Effects of adding rotifers on the water quality, plankton composition and growth of Pacific white shrimp, Litopenaeus vannamei juvenile, when cultured with biofloc technology

The objective of this study was to evaluate the effect of the addition of Brachionus plicatilis to Litopenaeus vannamei in a nursery biofloc technology (BFT). Four treatments were used: BFT (without addition of rotifers); BFT‐10 (addition of 10 rotifers mL−1); BFT‐20 (addition of 20 rotifers mL−1) and BFT‐30 (addition of 30 rotifers mL−1), all in triplicate. The shrimp (3.4 ± 0.02 mg) were reared for 42 days at a density of 3000 shrimp m−3. The rotifers were added every 10 days (from day 1 to 30). The final weight (1.26 g) and yield (3.42 kg m−3) were significantly higher at BFT‐30 than those from BFT. The percentage of sucrose‐fermenting gram‐negative bacteria increased and non‐sucrose‐fermenting gram‐negative decreased by the end of the period. The crude protein of bioflocs was significantly higher at BFT‐30 than those from BFT‐10 or BFT treatments, while crude lipid of bioflocs was significantly higher at BFT‐20 and BFT‐30 than the BFT. The best shrimp performance was observed in BFT‐30 and BFT‐20, indicating the benefits of rotifers on enhancing the microbial floc content and growth to L. vannamei in BFT.