International Journal of Aquaculture, 2013, Vol.3, No.6, 23
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respectively (Figure 4). There was significant differences
(
ANOVA, p<0.05) in growth rate among ponds, with
fish sampled from maize bran fed ponds having the
highest growth rate, followed by fish fed with chicken
manure pond and, the control pond had the least growth:
Specific Growth Rate: was significantly different (ANOVA,
p<0.05) among the three experimental ponds. The
specific growth rate of fish sampled from maize bran and
chicken manure fed ponds decreased significantly from
week 8 to week 24. However, the fish from maize bran
and chicken manure fed ponds showed considerably
higher specific growth rate than the control pond (Figure 5).
Condition factor: results for each pond are shown in
Figure 6. High condition factor value ranges were observed
in maize bran fed fish which had a mean condition factor
of (9.46±0.91) K, chicken manure (7.17±0.16) K and for
fish in the control pond it was with (3.88±0.16) K.
Condition factor difference were statistically significant
(
ANOVA, p<0.05) in fish sampled from all the ponds.
Figure 4 Percentage weight gain for the three experimental ponds
Figure 5 Specific growth rates for maize bran, chicken manure and
the control pond
Figure 6 Condition factor for the maize bran, chicken manure
and control fed fish
1.3
Survival rate
Survival was variable among ponds, but was not
significantly (ANOVA, p>0.05) different among pond
treatments and the fish in control pond had the
highest survival rate (90%) as shown in Table 1.
Table 1 Survival rate for the three ponds carried out in the
experiment
Pond
Number
Survival rate (%)
Maize bran
22
76.7
±12.3
Chicken manure
19
63.3
±9.6
Control
27
90.0
±4.9
2
Discussion
Total dissolved substances, electrical conductivity
and light penetration recorded during this study are
important ecological variables in aquaculture (Ellis
et al., 2002). Okpokwasiti and Obah (1991) reported
highly significant seasonal variations in total dissolved
solids, electrical conductivity and light penetration
of ponds, the same to what was done in this study.
Similar results were also reported by (Ahmad et al
.
, 2008)
who observed that planktonic biomass and fish
production depend highly on conductivity and total
dissolved solutes to maintain a high specific growth rate.
The light penetration varied significantly during this
experiment and the variations maybe attributed to
the different chemical constituents in the maize bran
and the chicken manure feeds which absorb
components of light differently when dissolved in
water. Water transparency was consistently higher in
the control pond which could be possibly due to low
or no phytoplankton production in the water because
there was no feed applied. Light penetration depends