International Journal of Aquaculture, 2016, Vol.6, No.21, 1
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9
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3 Results
The water quality parameters monitored over the experimental period ranged as follows. Temperature: 28 to 29.5
ºC, pH: 7.4 to 8.4, dissolved oxygen: 5.0 to 8.8 ppm, free carbon dioxide: nil to 1.4 ppm and total alkalinity 42 to
70 ppm. The average plankton wet and dry weight values varied from 4.84 to 17.09 mg and 1.33 to 5.69 mg/100 L.
On termination of the experiment, the average fish weight recorded was 67.82 g (2 g G-Pro), 61.82 g (1 g G-Pro),
51.79 g (4 g G-Pro) 51.57 g (3 g G-Pro) and 49.46 g (Control) (Table 3). Weight gain in 2 g treatment was
significantly (P<0.05) higher from that of the rest of the treatments and the control, while that of 1 g treatment was
significantly higher than that of 3 and 4 g treatments as well as the control. The difference in growth of 3 g and 4
g G-Pro treated fish and the control was not significant (P>0.05). The highest specific growth rate and RNA: DNA
ratio was obtained in fish from 2 g treatment; they were the lowest in the control. HSI was highest in the control
(0.59) and lowest in 3 g treatment (0.38). VSI was higher in the treated fish; the highest and lowest values (18.18,
9.62) were recorded in 2 g treatment and the control respectively. Survival of fish was maximum at 86.0% under 2
g treatment as against the minimum 76.0% in the control. Net fish production was the highest in 2 g treatment.
The highest feed digestibility (dry matter 81.49%, protein 87.68%, fat 91.94%) was recorded under 2 g treatment,
whereas it was the lowest in the control (79.02%, 84.01% and 87.23% respectively). FCE was the best under 2 g
treatment (27.88%); it was the least under the control (25.26%).
Table 3 Growth parameters (±S.E.) of common carp fed experimental diets
Parameter
Diets
T
0
T
1
T
2
T
3
T
4
Final weight (g)
49.46 ±1.03
a
61.62 ±1.09
b
67.82 ±0.84
c
51.57 ±1.03
a
51.79 ±2.91
a
Final length (cm)
13.30 ±1.31
a
14.11 ±0.64
a
14.75 ±1.13a
13.90 ±0.70
a
13.70 ±0.59
a
Specific growth rate (%)
2.95 ±0.09
a
3.11 ±0.03
b
3.13 ±0.08
b
2.98 ±0.12
a
2.98 ±0.07
a
Food conversion efficiency (%)
25.26 ±0.46
a
27.06 ±0.12
b
27.88 ±0.51
b
27.70 ±0.18
b
25.84 ±0.21
a
RNA:DNA ratio
3.12
5.24
5.46
3.49
3.57
Survival (%)
76.0
84.0
86.0
84.0
78.0
Net production (g/25m
3
/140 days)
1879.48
2 588.04
2 916.26
2 165.94
2 019.81
HSI (%)
0.59 ±0.04
b
0.46 ±0.06
a
0.53 ±0.06
ab
0.38 ±0.02
a
0.42 ±0.02
a
VSI (%)
9.62 ±0.32
a
15.80 ±0.76
c
18.18 ±0.65
d
16.16 ±0.48
c
13.84 ±0.27
b
Carcass proximate composition (%)
Moisture
76.39 ±0.07
a
75.41 ±0.09
a
75.31 ±0.18
a
75.81 ±0.07
a
75.70 ±0.08
a
Protein
18.22 ±0.05
a
19.17 ±0.04
b
19.43 ±0.04
b
18.57 ±0.05
a
18.75 ±0.03
a
Lipid
1.95 ±0.02
a
2.43 ±0.04
b
2.43 ±0.08
b
2.28 ±0.06
b
2.32 ±0.05
b
Ash
1.58 ±0.03
d
1.33 ±0.02
b
1.09 ±0.03
a
1.47 ±0.01
c
1.52 ±0.01
d
Digestion coefficient (%)
Dry matter
79.02
80.50
81.49
79.49
79.88
Protein
84.01
86.60
87.68
84.90
85.08
Fat
87.23
90.16
91.94
88.44
88.89
Note: Values with different superscripts in the same row indicate significant (P≤0.05) difference
Carcass protein content was the highest in 2 g treatment (19.43%) as against the lowest of the control (18.22%).
Lipid content was significantly higher and similar in fish from 1 g and 2 g treatments (2.43%) compared to the
control (1.95%). Ash level was the lowest in 2 g G-Pro treated fish and the highest in the control (Table 3).
Pancreatic amylase activity was the highest in 4 g G-Pro treated fish (1.04 units); in contrast in the 1
st
intestinal
segment, its activity was highest in the control (2.36 units). In the 3
rd
segment, highest amylase activity was
recorded in 2 g G-Pro treated fish (1.23 units), while in the 2
nd
segment activity was higher in all the treated fish
(P<0.05). Compared to amylase and lipase activities, protease activity was higher in all the fish. Among the
treated fish, higher doses induced higher protease activity in the pancreas. However, in the intestinal segments, the
activity was higher with the lower doses. Lipase activity was higher in the pancreas of 1 g and 2 g G-Pro treated
fish. Intestinal segments of control fish showed better lipase activity (Table 4).
