Partial replacement of dietary soybean meal by high‐protein distiller's dried grains (HPDDG) supplemented with protease enzyme for European seabass, Dicentrarchus labrax fingerlings

High‐protein distillers dried grains (HPDDG) is a co‐product of ethanol production that uses prefractionation technology. A 70‐day growth trial was conducted to investigate the effect of partial replacement of dietary soybean meal by high‐protein distiller's dried grains (HPDDG) with protease enzyme supplementation (PROXYM ULTRA®) on growth performance, physiological parameters and histological changes of the intestine of European sea bass, Dicentrarchus labrax fingerlings. The results indicated that increased dietary HPDDG levels up to 50% of HPDDG supplemented with protease significantly increases growth performance and feed utilization and improved FCR of sea bass. In addition, replacement of SBM by HPDDG supplemented with protease enhanced feed intake efficiency and the health status of fish. Haematology and serum biochemistry (haemoglobin (Hb)), red blood cells (RBCs), white blood cells (WBCs) and humeral immune parameters including total protein, globulin, cholesterol, lysozyme activity and total antioxidant capacity significantly increased with increase in HPDDG supplemented with protease in the diets. Results of this study indicated that HPDDG supplemented with protease is a good alternative protein source for aquaculture feed and can be included up to 50% as a replacement of SBM without compromising growth performance and physiological parameters of sea bass.