International Journal of Aquaculture, 2013, Vol.3, No.22, 126
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Table 1 Main fatty acid composition (% of total fatty acids) of catfish larvae fed on three experimental diets
Fatty acid
Catfish larvae fed on experimental diets
Artemia
+Cyclopoids
Cyclopoids
Artemia
14:0
0.72
± 0.02
0.63
± 0.03
0.59
± 0.0
Iso15:0
0.48
± 0.03
0.59
± 0.01
0.37
± 0.03
15:0
0.86
± 0.01
0.82
± 0.02
0.80
± 0.16
16:0
19.30
± 0.31
20.36
± 0.04
18.39
± 0.73
Iso 17:0
0.39
± 0.02
0.34
± 0.04
N.D
17:0
1.15
± 0.06
1.54
± 0.02
0.92
± 0.04
18:0
13.68
± 0.11
15.54
± 0.03
14.11
± 0.45
∑SFAs
36.59
± 0.55
39.83
± 0.19
35.18
± 1.41
16:1
n7
0.59
± 0.01
0.36
± 0.06
0.48
± 0.06
16:1
n5
3.44
± 0.09
0.66
± 0.02
3.35
± 0.08
16:1
n4
1.02
± 0.02
0.91
± 0.06
0.88
± 0.05
18:1
n9
11.55
± 0.15
8.39
± 0.12
11.49
± 0.05
18:1
n7
4.97
± 0.01
2.24
± 0.04
5.10
± 0.05
∑MUFAs
21.57
± 0.28
12.55
± 0.31
21.30
± 0.3
18:2
n6 (LA)
6.73
± 0.09
5.37
± 0.03
6.50
± 0.37
18:3
n3 (LNA)
2.11
± 0.07
1.62
± 0.01
1.45
± 0.19
20:2
n6
1.06
± 0.0
1.28
± 0.0
1.13
± 0.05
20:3
n6
2.11
± 0.13
2.36
± 0.01
1.98
± 0.15
20:4
n6 (AA)
6.24
± 0.01
7.19
± 0.13
6.20
± 0.37
20:5
n3 (EPA)
4.29
± 0.18
2.80
± 0.08
3.71
± 0.01
22:5
n6
1.17
± 0.0
1.87
± 0.04
0.93
± 0.14
22:5
n3
1.29
± 0.10
1.18
± 0.03
1.36
± 0.02
22:6
n3 (DHA)
15.96
± 0.33
22.15
± 0.05
14.58
± 0.86
∑PUFAs
40.95
± 0.91
45.83
± 0.38
37.85
± 2.14
DHA/EPA
3.70
7.90
3.90
AA/EPA
1.50
1.60
1.70
DHA/AA
2.60
3.10
2.40
Note: N.D: Not Detected; ∑SFAs: Sum of Saturated Fatty Acids; ∑MUFAs: Sum of Monounsaturated Fatty Acids; ∑PUFAs: Sum of
Polyunsaturated Fatty Acids; DHA: Docosahexaenoic Acid; EPA: Eicosapentaenoic Acid; AA: Arachidonic Acid; LA: Linoleic Acid;
LNA: Linolenic acid
P=0.014), Linolenic acid (LNA, 18:3n3; F=14.7,
P=0.028) and Eicosapentaenoic acid (EPA, 20:5n3;
F=96.3, P=0.002), and higher composition of all
the five essential fatty acids when compared to
Artemia
only-fed larvae.
Figure 2 Impact of starter diet on essential fatty acid
composition of African catfish larvae
Note: Percentage composition of essential fatty acids of African
catfish larvae fed on three experimental diets (a mixture of
Cyclopoid copepods and
Artemia
,
Cyclopoid copepods and
Artemia
)
2
Discussion
The superior growth performance of catfish larvae fed
on a combination of Cyclopoid copepods and
Artemia
agrees well with previous studies that proved that
inclusion of copepods in the early fish larval diets
significantly improved survival and growth of fish
larvae (Molejo and Alvarez-Lajonch
è
re, 2003). This
improvement in growth can be attributed to the
nutritional base of Cyclopoid copepods as reflected in
fatty acid profiles of catfish larvae fed on Cyclopoid
copepods and a combination of Cyclopoid copepods
and
Artemia
as when compared to the case of
Artemia
only fed larvae. According to Wetzel (1999), fatty acid
composition of fish tissue is a consequence of the type
of dietary lipid ingested and the ability of a given fish
species to modify dietary lipids.