International Journal of Aquaculture, 2017, Vol.7, No.16, 106-110
108
(i) Survival Rate =
oRoma
ݐ
t浔 Rt t ੪ 䘥 R浔oma oo
oRoma
ݐ
t浔 Rt t ੪
tt
The different variables measured across the treatment were obtained using Minitab 14 for windows software.
Result was then subjected to Analysis of variance and where significant differences occurred; means were
separated using Fisher’s least significant difference.
3 Results
The result of water quality parameters in the culture unit used for the experiment (Table 1) revealed that no
significant difference (P>0.05) were obtained between parameter measured for the rearing tanks for all male
tilapia and that of the mixed tilapia. The pH varied from 7.2 in all male to 7.3 in mixed sex. Temperature and total
dissolved solid were 27.4°C and 64.82 mg/L respectively in all male tilapia and 27.7°C and 65 mg/L respectively
in mixed-sex tilapia. Conductivity recorded was 93.05 and 92.99 in all male and mixed sex tilapia respectively.
Table 1 Water quality of culture units for all male and mixed-sex
Oreochromis niloticus
Parameters
All male
Mixed-sex
P-Value
pH
7.2 + 0.54
7.3 + 0.23
0.081
Temperature
27.4 + 0.92
27.70 + 0.09
0.827
TDS
64.82 + 0.25
65.00 + 1.04
0.223
Conductivity
93.05 + 1.21
92.99 + 2.21
0.412
Note: Mean in the same row do not differ significantly (P ≤ 0.05)
The result for growth parameter as summarized in Table 2 revealed final weight of all male tilapia to be
significantly higher (5.94 ± 0.13 g) than mixed sex (2.20 ± 0.09 g) (P ≤ 0.05). Similarly, weight gain was higher in
all male fish (5.93 ± 0.13 g) as against (2.19 ± 0.09 g) recorded for mixed-sex. Also, Figure 1 shows the biweekly
growth pattern of all male and mixed-sex
O. niloticus
during the study period. The same trend was observed for
growth rate, specific growth rate, feed fed, feed conversion efficiency and protein efficiency ratio with higher
values recorded for all male tilapia fish (0.035 ± 0.001, 3.94 ± 0.02, 16.24 ± 0.03, 36.50 ± 0.75 and 0.198 ± 0.01
respectively) compared to the mixed sex tilapia (0.013 ± 0.001, 3.29 ± 0.001, 6.45 ± 0.15, 34.13 ± 2.22 and 0.073
± 0.01 respectively). However, feed conversion ratio was higher in the mixed-sexes (2.74 ± 0.06) than the all male
O. niloticus
(2.94 ± 0.19). The study observed no significant variation in survival of all male and mixed-sex fish
(P ≥ 0.05). No breeding activity was noticed in both groups under study.
Table 2 Growth Parameters and nutrient utilization of all male and mixed-sex
Oreochromis niloticus
Parameters
All male
Mixed sex
P-Value
MIW
0.008 ± 0.01
0.009 ± 0.07
0.231
FW
5.94 ± 0.13
a
2.20 ± 0.09
b
0.001
WG
5.93 ± 0.13
a
2.19 ± 0.09
b
0.023
MIL
2.42 ± 0.01
2.21 ± 0.07
0.231
FL
6.44 ± 0.13
a
5.20 ± 0.09
b
0.001
LG
4.93 ± 0.13
a
3.19 ± 0.09
b
0.023
GR
0.035 + 0.001
a
0.013 ±0.001
b
0.001
SGR
3.94 ± 0.02
a
3.29 ± 0.03
b
0.001
Feed Fed
16.24 ± 0.03
a
6.45 ± 0.15
a
0.000
FCR
2.74 ± 0.06
b
2.94 ± 0.19
a
0.001
FCE
36.50 ± 0.75
a
34.13 ± 2.22
b
0.001
PER
0.198 ± 0.01
a
0.073 ± 0.01
b
0.011
Survival
75.0 ± 0.00
75.0 ± 0.00
1.000
Note: Mean in the same row with different superscripts differ significantly (P ≤ 0.05). Key: MIW = mean initial weight; FW= Final
weight; WG=Weight gained; MIL= Mean initial length; FL= Final length; LG= Length gain; GR=growth rate; SGR=Specific growth
rate; FCR=Feed conversion ratio; FCE= Feed conversion efficiency; PER= Protein efficiency ratio
