ابراهیم ستوده

We investigated the effects of soybean phosphatidylcholine (PtCho) on the growth, fatty acid (FA) profile, and body composition of juvenile Caspian brown trout. Juvenile trout, initial average weight 0.8 ± 0.12 g, were fed semi-purified formulated diets supplemented with 2, 4, and 6% PtCho for 5 weeks. Results showed that fish with diets containing 4 or 6% PtCho had significantly greater growth. The FA profiles of both the polar lipids (PL) and neutral lipids (NL) in juvenile tissues were influenced by dietary FA, although the effects of PtCho supplementation were more marked for PL than for NL. Fish fed PtCho in the diet also had higher levels of 18:2n-6, 20:4n-6 and n-6, and significantly lower levels of docosahexaenoic acid and eicosapentaenoic acid in both PL and NL. The lipid contents of whole-body tissues and liver were positively affected by PtCho percentage in the diet. Specific growth rate, hepatosomatic index, visceralsomatic index, and protein efficiency ratio were also significantly influenced by dietary PtCho. The results of our study indicate that dietary PtCho has a growth-promoting effect and that juvenile Caspian brown trout have a relatively moderate PtCho requirement (at least 4% dry weight of the diet).