Microbial community composition, nitrification process, and growth of Penaeus vannamei in a synbiotic nursery system inoculated with different probiotic microorganisms.

The aim of this study was to evaluate the effect of using different probiotic microorganisms in the composition of the synbiotic system fertilizer on microbial composition, nitrification process, and growth of Penaeus vannamei in the nursery phase. An intensive nursery was carried out (stocking density: 2000 shrimp m−3) for 40 days, using synbiotic fertilization protocols with different probiotic microorganisms in the following treatments: CW – clear water (control), B – Bacillus , BLP – Bacillus + Lactobacillus + Pediococcus , BLPY – Bacillus + Lactobacillus + Pediococcus + Yeasts (Saccharomyces cerevisiae), BY – Bacillus + Yeasts. In addition to probiotic, the fertilizer used rice bran as the main organic carbon source, molasses, sodium bicarbonate (as a buffer), and water in its composition. The Plankton community was analyzed by direct counting. The abundance of ammonia-oxidizing (AOB) and nitrite-oxidizing (NOB) bacteria were determined using fluorescent in situ hybridization. During the experimental time, a faster control of total ammonia nitrogen (TAN) was observed in BLP treatment. Throughout the trial, the control of nitrite through the nitrification process was not observed in the treatments where synbiotic systems were used. In these treatments, water changes were carried out to keep the concentration below the safe level for the species. The phytoplankton and zooplankton communities were basically dominated by Bacillariophyta and protozoans, respectively. On day 21 of the trial, BLP treatment had a higher abundance of AOB bacteria than CW, BLPY, and BY treatments. On day 39 of the experiment, BLP treatment had more NOB than BLPY and BY. Shrimp had a higher final weight in CW and BLP treatments than in the BY. Yield was higher in BLP, B, and BLPY treatments than in the CW. The use of Bacillus , Lactobacillus , and Pediococcus (BLP treatment) in synbiotic system fertilization promoted rapid control of TAN, a higher abundance of AOB and NOB, and improved shrimp growth performance in intensive nurseries. • Probiotic microorganisms in synbiotic improve ammonia control in shrimp nurseries. • Probiotic inoculation in shrimp nursery with synbiotic system increases AOB and NOB. • Probiotic inoculation improves growth and FCR in shrimp nurseries with synbiotic. [ABSTRACT FROM AUTHOR]