International Journal of Aquaculture 2015, Vol.5, No. 41, 1-20
5
the sample was dried to constant weight, cooled for
ten (10) minutes in a desiccator each time before
weighing. Dried portion was subsequently used for the
determinations of protein, ash, fat and crude fibre.
Nitrogen determination for crude protein estimation
was done by by micro Kjeldahl method, while fat
was estimated using soxhlet extraction. Crude fibre
was measured by Trichoriacetic Acid Method of
Zarrow and Shay (1945). The residue from the moisture
determination in the muffle furnace was charred
between 500°C- 600°C for 12hrs until the ash is grey
or nearly white. Sample was allowed to cool and
weight taken. Model 6200 microprocessor-controlled
isoperibol oxygen bomb calorimeter was used for the
calorific tests (AOAC, 2006).
Triplicate sample of feeds were also analyzed using
flame atomic absorption spectrophotometer model
Buck 205, Buck Scientific, USA., while phosphorus
(P) was estimated spectrophotometrically using
molybdovanadate method (AOAC 1990).
Table 6 Effect of soya bean (full fat) and phytase on growth performance of juvenile
Clarias gariepinus
Sources of
variation, P value
Mean weight
gain (g/fish)
Daily weight
gain
(g/fish/day)
Daily feed intake
(g/fish)
FCR
Specific
growth rate
(%)
Survival rate
(%)
Phytase
0.007
0.00
0.771
0.00
0.079
0.000
Soya bean
0.000
0.000
0.000
0.000
0.00
0.000
Phytase* Soya bean 0.001
0.095
0.183
0.00
0.094
0.000
Pooled SE
0.483
0.008
0.072
0.058
0.031
0.604
Tukey HSD(means,
P values) Phytase
P0 vs P1
-1.05, 0.952 -0.07*, 0.037 -0.173, 0.934
2.23*, 0.000 -0.16, 0.448 5.96*, 0.031
P0 vs P2
4.74*, 0.032 0.05, 0.224
0.127, 0.978
2.20*, 0.000 0.06, 0.961
5.96*, 0.031
P0 vs P3
1.25, 0.914
0.0015, 1.000 -0.08, 0.997
2.07*, 0.000 0.03, 0.997
7.41*, 0.05
P0 vs P4
3.80, 0.114
0.029, 0.735 -0.09, 0.994
1.97*, 0.000 -0.05, 0.987 12.84*, 0.000
P1 vs P2
5.80*, 0.010 0.125*, 0.000 -1.86*, 0.000
-0.43, 0.186 0.23, 0.198
0.00, 1.000
P1 vs P3
2.31, 0.590
0.075*, 0.046 0.300, 0.705
-0.57*, 0.048 0.20, 0.331
1.44, 0.945
P1 vs P4
4.86, 0.038
0.103*, 0.004 0.08, 0.996
-0.66*, 0.016 0.12, 0.777
6.87*, 0.016
P2 vs P3
-3.49, 0.207 -0.05, 0.295 -0.20, 0.905
-0.13, 0.958 -0.03, 0.997 1.44, 0.945
P2 vs P4
-0.943, 0.973 -0.023, 0.892 -0.22*, 0.885
-0.23, 0.737 -0.11, 0.803 6.87*, 0.016
P3 vs P4
2.55, 0.496
0.028, 0.801 -0.01, 1.000
-0.10, 0.984 -0.08, 0.933 5.43, 0.076
Soya bean S0 vs S1 6.93, 0.063
0.12*, 0.035 -0.06, 1.000
-0.14, 0.988 0.17, 0.797
-5.00, 0.485
S0 vs S2
10.32*, 0.003 0.11, 0.064
0.05, 1.000
-0.06, 1.000 0.17, 0.807
-1.54, 0.986
S0 vs S3
16.55*, 0.000 0.23*, 0.000 -0.40, 0.799
-0.60, 0.275 0.38, 0.139
-3.84, 0.713
S0 vs S4
39.67*, 0.000 0.495*, 0.00 -1.13*, 0.038
-5.49*, 0.000 1.26*, 0.000 15.12*, 0.001
S1 vs S2
3.38, 0.151
-0.01, 0.987 0.11, 0.983
0.08, 0.987
-0.003, 1.000 3.46, 0.310
S1 vs S3
9.61*, 0.000 0.11*, 0.001
-0.34, 0.502
-0.46, 0.085 0.21, 0.175 1.15, 0.963
S1 vs S4
32.73*, 0.000 0.37*, 0.000
-1.07*, 0.000
-5.35*, 0.000 1.08*, 0.000 20.11, 0.000
S2 vs S3
6.23*, 0.002 0.1*2, 0.000 -0.45, 0.236
-0.54*, 0.031 0.21, 0.165
-2.31, 0.683
S2 vs S4
29.35*, 0.000 0.39*, 0.000 -1.18, 0.000
-5.43*, 0.000 1.09, 0.000
16.65, 0.000
S3 vs S4
23.12*, 0.000 0.27*, 0.000 -0.73*, 0.018
-4.89, 0.000 0.87, 0.000
18.96, 0.000
Note: *Mean differences are significant at P<0.05
2.4 Analysis of antinutrients
Phytate, tannin, and oxalate composition of raw,
processed and experimental diets were determined in
duplicate samples as follows.
2.4.1 Phytate
Phytate in feed samples was measured by alkaline
picrate method of Oberleas (1973). Sample was
extracted with 0.2N HCl to give (3-30µg ml-1 phytate
solution). 0.5ml of extract was pipetted into a test tube
fitted with a ground glass stopper. 1ml of ferric
solution was added to the tube, which was covered
with the stopper and fixed with a clip. The tube was
heated in a boiling water bath for 30 minutes. Care
was taken to ensure that for the first 5 minutes, the
