Shewanella oncorhynchi isolated from a recirculatory aquaculture system (RAS) in Alberta, Canada

Area of Science:

• Microbiology
• Aquaculture
• Food Science

Background:

• Certain Shewanella species are known to cause seafood spoilage.
• Shewanella from Canadian fish production facilities remain largely uncharacterized.
• Recirculating aquaculture systems (RAS) present unique environments for microbial study.

Purpose of the Study:

• To isolate and characterize Shewanella species from a rainbow trout RAS facility in Alberta, Canada.
• To investigate the potential spoilage capabilities of these isolates on different fish species.
• To analyze the genetic makeup and phylogenetic relationships of the isolated Shewanella.

Main Methods:

• Isolation of Shewanella strains from rainbow trout tank water and biofilters.
• Whole genome sequencing for genetic analysis.
• Gas chromatography to confirm eicosapentaenoic acid production.
• Inoculation experiments on rainbow trout and pink salmon filets.
• Colorimetric analysis of fish filets during storage.

Main Results:

• Two Shewanella strains, S2-3 and FD-1, were isolated from a Canadian RAS facility.
• Both strains possessed genes for eicosapentaenoic acid biosynthesis, confirmed in FD-1.
• FD-1 inoculation caused browning in rainbow trout filets but not in pink salmon.
• Storage time significantly impacted the color parameters (L*, a*, b*) of pink salmon.

Conclusions:

• This research provides preliminary characterization of Shewanella from a Canadian RAS trout facility.
• The findings suggest that Shewanella isolates may have differential spoilage effects depending on the fish species.
• Further research is needed to fully understand the role of Shewanella in aquaculture environments and fish spoilage.