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Growth, fat content and fatty acid profile of South American catfish, surubim ( Pseudoplatystoma fasciatum ) juveniles fed live, commercial and formulated diets
Author(s) -
Arslan M.,
Dabrowski K.,
Portella M. C.
Publication year - 2009
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/j.1439-0426.2008.01154.x
Subject(s) - catfish , biology , tubifex , phospholipid , fatty acid , zoology , cannibalism , food science , essential fatty acid , polyunsaturated fatty acid , biochemistry , fishery , ecology , fish <actinopterygii> , larva , membrane
Summary South American catfish, barred surubim ( Pseudoplatystoma fasciatum ) juveniles (117.6 ± 11.8 mg individual weight; 28.3 ± 2.5 mm total length) were fed various diets: one live ( Tubifex worms), two commercial (Aglo Norse and Bio Kyowa), and one semi‐purified formulated diet (75% peptide based protein) over a 2‐week period. Fish fed the Aglo Norse diet showed the highest growth performance, but cannibalism also was very high (42%). Fish fed peptide based formulated diet demonstrated the lowest growth rate, with no cannibalism. The highest survival was achieved with fish fed Tubifex worms (100%). Lipid level in the whole body of the fish fed four different experimental diets did not differ significantly, averaging 3.6 ± 0.7%. Fatty acid composition of neutral and phospholipid fractions of whole body lipids of fish reflected the fatty acid composition of the diets. The high level of 20:4 n ‐6 in Tubifex worms resulted in a high level of this fatty acid in the tissue of fish fed this diet. It remains uncertain how high survival and no cannibalism is related to dietary lipids/fatty acids. In all cases, the increasing ratio of n ‐3 HUFA (highly unsaturated fatty acids)/ n ‐6 HUFA in phospholipid fractions suggested the elongation and desaturation of 18:3 n ‐3 to 22:6 n ‐3 via 20:5 n ‐3. Moreover, in respect to the 20:4 n ‐6 levels in the diets, an increase in the concentration of this fatty acid in phospholipid fraction suggests that South American catfish can transform linoleate into arachidonate.