Aquaculture Feed and Fertilizer Resources Information System

European seabass - Nutritional deficiencies

Given that quantitative data on nutrient requirements of European seabass are very limited, specific information relating to signs of nutritional deficiency is scarce. Ascorbic acid deficiency is known to induce poor wound healing in seabass, possibly linked to low levels of n-3 long-chain polyunsaturated fatty acids. Some degenerative myopathy has also been linked to possible deficiency in vitamin E and/or selenium (Lopez-Albors et al., 1995). Dietary oxidized fish oil and poor anti-oxidant status are known to induce skeletal muscle degeneration; decreased red blood cell count, haemoglobin content and haematocrit; and increased erythrocyte fragility with increased levels of muscle thiobarbituric acid reactive substances (Messager et al., 1992). In seabass fed diets containing high levels of vegetable oils in replacement of fish oil, several histo-pathological changes, haemorragea and gill damage have been observed (Papoura and Alexis, 2002). In replacing fish oil with vegetable oils, studies have shown that immune function is not compromised heavily if dietary fish oil is replaced by a blend of vegetable oils supplying a physiologically balanced fatty acid composition, in comparison to replacement with a single vegetable oil (Mourente, Good and Bell, 2005; Mourente et al., 2007).