Dietary effect of varying linseed oil compositions on growth response, survival and polyunsaturated fatty acid levels in Tilapia (Oreochromis niloticus)

The present study evaluated the impact of varying dietary linseed oil composition on growth, survival and tissue polyunsaturated fatty acids (PUFA) profiles in Nile tilapia (Oreochromis niloticus). Five iso-nitrogenious diets with varying linseed and sunflower oil concentrations were formulated and fish fed twice daily to for 3 months. Commercial diet was used as a control in triplicate tanks set for each diet treatment. Growth parameters were measured from changes in body weight and length. A 75:25 ratio of sunflower oil to linseed oil gave a better survival and specific growth rate than 100% linseed oil or 100% sunflower oil. Tissue PUFA composition were determined using gas chromatography. High dietary linseed oil composition (100%) resulted into significantly high (P 50% reduced growth and survival rate in tilapia, however, it increased tissue accumulation of essential fatty acids which also increased with the length of feeding period.   Key words: Growth, Tilapia, n3 fatty acids, linseed oil, polyunsaturated fatty acids (PUFA).