Multi-strain probiotics (MSP), comprising diverse bacterial strains, have demonstrated enhanced benefits over single probiotics, challenging the traditional view and expanding the understanding of probiotics as modulators of host microbial communities, contributing to improved growth, digestion, immune responses, and disease control in aquaculture.
This study aimed to assess the effectiveness of multi-strain probiotic (MSP) to inhibit the growth of pathogenic Vibrio harveyi through in vitro and preliminary in vivo assay using Artemia. This MSP consists of strains derived
from various marine organisms, comprising of Lysinibacillus fusiformis strains SPS11, A1 and Lysinibacillus sphaericus NAS32. The MSP demonstrated significant inhibition of Vibrio harveyi as determined by in vitro
antagonistic assays. In addition, this MSP can produce higher biofilm in comparison to V. harveyi. Moreover, the strains in the MSP showed resistance to high temperatures (80, 90, and 100°C) and a wide range of pH (2 to
9). In an in vivo challenge assay using Artemia as preliminary host, the survival rate of Artemia treated with MSP in both concentrations (106 and 108 CFU mL-1) was significantly higher (p<0.05) compared to Artemia without MSP treatment and Artemia challenged with V. harveyi only. Notably, Artemia incubated with MSP at concentration 106 CFU mL-1 showed higher survival rate when challenged with V. harveyi. Therefore, the combination of three isolates from genus Lysinibacillus (L. fusiformis SPS11, L. sphaericus NAS32 and L. fusiformis A1) showed potential to be further explored as MSP on selected aquatic species. Besides, at an enrichment level of 106 CFU mL-1, Artemia can be used as a vehicle to deliver this MSP to aquatic larvae feeding on them. This in vitro and preliminary in vivo assessment study demonstrates that this MSP has the potential to be further explored as
MSP on selected aquatic species.