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

Abstract

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.