International Journal of Aquaculture, 2015, Vol.5, No.29 1
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5
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Table 1 Sperm quality parameters, weight and description of testes used
S/No. Wt. of Male
Fish (g)
Wt. of
Testes (g)
GSI
Testicular Description
Vol.
of
Semen
(ml)
Total Sperm
Count
(Sperm/ml)
Motility
%
Full
Semi-
full
Flat
Semi-
flat
Semen
Colour
1
420.9
2.42
0.575
X
Milky
0.70
6.50 x10
10
81.5
2
480.0
1.28
0.267
X
Milky
0.30
3.50 x10
10
57.1
3
496.6
0.97
0.195
X
Milky
0.20
6.00 x10
10
86.7
4
521.8
1.92
0.368
X
Milky
0.45
8.10 x10
10
88.9
5
621.1
2.10
0.338
X
Milky
0.50
5.90 x10
10
89.8
6
639.8
3.88
0.606
X
Milky
1.30
9.70 x10
10
93.5
7
527.1
1.10
0.209
X
Milky
0.25
5.00 x10
10
78.0
8
512.7
1.50
0.293
X
Milky
0.35
7.90 x10
10
93.7
9
601.1
3.00
0.499
X
Milky
1.00
8.80 x10
10
78.4
10
528.0
2.90
0.549
X
Milky
0.80
8.20 x10
10
87.8
11
495.5
1.20
0.242
X
Milky
0.30
9.10 x10
10
68.1
12
465.5
0.90
0.193
X
Milky
0.20
4.50 x10
10
84.4
13
600.0
2.90
0.483
X
Milky
0.80
–
–
14
611.9
3.20
0.523
X
Milky
1.10
7.5 x 10
10
80.0
15
556.6
2.80
0.503
X
Milky
0.70
–
–
Table 2 Correlation matrix between the sperm quality indices determined for
C. gariepinus
Wt. of Male
Wt. of Testes
Vol. of Semen
Sperm Count
% Motility
Wt. of Male
Wt. of Testes
0.684**
Vol. of Semen
0.679**
0.978***
Sperm Count
0.052
0.104
0.212
% Motility
-0.138
-0.190
-0.087
0.845***
** P<0.01
*** P<0.001
Equations: Multiple Regression equations of semen, gonad and somatic parameters of
C. gariepinus
Vol of Semen = - 0.219 + 0.000102 Wt_of_Male + 0.356 Wt_of_Testes (Equation 1)
r
2
= 95.7% (Adjusted = 94.9%), P = 0.000
% Motility = 39.0 + 7.4 Vol of Semen + 9 x10
-10
Sperm_Count - 11.6 Wt_of_Testes (Equation 2)
r
2
= 79.2% (Adjusted = 73.5%), P = 0.000
Figure 1 shows the linear regression graph for prediction
of % sperm motility from sperm count. This shows
that 71.4% of variance in sperm motility is accounted
for by variance in sperm count. This regression is the
only simple linear regression that was significant (P =
0.000).
Figure 2 shows the testicular description statistics for
the samples investigated. Most of the samples had full
testes while very few had semi-flat testes.
Discussion
Milt quality evaluation is critical to determination of
milt quality. The milt volume of the experimental fishes
ranged from 0.2 ml to 1.3 ml. Eunice et al
.,
(2010)
reported a milt volume between 1.1 ml and 2.0 ml for
Clarias gariepinus
fed different levels of
Kigelia
africana
(Medicinal plant), the difference in these
results is attributable to different experimental diets
used. Canyurt and Akhan, (2008) support this claim as
they stated that fish sperm quality is highly variable
and depends on various external factors such as
feeding regime, the quality of feed etc.
K. africana
fruit extracts had been used successfully as fertility
enhancing agent in rats (Abioye et al., 2003) and
possess promising pro-fertility quality (Eunice et al
.,
2010) hence could be said to have influenced the milt
volume. However the wide variance in milt volume
noticed between experimental feed can be linked to
genetic variability among the broodstock (Munkittrick
and Moccia 1987 and McAndrew et al.,
1993).
