Comparison of two commercial recirculated aquacultural systems and their microbial potential in plant disease suppression

Sammar Khalil,AnnaKarin Rosberg,Ramesh R Vetukuri,Farideh Ghadamgahi,Preeti Panda

doi:10.1186/s12866-021-02273-4

Abstract

BackgroundAquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems, but knowledge about their microbial potential to benefit plant growth and plant health is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have in vitro antagonistic potential towards plant pathogens.ResultsMicrobial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the later hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design.ConclusionsThis study explored the microbial diversity and potential of the commercial RAS with either Tilapia or Clarias as a tool to benefit the aquaponic system with respect to plant growth promotion and control of plant diseases.

Highlights

Aquaponics are food production systems advocated for food security and health
The current study has contributed new knowledge concerning the role of microbial tools in commercially based recirculated aquaculture systems (RAS) as promoters of plant growth and suppressors of disease
The assemblages of microbial taxa at the level of phyla and genera both in Tilapia and Clarias Recirculated aquaculture systems (RAS) suggest the suitability of these systems to be used in aquaponic cultivation

Summary

Introduction

Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, a significant challenge. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have in vitro antagonistic potential towards plant pathogens Major challenges such as climate changes, population increases, limited availability of natural resources, and pandemics threaten food security [1], raising urgent needs to shift to robust and sustainable food production systems [2, 3]. Khalil et al BMC Microbiology (2021) 21:205 food security Their sustainability needs further improvement, as they are complex and more knowledge is needed concerning ideal plant nutrient balances in relation to amounts and types of fish feed, system design, and resilience towards pathogen attack and spread of diseases [6]. Stabilization of the RAS element of aquaponic systems, in terms of water quality parameters such as temperature and pH, is crucial to meet fish, plant and microbial requirements optimally [8, 9] and thereby promote good plant and fish growth

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Results

Conclusion