Biochemical changes during post-larval growth in white muscle of gilthead sea bream (Sparus aurata) fed zinc-fortified diets

摘要

Zinc is one of the most important essential trace elements involved in animal growth; it is the most widely used metal cofactor of enzymes involved in protein, nucleic acid, carbohydrate and lipid metabolism, as well as in the control of gene transcription and other fundamental biological processes. Daily zinc requirements in fish vary as a function of age, growing stage, season and reproductive cycle; on the other hand, many essential metals, such as zinc, are not taken up from water in sufficient amounts to meet the nutritional requirements of the fish diet (Watanabe et al., 1997); it is therefore important to supply them with the diet to prevent deficiencies. Previous studies have demonstrated that red and white muscle from wild specimens of Spams aurata are richer in Zn, Cu and Fe (Carpene et al., 1998) than in farmed fish. However, specimens fed a diet containing 900 mg Zn/kg feed had significantly lower growth with respect to control animals, although they did not present general toxicity symptoms (Serra et al., 1996). Gilthead sea bream is a common teleost in the Mediterranean Sea and is one of the most commonly reared species in intensive aquaculture; however, its mineral requirements have rarely been examined. The present research was mainly concerned with the role of zinc in fish metabolism in order to obtain information on nutritional requirements and to clarify the importance of this element in the biochemistry of muscle.