Lipid composition and metabolism of European sea bass (Dicentrarchus labrax L.) fed diets containing wheat gluten and legume meals as substitutes for fish meal

The role of dietary protein source on growth performance and lipid metabolism in European sea bass (Dicentrarchus labrax) was investigated, by the evaluation of fat content in different tissues, plasma metabolites, liver lipogenic activity and fatty acid composition of dorsal muscle tissue.Five isonitrogenous (490 g kg− 1 crude protein dry-matter basis) and isolipidic (170 g kg− 1 lipid dry-matter basis) diets with graded levels of wheat gluten, soybean and pea meal in substitution of fish meal were evaluated in European sea bass (initial body weight 23.9 ± 0.1) for 96 days. There was a significant difference (p < 0.05) in dorsal muscle and liver lipid contents. Plasma glucose and cholesterol levels decreased significantly (p < 0.05) as diet included soybean and wheat gluten meal (p < 0.05). The composition of fatty acids in muscle triacylglycerols and phospholipids was affected by vegetable sources as n − 6 PUFA percentage was significantly increased and n − 3 PUFA percentage was significantly decreased (p < 0.05), without modifying EPA/DHA ratio, when wheat gluten and pea meal were included in the diet. The results confirm that the quality and quantity of vegetable protein source could affect lipid metabolism and lipid content in the dorsal muscle of the European sea bass and suggest the possibility of manipulation of the diet for commercial purpose.

► We tested wheat gluten, soybean and pea as ingredients in European sea bass diets.
► The growth performance was not affected by vegetable ingredients.
► Lipid metabolism and tissue distribution were affected by vegetable ingredients.
► PCA of fatty acids allows to space out fish fed fish meal-based diet from fish fed wheat gluten-based diets.
► Dietary soybean decreased lipid, namely cholesterol, in sea bass muscle and plasma.