The biofloc system is one of the novel sustainable aquaculture systems, and adding carbonaceous organic matter is the basis of the system. This study aimed to evaluate the effects of different carbon sources on water quality, biofloc composition, and growth performance of Nile tilapia (Oreochromis niloticus). In this study, one control group (no carbon source addition) and four biofloc treatments with molasses (TM), starch (TS), barley flour (TB), and corn (TC) addition with three replications were considered. Altogether, 160 Nile tilapia with an average weight of 1.7 g were stocked in each of the 300-l tanks (160 l of water volume). The results of water quality indicated that the lowest levels of dissolved oxygen (5.43 mg/l) and pH (7.28) were observed in the TS treatment, which showed a significant difference (P < 0.05) compared to other treatments. There was a significant difference among various treatments in nitrogen compounds and the total density of heterotrophic bacteria. Biochemical quality of biofloc was affected by various carbon sources. The highest levels of protein (31.09%), lipid (3.89%), and ash (32.79%) were observed in TB, TC, and TM treatments, respectively. The largest biofloc size was obtained in TS treatment. The lowest survival rate and the highest level of weight gain of Nile tilapia were observed in control group. In conclusion, the present study showed that different sources of carbon in the biofloc system have different effects on water quality, biochemical composition, and biofloc size produced in cultivation tanks.

生物絮凝系统是新型的可持续水产养殖系统之一，添加碳质有机物是该系统的基础。这项研究旨在评估不同碳源对尼罗罗非鱼（Oreochromis niloticus）的水质，生物絮凝物成分和生长性能的影响。）。在这项研究中，考虑了一个对照组（不添加碳源）和四种糖蜜（TM），淀粉（TS），大麦粉（TB）和玉米（TC）的生物絮凝剂处理，并进行了三次重复。在300升的水箱（每箱160升水）中，总共放养了160头平均重量为1.7克的尼罗罗非鱼。水质的结果表明，在TS处理中观察到最低的溶解氧（5.43 mg / l）和pH（7.28），显示出显着差异（P <0.05）。氮化合物的各种处理与异养细菌的总密度之间存在显着差异。生物絮凝剂的生化质量受到各种碳源的影响。分别在TB，TC和TM处理中观察到最高水平的蛋白质（31.09％），脂质（3.89％）和灰分（32.79％）。在TS处理中获得了最大的生物絮凝物尺寸。对照组中尼罗罗非鱼的最低存活率和最高增重水平。总之，本研究表明，生物絮凝剂系统中的不同碳源对培养池中产生的水质，生化成分和生物絮凝剂大小有不同的影响。