Abstract
The influence of dietary fishmeal (FM) replacement with a mixture (1:1) of spirulina (Arthrospira platensis) and a brown seaweed (Sargassum ilicifolium) in Asian seabass (Lates calcarifer, 45.0±0.2) performance was evaluated. Dietary FM was replaced with the algal mixture at 5 (MIX5%) and 10% (MIX10%) and a diet without algal mixture served as control group. One hundred and thirty five L. calcarifer juveniles were stocked into nine 300-L circular containers (15 fish/tank) filled with seawater (salinity = 46.0±0.2 g L-1; temperature = 31.5±2.5°C) with 80% daily water exchange rate. Each dietary treatment was conducted in triplicate. The experimental feeds were offered to fish thrice daily up to satiation for 60 days. Fish in MIX5% group had the highest weight gain (approximately 12%) that was associated with higher feed intake compare to the control. Viscerosomatic index was reduced in fish fed MIX10% diet compared to control group (8.6 vs. 7.6%). Amylase, alkaline phosphatase, total protease and trypsin activities significantly increased in fish fed MIX5% group (P<0.05). Liver superoxide dismutase activity (36.1 U/mg protein) and glutathione (33.3 µmol/g tissue) level increased in fish fed MIX5% diet. MIX5% group had higher white blood cell counts than other groups. Plasma cholesterol decreased (approximately 20 mg/dL) but plasma calcium content increased in fish fed algal mix-supplemented diets (P<0.05). Plasma triglycerides, total protein, globulin, and alkaline phosphatase decreased in fish fed MIX10% diet. Based on the above-mentioned findings, dietary FM replacement with micro- and macroalgae mixture at 5% is recommended for growth and improving health status in L. calcarifer juveniles.