between the live scores (%) of sperm
cells of both bucks. The percentage of abnormal
sperm cells in the white buck, in contrast to the
black buck’s, was less than 20% recommended
by Zemjanis19 (Tables 1c and 1d).
pH of buffer
The pH of 2.5% sodium citrate in the 8 trials
ranged from 8.5 to 9.0 with an average value of
8.7 ± 0.9.
Values of coconut milk
The volumes of coconut milk obtained in the 8
trials ranged from 9 ml to 24 ml with a mean
value of 20.8 ± 1.4 ml. The pH of coconut milk
ranged from 5.8 to 6.1 with an average value of
6.0 ± 0.3. The relative amounts of constituents
of each extender and mean pH are as shown in
Table 2.
Parameters of semen prior to extension
Evaluation of the undiluted semen before
extension in the 8 trials is as shown in Table 3.
Post-extension motility scores of semen
The values presented here are those of the 5
trials used in the statistical analyses for up to 3
hours post-extension (p.e.) of semen. They are
shown in Table 4(a and b) for 2 and 3 hours p.e.
respectively, at room temperature. In all the 8
trials, the motility scores observed dropped to
virtually zero value by 4 hours p.e. The results
of the 4 hours and above are not shown. The
motility scores at 2 hours after extension in D2
were generally higher than in D3 and D4 in all
the trials, except in trial 5. It was also observed
that D3 was not different (p = 0.444) from D4 in
preserving semen motility at 2 hours p.e.
The motility scores at 3 hours after extension
followed the same pattern of decreasing motility
scores from extenders D2 to D4 as observed at 2
hours p.e. (Tables 4a and 4b). No statistical
difference (p = 0.693) was observed when mean
sperm cell motility at 2 and 3 hours p.e. were
compared for D2. In addition, mean motility
scores of semen in D2 at 3 hours p.e. was not
different (p = 0.106) from that in D3 at 2 hours
p.e. Using 52.6% mean sperm cell motility in
0.6 ml extended semen after 2 hours, we
estimated concentration of motile sperm cells in
D2 as 161.5 x 106 sperm cells (i.e. 269.2 million
sperm cells per