IMPROVEMENT OF THE NUTRITIONAL VALUE OF NILE TILAPIA USING FINISHER DIETS.

The wash out strategy using fish oil based diet before harvest affords the saving of feed costs and high fillet quality for human nutrition.  The optimal duration for the inclusion of fish oil in tilapia diet should be determined to guarantee improvement of tilapia fillet by decreasing the content of ω6, especially linoleic acid (LA) which is critical for economical and sustainable benefits.

This study was designed to examine the suitable duration for washing out ω-6  prior early harvest of tilapia fish when the average harvest weight  ranged between 100-150 g.  Two different lipid sources soy oil (SO) and fish oil (FO) were used to generate three different feeding regime; SO diet continuously for 6 weeks, FO diet continuously for 6 weeks, and SO diet for 3-wk followed by FO diet for 3-wk (SO/FO treatment). Growth performances of Nile tilapia fed on FO-finishing diet continuously did not have significant improvement in growth performance or feed utilization compared with tilapia fed SO diets and those subjected to SO/FO treatment. Tilapia fed SO diet continuously for 6 weeks had the highest significant LA (39.6) and ARA (2.03) in the fillet. While the lowest values were recorded for fish fed FO-finishing diet for 6 weeks. The decrease in fillet content of such fatty acid is consider beneficial for human consumer. High level of Ѡ6 is a precursor for inflammation and tumor diseases. Tilapia direct that much of fatty acids in viscera sector, therefore the tilapia by products included the Viscera could be considered as functional ingredient and could be used as lipid source in aqua-feed manufacturing.