Bacillus velezensis LG37 absorbs and utilizes ammonia nitrogen from aquaculture water and enhances the toxicity tolerance of grass carp (Ctenopharyngodon idella) to ammonia (non-ionic ammonium)

High concentrations of ammonia nitrogen lead to multi-organ damage, decreased immunity, and metabolic disorders in aquaculture animals, which cause disease outbreaks. This study mainly screened probiotic strains for good control the concentration identified strain LG37 as Bacillus velezensis according its morphological, 16S rDNA, phylogenetic, genomic data analysis. achieved efficiently purifies water enhances toxicity tolerance grass carp ammonia. The experimental on growth characteristics showed that exhibited a satisfactory trend with 10 types sugar, 17 amino acids, 6 organic carbon or source. Under conditions initial dissolved oxygen at 6±1 mg/L, temperature 27±2°C, pH 7±0.3. Through wastewater treatment equipment, degraded feed protein culture reached up 55.5% 73.6% within one week, respectively. Moreover, acute test, when without was fed carp, safe (non-ionic ammonium) 3.37 mg/L (0.2 mg/L). When 5.11 (0.31 Compared LG37, increased by 51.63% (55%).