Abstract
This study was aimed to investigate the effects of dietary supplementation with exogenous enzymes such as phytase and protease enzymes on the growth performance, haemato-immunological, antioxidative status, and intestinal histomorphometry of European seabass (Dicentrarchus labrax). One hundred and fifty Sea bass (Dicentrarchus labrax) fingerlings with an initial body weight of 20 ± 2 g were obtained from Borg Al-Arab, Mariout regain at Alexandria Governorate, Egypt. The fingerlings were stocked into 15 fiberglass tanks (each with 30 m3) at the same. Each tank was stocked with 10 fish. The two exogenous enzymes used for the trial were phytase and protease. Two of the formulated diets were supplemented with the exogenous (phytase and protease at two doses from both 1000 mg kg-1 and 2000 mg kg-1, respectively) and the basal diet served as control diet. Our results concluded that, enzymes play an important role in formulating eco-friendly aqua-feeds. The use of enzymes as a feed additive has rapidly expanded and significant use in aqua-feed. Although the economic and social benefits of enzymes have been well established, the future of feed enzymes is a bright one in the aquaculture industry. From the current study, it can be concluded that dietary supplementation with protease and phytase has the potential to improve the growth performance, haemato-immunological, and antioxidative parameters of cultured sea bass. Additionally, the best inclusion dose of protease and phytase enzymes is a 2000 mg/kg diet. Further quantitative studies are necessary to confirm how exogenous enzymes (especially protease and phytase) modulate intestinal microbiota.

Key words: : Enzymes, Growth performance, Health, Sea bass