128 JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 1, 2003 © 2003 Institute of Food Technologists Food Chemistry and Toxicology JFS: Food Chemistry and Toxicology Introduction B ECAUSE OF THE INCREASED DEMAND FOR SEAFOOD, THE aquaculture industry has been experiencing an expansion in the last few decades; in contrast traditional fishery is suffering from catch decline due to overfishing and habitat deterioration. Fish farming offers the possibility to control the quality of the entire production process and to obtain a final product with quality at- tributes as close as possible to those of wild fish. In intensive farm- ing, the diet composition and feeding regimen affect the chemical composition of fish muscle (Shearer 2001). In particular, its lipid profile may be modulated qualitatively and quantitatively, within certain limits, through the formulation of feeds with high levels of n-3 polyunsaturated fatty acids (PUFA), which are now known to be responsible of the health-promoting effects of marine lipids. Sea- food products are, in fact, the only significant source in the human diet of polyunsaturated fatty acids, in particular those of the n-3 family (eicosapentaenoic acid, 20:5 n-3; docosahexaenoic acid, 22:6 n-3); these are precursors of hormone-like substances with anti- thrombogenic and antiatherogenic properties, and they play a fun- damental role in the development of neural and visual functions. The health benefits associated with a diet rich in seafood products have been documented by several epidemiological and clinical studies in recent years (Kromhout and others 1985; Phillipson and others 1985; Herold and Kinsella 1986). Considering the primary role played by seafood in human health and the increasing consumption of fish in Italy (23 kg/person/year, ISMEA 2001), the nutritional characterization of fish species repre- sentative of the Italian aquaculture production, Sparus aurata and Dicentrarchus labrax, amounting together to about 20% of the total aquaculture production of fish, and their comparison with wild fish of the same species are of great importance. The nutritional characterization of aquaculture products repre- sents an important step toward a quality certification process of seafood that informs the consumer about the origin, handling practices, and processing history of the products, thus guarantee- ing safety requirements and nutritional properties. The objective of this study was to identify the elements of differ- entiation that characterize wild and farmed sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata), both euryhaline species widely produced and consumed in Italy. Materials and Methods Experimental design Market-sized wild and farmed seabass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) were harvested in different seasonal periods between 1998 and 2000. During this period, 4 samplings were performed for wild sea bass, and 6 for farmed sea bass. For gilthead sea bream, the samplings performed were 7 for wild, and 11 for farmed fish. Within each sampling, 3 to 4 pools, each composed of 4 fish selected at random, were analyzed separately in duplicate. Therefore, for each sampling, a total of 12 to 16 fish were analyzed. Fish growth conditions Wild fish, caught in 2 Italian lagoons (Orbetello, Central Tyrrhe- nian Sea, and Venice, Northern Adriatic Sea), included fish coming in from the sea and fish transferred as juveniles in the lagoons; the fish feed exclusively on the resources of the aquatic environment. During the experimental period, water temperature in the 2 la- goons fluctuated between 2 to 6 °C in winter and 26 to 28 °C in sum- mer, and water salinity within the range 30 to 45 g/L. Farmed fish of either species, caught contemporaneously to lagoon specimens of comparable body size, were obtained partly from rearing plants that collected water from the same lagoons and partly from farms located in different parts of Italy and collecting water from the sea or from groundwater. In this latter case, water temperature was constant throughout the year (about 20 °C), while in farms collecting water from the sea, water temperature fluctuated within the range 14 to 26 °C during the year. In all plants, fish were grown in tanks to a final stocking density of 20 to 40 kg/m 3 and fed twice a day with commercial pellet feed containing fish meal, fish oil, soybean meal, wheat meal, yeast, and vitamin and mineral supplements. Water in the tanks was oxygenated by liquid oxygen or mechanical aeration, depending on the farm, to provide an outlet dissolved oxygen con- centration of 4 to 7 ppm. Differentiation in the Lipid Quality of Wild and Farmed Seabass ( Dicentrarchus labrax ) and Gilthead Sea Bream ( Sparus aurata ) E. ORBAN, T. NEVIGATO, G. DI LENA, I. CASINI, AND A. MARZETTI ABSTRACT: The elements of differentiation that characterize the quality of the lipid fraction of wild and farmed sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) were investigated. Reared fish of either species had a total lipid content significantly higher than the wild counterparts. Liquid chromatography of unsaponifiable lipids showed, on a lipid gram basis, higher cholesterol levels in wild fish and comparable amounts of squalene, all- trans retinol, and a-tocopherol. Gas chromatography of total lipids revealed differences between the fatty acid profiles of wild and reared fish. Keywords: sea bass, gilthead sea bream, quality, lipid, aquaculture