Left: Rainbow trout eyed eggs. Right: Rainbow trout fry with skin lesions caused by F. psychrophilum and re-isolation of the bacterium from infected fish. Photos: V. L. Donati.

PhD defence about the use of bacteriophages to control bacterial infections in rainbow trout in aquaculture

Monday 10 May 21


Valentina Laura Donati
DTU Aqua
+45 93 51 89 35


Lone Madsen
Senior Researcher
DTU Aqua
+45 35 88 68 26

On 20 May 2021, Valentina Laura Donati will defend her PhD thesis. The defence can be followed online.

The bacterium Flavobacterium psychrophilum is a worldwide problem in salmonid aquaculture. It is responsible of Rainbow Trout Fry Syndrome (RTFS) in fry and Bacterial Coldwater Disease (BCWD) in juvenile and adult fish and it can cause up to 80-90% mortalities depending on the fish size.

Due to the rise of antibiotics resistance and the well-known disruptive effects of antibiotics on the host’s natural bacterial microbiota and on the environment, novel approaches for the control of F. psychrophilum are of urgent need. 

In her PhD study, Valentina Laura Donati, DTU Aqua, has investigated the use of bacteriophages (or phages) for controlling F. psychrophilum infections in rainbow trout. Phages occur naturally in the environment and they are able to infect and kill their specific host-bacteria thus representing a valuable alternative to antibiotics. 

Valentina Laura Donati has conducted laboratory experiments to study the potential of phages administered to rainbow trout fry by fish feed, in the water and as injections to control F. psychrophilum infections. Furthermore, she has evaluated the effects of oral administration of phages and of antibiotics (florfenicol) on the gut microbiota of rainbow trout fry, also in case of disease. Finally, she has studied the potential of using phages to control F. psychrophilum infections in rainbow trout eggs.

About the PhD defence

Valentina Laura Donati will defend her PhD thesis "Bacteriophage-based control of Flavobacterium psychrophilum in rainbow trout. Studies on phage-treatment of rainbow trout at fry and eyed egg stages and effects on gut microbial communities” on Thursday 20 May 2021 at 14.00 (CEST) via Zoom. Find link to Zoom in the box below.


  • Principal Supervisor: Senior Researcher Lone Madsen, DTU Aqua
  • Co-supervisor: Associate Professor Inger Dalsgaard, DTU Aqua
  • Co-supervisor: Professor Mathias Middelboe, University of Copenhagen


  • Senior Researcher Argelia Cuenca, DTU Aqua
  • Research Molecular Biologist Benjamin R. LaFrentz, United States Department of Agriculture, USA
  • Director of Research and Development Hans Petter Kleppen, Nordly Holding AS, Norway

Chairperson at defence

  • Professor Niels Jørgen Olesen, DTU Aqua.
Learn more

A popular science summary of the thesis can be downloaded here

A copy of the thesis is available by e-mail on request. Please contact Valentina Laura Donati, valdo@aqua.dtu.dk

Link to Zoom and guidelines for attending the defence

It is possible to attend Valentina Laura Donati’s defence on Zoom using this link:

Please, enter the meeting 10 minutes prior to the defence proceedings are scheduled to start. 

All participants are muted per default, but we ask you to double check that the microphone is turned off. 

There will be instructions regarding the proceedings in the beginning of the defence. After the members of the assessment committee have had time to raise their questions to the candidate, questions from the audience will be addressed if the remaining time allows for it.