ABSTRACT
Bolti [Tilapia nilotica] fish and water samples were taken from three different locations in Kafr El-Sheikh governorate. Water quality and oil characteristics in fish flesh were studied. The obtained results showed that crude lipid and phospholipid contents of fish fillet were increased by increasing total solids and total hardness of fish environment. Peroxide, iodine and acid values of fish oil influenced by water quality. Fatty acids composition in fish oil showed a wide variation due to differences in water-head. Total unsaturated fatty acids in drainage fish oil were higher than that found in farm's fish oil, while the lowest percentage of unsaturated fatty acids was recorded by Nile's fish oil. Generally, palmitic was the main saturated fatty acid in fish oil, whereas it constituted about 66-68% of the total saturated fatty acids. Nile's fish oil contained higher amounts of omega-3 fatty acids than those of drainage and farm's fish oils. In contrast, odd and branched fatty acids content in drainage and farm's fish oils were higher than those found in Nile's fish oil. Concentrations of arachidonic and erucic acids in oil extracted from drainage fish were higher than oil extracted from farm's fish, while the lowest concentration for these fatty acids were found in oil extracted from Nile's fish. Although the acid value and peroxide value of drainage and farm's fish oils were slightly high, it is still accepted for human consumption according to The Association of Fish Meal Manufacturers