Probiotics in the rearing of freshwater prawn Macrobrachium rosenbergii (de Man, 1879) in a biofloc system

Abstract

The present work evaluated the daily addition of probiotics (Bacillus subtilis and Bacillus licheniformis), during the rearing of Macrobrachium rosenbergii juveniles in a biofloc system for 40 days. Juveniles (0.12 ± 0.32 g) were stocked in 16 experimental units with bottom area of 0.20 m2, 50 L of useful volume, and an equivalent density of 150 prawns m−2. Four treatments were evaluated: Control (without addition of probiotics), TP1 (1.08 × 105 CFU g−1), TP2 (2.17 × 105 CFU g−1) and TP3 (3.25 × 105 CFU g−1). The treatments were randomly assigned to the experimental units with four replicates each. For quantitative evaluation of probiotic bacteria in the rearing water and in the hepatopancreas of prawns, microbiological analyses were carried out at days 0, 20 and 40. The results indicated a predominance of B. subtilis in the hepatopancreas and B. licheniformis in the water. The bacteria were differentiated by colony morphology and confirmed by Polymerase Chain Reaction (PCR) using species-specific primers. This study demonstrated that concentrations as low as 1.08 × 105 CFU g−1 (TP1) contribute to significantly higher survival (p = 0.014) of M. rosenbergii in Biofloc Technology System (BFT).