Comparing the Effects of Feeding a Fish Oil- or a Cod Liver Oil -Based Diet on Growth, Feed Utilization and Muscle Fatty Acid Composition Nile Tilapia (Oreochromis niloticus)

The present study was performed to investigate the influence of fish oil  (FO) and cod liver oil (CLO) as the dietary lipid sources on the growth performance, feed utilization and fatty acid (FA) composition of  Oreochromis niloticus . two isonitrogenous (38% crude protein), isocaloric (18.9 MJ GE/kg) diets containing 6% of added fat from the lipid sources were formulated and used. Each diet was fed to triplicate groups of 17 fish of 18.18 ± 0.02 g mean initial body weight fed with %3 body weight two times a daily. The tilapia was raised at          28±1 °C in 6 square experimental cages (1×1×1.25 m) during the 60 days. Results showed that the source of added lipid significantly influence ( P 0.05). In fish fed FO diet group, both  n −3 and  n −6 PUFA were the highest when compared with fish fed with CLO diet. The lipid source not influenced ( P <0.05) hepatosomatic index (HSI) and viscerosomatic index (VSI). However, fish fed CLO contained diet showed significantly higher liver fat (20.20±0.22) than fish fed FO diet group (13.88±0.22) ( P <0.001).