Pathogen management strategies in aquaculture

Aquaculture faces constant disease risks from pathogens. As modern practices promote pathogen proliferation continuous management is needed to address bacterial, viral, and parasitic infections.

Bacterial pathogens represent one of the biggest challenges globally, and also a major driver of antibiotic usage which must be reduced.

Various bacterial pathogens in fish can cause issues due to their diversity and ability to produce toxins, leading to significant economic losses in the aquaculture industry.

Gram-negative vs Gram-positive bacteria

Bacteria can be divided into two groups: Gram-positive and Gram-negative. The main difference between them is their cell membrane. Gram-positive bacteria have a layer of peptidoglycan, while Gram-negative bacteria have an extra layer made of lipopolysaccharides (LPS). Most harmful bacteria in aquaculture are Gram-negative, which makes them hard to fight because:

  • The LPS layer gives them extra protection
  • LPS can be harmful to aquatic animals
  • They have efflux pumps in their membrane that help them resist antibiotics and other treatments.
Figure 1: Cross-sectional view of the cell membrane of both Gram-positive and Gram-negative bacterial cells | Picture Source: Shutterstock
Table 1: Major aquaculture bacterial pathogens in fish and shrimp. Their Gram-reaction is highlighted in brackets, along with the disease that they cause. Note, the majority of bacterial pathogens are Gram-negative.
Piscirickettsia salmonsis (-ve; SRS)Vibrio parahaemolyticus (-ve; EMS/ AHPND)Aeromonas hydrophila (-ve; Hemmorhagic septicemia)
Moritella viscosa (-ve; Winter ulcer disease)Vibrio harveyi (-ve; EMS/ AHPND, Vibriosis)Edwardsiella tarda (-ve; Edwardsiellosis)
Aeromonas salmonicida (-ve; Furunculosis)Vibrio spp. (-ve; Vibriosis)Edwardsiella ictaluri (-ve; Edwardsiellosis)
Yersinia ruckeri (-ve; Enteric redmouth) Francisella noatunensis (-ve; Francisellosis)
Vibrio anguillarum (-ve; Vibriosis) Streptococcus iniae (+ve; Streptococcosis)
Flavobacterium columnare (-ve; Columnaris disease) Streptococcus agalactiae (+ve; Streptococcosis)
Lactococcus garviae (+ve; Lactococcosis) Mycobacterium marinum (+ve; Mycobacteriosis)
Renibacterium salmoninarum (+ve; BKD)  

Current treatment of disease

Overuse of antibiotics in animal protein production, including aquaculture, leads to antimicrobial resistance. Industry collaboration and action, such as the Chilean Salmon Antibiotic Reduction Program, can help reduce antibiotic use and safeguard human and environmental health. Solutions, including the preventive usage of feed additives and functional feeds are crucial for industry sustainability and community livelihoods.

From exposed to protected

At dsm-firmenich, we have developed a range of nutritional solutions for pathogen management. These solutions proactively manage pathogen abundance and proliferation, lowering the risk of disease whilst reducing the reliance on antibiotics and chemical treatments.


  • Biotronic®

    The Biotronic® line of state-of-the-art enhanced acidifiers support modern farm animals against Gram-negative bacteria.

  • AquaStar®

    AquaStar® comprises the most complete range of aquaculture probiotics for hatchery, feed mill and farms to improve growth and enhance pond and water quality.

  • Digestarom®

    Digestarom® line of phytogenics contain unique blends of herbs and spices, essential oils and other plant extracts to improve palatability and acceptance of feed, support digestion and overall performance of farm animals.