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The production of bioflocs with the solid waste from recirculating aquaculture systems (RAS) and feeding Artemia results in additional nutrient retention and lowers waste discharged from RAS. The solid waste from the drum-filters of two RAS, which stocked European eel (Anguilla anguilla) and Nile tilapia (Oreochromis niloticus), was used as substrate to produce bioflocs in suspended growth reactors, referred to as E-flocs and T-flocs, respectively. Mono-diets consisting of 100% E-flocs and 100% T-flocs were added to culture Artemia, referred as E-Artemia and T-Artemia, respectively, in a laboratory scale test. The efficiency of this feeding regime was investigated. A significant difference was observed in terms of crude protein content (35.59 ± 0.2%) for E-flocs, (29.29 ± 0.95)% for T-flocs, (70.01 ± 0.92)% for E-Artemia and (65.63 ± 0.89)% for T-Artemia. 134 out of the total operational taxonomic units (OTUs) were present in E-flocs and T-flocs from the analysis of high-throughput sequencing data. Most of the shared OTUs belonged to cyanobacteria. C18:1n7 of T-flocs was higher than that of E-flocs (P < 0.05). C18:2n6 of E-flocs was significantly higher than that of T-flocs (P < 0.05). No significant difference was observed in the other fatty acid compositions (P > 0.05). The survival rate of E-Artemia was (22 ± 0.02) %, significantly higher than that of T-Artemia (16% ± 0.02%) (P < 0.05). No significant difference was observed between the average body weight of E-Artemia (2.38 ± 0.40 mg) and E-Artemia (2.91 ± 0.21) (P > 0.05). The EPA of Artemia fed with E-flocs was (3.00 ± 0.46)%, significantly higher than that of T-Artemia (1.57 ± 0.19%) (P < 0.05). This study offers a method for reusing the aquaculture waste, which will be helpful to achieve a zero-pollution discharge for aquaculture systems. Keywords: Bioflocs, Fish waste, Artemia, Recirculating aquaculture system, Suspended growth reactors |
