Freshwater fish are an important source of protein, but they also contain other highly nutritive components such as fats. Polyunsaturated fatty acids (PUFAs) are essential for normal growth, development and reproduction of vertebrates. The antioxidant role of vitamin E in cell membranes prevents fatty acid and cholesterol oxidation, thereby promoting PUFA and subcellular particle stabilization. The effects of vitamin E supplementation on the quality of Nile tilapia (Oreochromis niloticus) carcass were investigated. The experiments were carried out in an experimental laboratory over 106 d. After sex reversal, 400 early juvenile O. niloticus were tested in a completely randomized experiment with 5 treatments (4 repetitions each), consisting of vitamin E monophosphate supplementation at 0, 50, 100, 150 or 200 mg/kg of a base diet. Treatment diets contained equal amounts of protein and energy. Tilapias supplemented with vitamin E contained arachidonic acid (20:4 x-6; AA) which participates in inflammatory response. Nile tilapia carcasses that received vitamin E at 100 and 150 mg/kg diet had improved carcass quality by increasing the PUFA:SFA ratio and had the highest levels of polyunsaturated fatty acids from the omega-3 (linolenic acid; 18:3 x-3) and omega-6 (linoleic acid; 18:2 x-6) series.

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This study aims to evaluate the effect of different initial densities of Nile tilapia fingerlings on water quality, fish growth, and production of marjoram (Origanum majorana L.) and sweet basil (Ocimum basilicum L.) in a recirculating aquaponic set up. The experiment was carried out on randomized block design and comprised four fish densities (0, 150, 250 and 500 fish m-3) and two crops, in which each treatment was continued for 45 days and replicated three times. Except for pH and total alkalinity, all water physicochemical parameters were increased significantly at high fish densities. In contrast, most of the biological parameters for fish were unaffected by culture density, although at the highest density crude protein percentage was significantly increased and ether extract percentage was significantly reduced. Plant productivities were highest when fish were cultured at density of 500 fish m-3 , a density that was found to be appropriate for maintaining water quality and promoting fish growth while preventing toxicity and mortality. The present study has demonstrated the technical viability of coupling Nile tilapia culture coup with aquaponic production of marjoram and sweet basil.