Bioflocs enriched with lyophilized açaí (Euterpe oleracea) improved the survival and weight gain of Litopenaeus vannamei post-larvae cultivated in the BFT system

This study evaluates the bioflocs capacity to assimilate and transfer the bioactive compounds present in açaí to post-larvae of Litopenaeus vannamei cultured in the BFT system. In the first experiment, 21 experimental units (1 l) were randomly distributed among seven treatments (control, 2.5, 5.0, 10.0, 20.0, 40.0, and 80.0 mg açaí L−1) in the BFT system without the inclusion of post-larvae and no water change. Every 24 h, for seven days, the respective concentrations of açaí were added to bioflocs. Initial characteristics of the biofloc used were of 0.13 mg TAN L−1, 0.51 mg N-NO2− L−1, 60.5 mg N-NO3− L−1, 245 mg CaCO3 L−1 and 330 mg TSS L−1. In the second experiment, 12 experimental units (20l), all in triplicate, were randomly distributed in four treatments (control, 5.0, 20.0, and 80.0 mg açaí L−1) with 600 post-larvae (twenty-three day-old PL) per tank cultivated in the BFT system for 27 days. The biofloc inoculum used in the second experiment contained 0.52 mg TAN L−1, 0.13 mg N-NO2− L−1, 35.70 mg N-NO3− L−1, 177.5 mg CaCO3 L−1 and 330 mg TSS L−1. Water changes during post-larvae cultivation were performed when the concentration of nitrite and total suspended solids in the water exceeded the safe levels of 1.38 mg L−1 and 500 mg L−1, respectively. In the first experiment, an increase in the antioxidant capacity was observed against peroxyl radicals of bioflocs (p