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Environmental impacts on bacterial ecology of bacteriophage use in aquaculture

Reference: LIFE13 ENV/ES/001048 | Acronym: LIFE ENVIPHAGE



Aquaculture often involves high population densities of fish, increasing the risk of rapid spread of infections and consequent economic losses. In order to reduce the incidence of bacterial infections, the use of prophylactic antibiotics has become generalised practice.

Usually, antibiotics are provided as part of fish food. Unconsumed food and fish faeces containing antibiotics settle at the bottom of raising pens and/or are transported by the water and discharged into the environment, where antibiotics can be ingested by wild fish or settles in sediments. Once in the environment, antibiotics alter the composition of the microbiota, with antibiotic resistant bacteria taking over from non-resistant bacteria. This can lead to serious environmental and human health problems. Consequently, the European Commission has called for “developing effective antimicrobials or alternatives for treatment of human and animal infections” (Commission communication 748, 2011).

Much effort has been made to find environmentally friendly alternatives to antibiotics as prophylaxis agents in aquaculture. However, alternative prophylaxis is not possible in very small fish, among which the losses are greatest. Larvae and young fry cannot benefit from the modern technologies, and are still dependent on massive antibiotic treatments. Also, vaccines are useless for treatment of shellfish.

Bacteriophages (viruses that infect bacteria) are one promising alternative, combining high specificity, high efficiency and protection of the environment. Use of bacteriophages in industrial-level aquaculture has so far not been reported, and the environmental impacts have not been established. Evaluation of the environmental impact of bacteriophages, especially on environmental bacterial ecology, is necessary for their consideration as a veterinary treatment at industrial scale.


The LIFE ENVIPHAGE project aimed to demonstrate that use of bacteriophages in aquaculture has limited effects on environmental bacterial ecology. The project would carry out the following actions:

  • Bacteriophage selection: the bacteriophage groups will be selected according to their physical properties, target bacteria, fish species and others factors;
  • Bacteriophage production at industrial scale: producing through infection of bacterial systems about 30 litres of bacteriophage solution;
  • Phagotherapy at industrial scale: the treatment will be applied at an aquaculture facility at Ria de Aveiro, an estuarine system on the north-western coast of Portugal. In particular, through this action the project will study phagotherapy treatment, only for environmental bacteria, in the early fish development stages (fry);
  • Study of the effects of the treatment on animal models: zebra fish will be infected with fish pathogens and treated with bacteriophages;
  • Monitoring the effects of bacteriophages on commercial fish: Different parameters will be analysed in order to estimate the effect of the treatment on fish survival, growth rate and other parameters.



The ENVIPHAGE project teamevaluated the environmental impacts of bacteriophages on bacterial ecology in aquaculture. They demonstrated that bacteriophages used as alternative to antibiotics have limited effects on bacterial ecology.


During the first 6 months of the project, work was focused on identifying the main key factors that bacteriophages should fulfil to perform against selected targets under real conditions, and on selecting the most appropriate bacteriophages from the collections of the University of Aveiro (Portugal) and AZTI (Spain). Two bacteriophages were selected, taking into account technological requirements, activity over a broad range of water salinity and temperature, and other factors: one active against Aeromonas species (University of Aveiro), and one active against Pseudomonas species (AZTI).


The project team then focused on upscaling the production of the two bacteriophages. The bacteriophages active against Aeromonas was successfully produced in high volumes at industrial scale, but the one active against Pseudomonas was unstable during production and storage, work on it was stopped. The treatment under real conditions was performed using the AS-p1 phage specific for Aeromonas.


The impact of bacteriophage treatment was evaluated on animal models. Firstly, at lab scale on fish infected with target pathogenic bacteria (Aeromonas salmonicida) up to 106 cfu/mL, where no significant differences in survival ratio were found between control and bacteriophage samples, suggesting that bacteriophage therapy could be a feasible alternative treatment for juvenile fish production in aquaculture systems. Secondly, the effect of bacteriophage treatment on human microflora was modelled using a zebrafish model, which suggested that it does not have any effect on human health. Finally, the immuno-stimulatory effect of bacteriophage in model animals was studied, with results showing that exposure to 106 PFU/mL of ASA-1 bacteriophage did not stimulate the immune system of fish.


Full-scale application of the AS-p1 bacteriophage was conducted in a commercial fish farm in Ria de Aveiro (Portugal), at high concentration (105 pfu/ml) in three industrial fry pools, on three occasions. Under different experimental conditions, no adverse effects were recorded on fish gut microbiota or the environmental microbial community.


Therefore, the project team concluded that no risks were identified in animal models or bacterial ecosystems; that real-scale bacteriophage production could be fast, effective, and safe; and that bacteriophages offer a viable alternative to antibiotics to fight pathogens in aquaculture.


Further information on the project can be found in the project's layman report and After-LIFE Communication Plan  (see "Read more" section).


Reference: LIFE13 ENV/ES/001048
Start Date: 01/07/2014
End Date: 30/06/2017
Total Eligible Budget: 820,622 €
EU Contribution: 410,310 €
Project Location:


Coordinating Beneficiary: Fundación AZTI
Legal Status: PNC
Address: Txatxarramendi Ugartea, z/g, 48395, Sukarrieta,
Contact Person: External Team NEEMO-IDOM
Email: Send Email
Website: Visit Website

LIFE Project Map



  • Cleaner technologies
  • Pollutants reduction
  • Agriculture - Forestry


  • food production
  • pollution prevention
  • hazardous substance
  • marine environment
  • alternative technology
  • animal foodstuff
  • animal husbandry
  • fishing industry


Name Type
Fundación AZTI Coordinator
UnivAveiro(Universidade de Aveiro), Portugal Participant
BIOPOLIS(BIOPOLIS, S.L.), Spain Participant
Aguacircia(Aguacircia-Piscicultura, Lda), Portugal Participant