In vitro study of the modulatory effects of heat-killed bacterial biomass on aquaculture bacterioplankton communities

Abstract

Recent studies have shown that the addition of non-viable microbial biomass or their components (postbiotics) to fish feed can modulate the gut microbiome and positively influence fish health in aquaculture systems. However, no information was hitherto available on the use of non-viable microbial biomass to manipulate aquaculture bacterioplankton communities. To fill this gap, here we used an in vitro model to assess the effects of heat-killed biomasses of an antagonistic strain Pseudoalteromonas rubra SubTr2 and a non-antagonist strain Escherichia coli DH5α on bacterioplankton communities of a recirculating aquaculture system (RAS). Our results showed that these biomasses can have generalist and species-specific effects on aquaculture bacterioplankton structure and function. In addition, they enriched the abundance of bacterial predators, reduced bacterial load and potentially influenced nutrient cycling and pathogen development in aquaculture water. Despite its preliminary nature, for the first time, this study showed that heat-killed microbial biomass has potential application as an in situ modulator of bacterioplankton in aquaculture systems.

From probiotics to postbiotics: Concepts and applications

“…For instance, the thermal inactivation biomass of an antagonistic strain Pseudoalteromonas rubra SubTr2 and a non‐antagonist strain E. coli DH5α increases the abundance of bacteria predators in the water. It reduces bacterial load, which affects nutrient cycling and pathogen development in aquaculture water [163]. Postbiotics prepared from Weissella cibaria isolated from rainbow trout, and Nile tilapia can inhibit the growth of aquatic pathogens and have the potential to become feed additives for the control and prevention of aquaculture diseases [164].…”

Synbiotic Agents and Their Active Components for Sustainable Aquaculture: Concepts, Action Mechanisms, and Applications

“…In aquaculture, postbiotics have been used as growth promoters instead of antibiotics, for immune system stimulation, and as disease control [257,265,266]. Recently, the potential application of postbiotics in aquaculture water quality in order to modulate bacterioplankton communities and influence nutrient cycling and bacterial pathogen abundance was reported [267]. Figure 4 illustrates the potential applications of postbiotics in aquaculture.…”