International Journal of Aquaculture, 2017, Vol.7, No.10, 71-78
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microfuge (Tarsons, India) at 2500 ×g for 10 min. The serum samples of five fish from each of the three replicate
were pooled separately (0.5-1.0 ml serum/tube), labelled and stored in a deep freezer (Blue Star India, Ltd) at
-20ºC until use.
Table 1 Culture and management practices followed in normal and sewage-fed farms
Normal pond
Sewage-fed pond
Location
Lat. 22
o
29’N; Long. 88
o
29’E
Lat. 22
o
82’N; Long. 88
o
20’E
Area of the farm (ha)
0.93
40.00
Area of the experimental pond (ha)
0.33
18.67
Water depth (m)
1.90
1.20
Type of pond
Perennial
Perennial
Application of Dolomite (kg/ha/year)
Nil
75
Mahua oil cake (kg/ha/year)
150
525
Lime (kg/ha/year)
75
265-420
Type of culture
Polyculture
Polyculture
Species cultured*
Catla catla,
Labeo rohita,
Cirrhinus mrigala,
Cyprinus carpio,
Ctenopharyngodon idella,
Oreochromis niloticus,
Aristichthys nobilis,
Macrobrachium rosengergii
C. catla,
L. rohita,
C. mrigala,
L. bata,
C. carpio,
Hypophthalmichthys molitrix,
C. idella,
O. niloticus,
O. mossambicus, Mylopharyngodon piceus
A. nobilis
Stocking (Fingerlings/ha)
15,000
20,000
Staggered stocking
No
Yes
Harvesting
a
Multiple
Multiple
Water source
Rain water and surface runoff
Rain water, surface runoff and metropolitan
city sewage**
Note: *: No stocking ratio was maintained in both farms; **: Source: Intake of Kolkata metropolitan city sewage, tannery effluent
and other waste water on every 3 days interval from the network of drainage channel; a: On attaining a size of 250-500 g.
The serum IGF-1 was determined by the fish IGF-1 ELISA kit (Catalogue Number: MBS700712; MyBiosource,
San
Diego,
CA)
as
per
the
manufacturer’s
instructions
(
.). In brief, 50 µl each of
the test serum or standard was taken in wells in triplicate for each sample. To which added was 50 µl of
HRP-conjugate, mixed well and incubated for one hour at 37°C. The blank well was also set without any solution
and HRP-conjugate. The contents of the wells were aspirated and washed. The process was repeated two times for
a total of three washes. Washing was done by filling each well with 200 µl wash buffer using a squirt bottle and
let it stand for 10 sec. After the last wash, any remaining wash buffer was removed by decanting. The plate was
inverted and blotted it against clean paper towels. Then 50 µl each of substrate A and substrate B were added to
each well, mixed well and incubated for 15 min at 37°C. Finally, 50 µl of stop solution was added to each well
and gently tapped the plate to ensure thorough mixing. The optical density of each well was measured within 10
min using a visible microplate reader (HALO-MPR-96, Dynamica, Australia) set to 450 nm.
2.5 Statistical analysis
One-way analysis of variance (ANOVA) and Tukey’s comparison of means was used to test the significance of
differences, at probability levels of 0.05, among the fish species and treatment groups. Statistical analyses were
performed using SPSS 16.0 for Windows software (SPSS Inc., Chicago, IL, USA).
