Tipping the scales

Researchers study how to keep our gefilte fish healthy

Hebrew University team finds that breeding disease-resistant carp can make aquaculture more sustainable and profitable, and even keep other fish healthier

Gefilte fish, a traditional Passover food. (Mushki Brichta , CC BY-SA 4.0, Wikimedia Commons)
Gefilte fish, a traditional Passover food. (Mushki Brichta , CC BY-SA 4.0, Wikimedia Commons)

As Passover approaches and the cooks in the house are rolling up their sleeves to start preparing the traditional gefilte fish (a kind of fish ball, usually made from carp), scientists are examining how best to keep the fish healthy.

With population growth and increased demand for food, farmers have moved to more intensive cultivation, including in raising fish. In aquaculture, very high numbers of fish are farmed together in ponds, making it easy for pathogens to spread quickly.

Common carp, widely grown in aquaculture, suffer from a disease caused by a type of herpes virus (cyrpinid herpes virus type 3).

But they can be bred to be disease resistant, so that their cultivation is both more profitable (less fish are lost to disease) and more sustainable (there’s less need to use chemicals to prevent or treat disease).

While there is knowledge about the ability of disease-resistant fish to cope with sickness, there has been almost no research into the degree to which they are likely to infect others.

A new study led by Prof. Lior David from the Faculty of Agriculture at the Hebrew University has sought to start plugging that gap.

David and his team carried out experiments that revealed that disease-resistant carp not only have a higher chance of survival but when they carry a virus, are also less likely to infect other fish that are not disease-resistant.

And when fish not bred to be disease-resistant are infected by fish that had been bred to be resistant, they were also less likely to die, the research showed.

Furthermore, the water in tanks with resistant fish had lower viral levels, which also lead to lower infection rates among non-resistant fish in the same tank.

The research was published in the peer-reviewed journal, Nature.

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