A European sea bass [Dicentrarchus (D.) labrax] weaning trial was conducted on the 30- 45 day- post-hatching (dph) reared larvae. Enriched rotifers and Artemia were offered as feed in the same 2 m² tank from the 3^rd to the 30^th dphin NIOF hatchery larval rearing unit. In the present study, the total antioxidant capacity (TAC), catalase (CAT) and superoxide dismutase (SOD) antioxidant parameters, and some hepatic enzymes at early life stages were investigated. Four treatments were conducted in triplicates: control mircodiet (G), dietary marine Bacillus subtilis SH1 probiotic (Mpro), marine chitosan prebiotic (Mpre), and two marine synbiotics mixtures (MS1 and MS2) treated microdiets. The impact of the five microdiets cofeeding and weaning treatments on the 45^th dph early weaned D. labrax larvae fed MPro, MPre, MS1, and MS2 exhibited significant (P < 0.05) length growth similar to that recorded in G. The MS1 and MS2 showed the best length growth performance, survival, SOD and CAT activities, as well as TAC improvement after treatments, compared to G. The larvae fed MS2 and MS1 recorded the highest considerable (P < 0.05) alkaline phosphatase (ALP) and acid phosphatase (AP) enzymes total and specific activities, respectively. The larvae fed Mpre recorded the highest significant (P < 0.05) aspartate aminotransferase (AST) total activity; while, larvae fed Mpro recorded the highest substantial (P < 0.05) AST-specific activity. The larvae fed G recorded the highest meaningful (P < 0.05) alanine aminotransferase (ALT) total and specific activities. In conclusion, mixing marine probiotics and prebiotics in synbiotics treatments improved the European sea bass larval growth, survival, and antioxidant capacity.