A new research project headed up by DTU Vet is seeking to use feed containing natural antibodies to combat pathogenic bacteria as a replacement for treating fish fry with antimicrobial agents. The antibodies are derived from fish blood. The Danish  Agritech Agency’s Green Development and Demonstration Programme (GUDP) has granted the project funding of DKK 5.7 million. 

“Aquaculturists are increasingly choosing to vaccinate rather than treat with antimicrobial agents, but the immune system in fry is not sufficiently developed to allow vaccines to have the desired effect. As a result, treatment with antimicrobial agents is currently the only effective way to deal with problematic bacterial infections among fry,” explains Professor Peter Heegaard from DTU Vet, who is heading the research project.

“We want to produce food enriched with antibodies to combat pathogenic bacteria so that we can implement what is known as ‘passive immunization’ of the fry to make them resistant to the infections,” relates Professor Peter Heegaard.

The fish’s immune system will develop the antibodies naturally over time following exposure to the bacteria, but it is hoped that this can be achieved earlier if the fry are fed the relevant antibodies in their feed. 

The project will attempt to harvest the antibodies from blood collected in connection with the standard process for slaughtering fish. The feed will then be tested on fish suffering from bacterial infections including Rainbow Trout Fry Syndrome (RTFS), enteric redmouth disease (ERM) and furunculosis, which are currently responsible for major losses in rainbow trout breeding.