International Journal of Aquaculture, 2013, Vol.3, No.16, 85
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91
http://ija.sophiapublisher.com
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Table 2 Concentrations of amylase in different fish species when fed on different feed ingredients (IU/min/mL)
Fish species
Rice polish
Soybean meal
Cotton seed meal
Catla catla
0.05
±0.003
aA
0.016
±0.001
bA
0.027
± 0.002
cA
Cirrhinus mrigala
0.054
±0.001
aB
0.054
±0.002
bB
0.034
±0.004
cB
Labeo rohita
0.05
±0.002
aA
0.015
±0.002
bA
0.019
±0.001
cC
Hypophthalmicthys molitrix
0.01
±0.0003
aC
0.009
±0.0001
bC
0.013
±0.003
aD
Note: Data figures with different lower case letters across the rows and upper case letters down the columns are significantly
different from each other at P<0.01
1.3
Lipases
Catla catla
showed the highest lipase activity when
fed on soybean meal while lipase activity was the
highest in
Cirrhinus mrigala
when fed on rice
polish. Lipase secretion levels were similar and
quite lower than its counterparts in
Hypophthalmichthys
molitrix
in all the ingredients fed (Table 3).
Catla
catla
secreted lowest concentrations when fed on
cotton seed meal while the second highest when fed
on rice polish.
Labeo rohita
did equally well in all
the ingredients but levels were quite higher than
Hypohthalmichthys molitrix
but lower than
Catla
catla
and
Cirrhinus mrigala
in some combinations
(
Table 3).
Table 3 Concentrations of lipase in different fish species when fed on different feed ingredients (IU·min
-1
·
mL
-1
)
Fish species
Rice polish
Soybean meal
Cotton seed meal
Catla catla
9.2
±2.5
aA
16.3
±3.5
bA
4.5
±1.5
cA
Cirrhinus mrigala
12.5
±3.2
aA
8.2
±3.1
bB
9.2
±2.6
bB
Labeo rohita
8.7
±2.7
aB
8.7
±3.4
aB
8.5
±2.1
aB
Hypophthalmicthys molitrix
3.5
±1.9
aC
3.7
±1.3
aC
3.5
±1.5
aC
Note: Data figures with different lower case letters across the rows and upper case letters down the columns are significantly
different from each other at P<0.01
1.4
Proteases
Though proteases also varied from species to species
and from ingredient to ingredient but variations were
less prominent as have been observed in former
enzymes. Proteases showed higher activities in all the
fish species except
Hypophthalmichthys molitrix
which elicited poor secretions. Level of proteases
was same in all the ingredients when fed to
Hypophthalmichthys molitrix
and significantly lower
than its counterparts in the same treatment groups. Its
protease levels were comparable to
Cirrhinus
mrigala
when fed on soybean meal and to that of
Catla catla
when it was fed on cotton seed meal
(
Table 4).
Table 4 Concentrations of protease in different fish species when fed on different feed ingredients (IU·min
-1
·
mL
-1
)
Fish species
Rice polish
Soybean meal
Cotton seed meal
Catla catla
4.2
±0.5
aA
4.2
±0.5
aA
3.4
±0.3
bA
Cirrhinus mrigala
4.2
±0.3
aA
3.2
±0.3
bB
4.4
±0.4
aB
Labeo rohita
4.2
±0.5
aA
3.7
±0.2
bB
3.98
±0.3
aB
Hypophthalmicthys molitrix
3.2
±0.4
aB
3.1
±0.3
aC
3.4
±0.2
aA
Note: Data figures with different lower case letters across the rows and upper case letters down the columns are significantly
different from each other at P<0.01
1.5
Water Quality Parameters
Due to daily exchange of water all the physico-chemical
parameters remained within the acceptable range
(
Table 5).
2
Discussion
Growth and survival data are powerful tools for understanding
the effects of quality of feed on growth and linked
metabolic mechanisms in fish (Wang et al., 2005). Our
findings favorably fit in and support this statement
because we observed the highest and uniform growth
in all the fish species when fed on rice polish. Change
in species and type of feed significantly affected the
fish growth which was very much evident when
Catla