The effect of different dietary fatty acid sources (Fish oil (PUFA), Soybean oil (06), linseed oil ( 3 )) on growth performance of Nile tilapia (Oreochromis niloticus) and body fatty acids composition was investigated. Tilapia fed diet containing 4.2 (6/ 03 ratio (3% soybean oil) had higher significant (P ≤ 0.05) differences in the fi- nal body weight, average body weight gain and specific growth rate than other treatments. Feed conversion ratio being better with diet content 4.2006/03 ratio (3% soybean oil) compared to other treatments. Body lipid content of tilapia fed diet content of 0.45; 1.2 and 4.6 dietary 06/03 ratio (5 % lipid level) had the highest significant (P ≤ 0.05) values than fish fed 0.6; 1.40 and 4.20 dietary @6/03 ratio (3% lipid level), irrespective of the dietary lipid sources.
The whole body (F.A.) 18: 109 concentration was higher in tilapia fed diet containing 0.45 06/ 03 ratio ( 5% linseed oil), whereas 18: 2006 was more concentrated in the whole body lipid of fish fed diet containing 4.20 and 4.6 06/03 ra- tios (3% and 5% soy bean oil respectively). The highest concentration of 18: 303 was found for fish fed 0.45 and /or 0.60 06/03 ratio ( 5% and 3% linseed oil), respectively. The results of total blood serum lipid followed the same tendency. The highest fish production (Kg / pond)( 8.32) and profits (L.E/ Pond) (26.98) were recorded for tilapia fed 4.2 06/03 ratio (5%soybean oil).
The results revealed that, among dietary sources of fatty acid, vegetable oils have certain advantages to fish oils. They are cheaper, available in large quantities and less subject to oxidation than non- hydrogenated fish oil. Moreover, they permit reasonable growth and feed conversion as the fish