Seaweeds have increasing importance because of their bioactive compounds and their potential application in different industries. Liquid seaweed extract are commercially used as an agricultural biofertilizer. The current work investigated the potential of a commercial liquid seaweed extract, named TrueAlgaeMax (TAM), as a diet feed additive for Nile tilapia Oreochromis niloticus. Five diets (D₀, D_0.5, D₁, D_1.5, and D₂) were supplemented with different TAM concentrations (0, 0.5, 1, 1.5, and 2%, respectively) to investigate the growth performance, feed utilization, and non-specific immunity of O. niloticus challenged with Aeromonas hydrophila. Healthy mono-sex O. niloticus fingerlings were randomly stocked for 70 days in net enclosures (3 m × 6 m × 1 m) at a density of 20 fish m⁻³ with an average initial body weight of 50 g fingerling⁻¹ (three groups for each treatment with a total of 1080 fish per treatment). Diet D₂ represented the highest weight gain (WG) value (161.29 g), average daily weight gain (ADWG) value (2.30 g day⁻¹), and specific growth rate (SGR) value (2.40% day⁻¹) and achieved the best feed conversion ratio (FCR) value (1.31). In addition, D₂ achieved the highest serum protein (5.47 g dL⁻¹), lysozyme (3.75 μg mL⁻¹), and respiratory burst activity (1.89 mg mL⁻¹). Fish mortality decreased by increasing TAM levels. The GC-Mass data of TAM showed nine main phytochemical compounds belonging to seven different important bioactive groups reported as immunity enhancer and growth promoting and showed antioxidant and antimicrobial properties. The results recommended that increasing the levels of TAM up to 2% as feed additive for O. niloticus diet strongly enhances growth performance, feed utilization, and non-specific immunity of Nile tilapia O. niloticus challenged with A. hydrophila. Considering seaweed additions (dry weight or extract) as aquaculture feed additive is of importance.

海藻因其生物活性化合物及其在不同行业中的潜在应用而变得越来越重要。液态海藻提取物在商业上用作农业生物肥料。当前的工作调查了一种名为TrueAlgaeMax（TAM）的商业液态海藻提取物作为尼罗罗非鱼Oreochromis niloticus的饲料添加剂的潜力。在五种日粮（D ₀，D _0.5，D ₁，D _1.5和D ₂）中添加了不同的TAM浓度（分别为0、0.5、1、1.5和2％），以研究其生长性能，饲料利用率和嗜水气单胞菌攻击的尼罗罗非鱼非特异性免疫将健康的单性罗非鱼鱼种随机放养在网箱（3 m×6 m×1 m）中，密度为20条鱼m ^-3，平均初始体重为50 g鱼种^-1（3只，三天）每个处理组，每个处理总共1080条鱼）。饮食D ₂代表最高的增重（WG）值（161.29 g），平均每日增重（ADWG）值（2.30 g第^-1天）和比生长率（SGR）值（2.40％第^-1天）最佳饲料转化率（FCR）值（1.31）。此外，D ₂获得了最高的血清蛋白（5.47 g dL ^-1），溶菌酶（3.75μgmL ^-1））和呼吸爆发活性（1.89 mg mL ^-1）。通过增加TAM水平可以降低鱼类死亡率。TAM的GC-Mass数据显示，属于七个不同的重要生物活性基团的九种主要植物化学化合物据报道可增强免疫力和促进生长，并具有抗氧化和抗菌特性。研究结果建议，增加TAM水平高达2％作为饲料添加剂尼罗罗非鱼的饮食将大大提高生长性能，饲料利用率和尼罗罗非鱼的非特异性免疫尼罗罗非鱼与挑战嗜水气单。考虑添加海藻（干重或提取物）作为水产养殖饲料添加剂非常重要。