International Journal of Aquaculture, 2015, Vol.5, No.29 1
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5
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Figure 1 Linear relationship between Sperm count and % sperm
motility of
C. gariepinus
Figure 2 Testicular description of male
C. gariepinus
A sperm count varying from 3.8 x 10
10
spm/ml to 9.7
x 10
10
spm/ml was observed in the experimental fish.
Leung and Jamieson (1991) stated that spermatozoa
concentrations in fish may range from 2 x 10
6
to
5.3 x 10
10
.
Sperm count varying between 2.6 x 10
10
spm/ml to 3.5
x 10
10
spm/ml were observed in six species of carps by
Verma et al.,
(2009), variation of this from those
gotten in the experiment could be attributed to
difference in genera and species involved. McAndrew
et al
.,
(1993) stated that studies on the composition of
milt suggest large intra-specific and inter specific
variations in spermatozoa concentration and fitness
and seminal plasma composition. These variations
have been attributed to genetic variability, intratesticular
aging of spermatozoa, seasonality (Munkittrick and
Moccia 1987), breeding state and strategy (McAndrew
et al
.
1993.)
The sperm count observed in the present study where
higher than those in treated groups with
K africana
(6.5 x
10
9
spm/ml) as reported by Eunice et al., (2010). The
fairly high proportion of sperm count observed in this
experiment could be attributed to the fact that this
experiment was carried out at the peak of the breeding
season. This is in line with the report of Terner (1986)
that motility of the spermatozoa is observed at the
peak of the breeding season. Buyukhatipoglu and Holtz
(1984) and Munkittrick and Moccia (1987), reported
that sperm density decline as the season advanced,
whereas Rideout et al., (2004) and Piironen and
Hyvarinen (1983), noted that the spermatocrit and
sperm concentration increased over the stripping
season.
Verma et al.,
(2009) reported a progressive motility of
sperm of more than 60% in spermatozoa of Indian major
carps as well as in silver and grass carps. Studies on
brown trout (
Salmo truuta
) and Atlantic salmon (
Salmon
solar
) (Hajirezaee et al., 2010 and Vladic, 2011) have
shown that duration of motility and proportion of active
spermatozoa exhibit seasonal variation.
In rainbow trout, the proportion of spermatozoa that are
activated decreases as the spawning season progressed
(Buyukhatipoglu and Holtz 1984 Munkittrick and
Moccia 1987), this variation was attributed to decrease
as the spawning season progress in the concentration
and ratio of ions such as potassium and sodium which
are implicated in the initiation of sperm motility
(Munkittrick and Moccia 1987). Consequently increase
in the observed motility of studied fishes could be
attributed to possible increase in potassium and
sodium ion as the season peaks. More so, Eunice
(2010) showed a strong relationship between motility
and fertility as an increased motility resulted into
increased fertility. Rurangwa et al., (2001) also
observed a high correlation between sperm fertility
and spermatozoa motility and stated that higher
percentage of motile sperm is significantly correlated
to fertilization capacity in catfish,
Clarias gariepinus
,
hence it is concluded that higher motility observed in
this study means broodstock will exhibit high fertility.
This study however observed that body weight and
testes weight do not affect or influence the motility or
viability of the sperm as the regression analysis for
these parameters were not significant (P = 0.625 and P
= 0.498 respectively). This can be attributed to weight
gain being a function of food intake while sexual
