Text written in Basque and translated automatically by Elia without any subsequent editing. SEE ORIGINAL

Zebrafish in the lab

Zebrafish is a common fish in household aquariums, but they also breed this fish in the laboratory for use in research.

Zebrafish is a common fish in household aquariums, and it’s no surprise because it’s a beautiful and vital fish. But they also raise this fish in the lab. Not to beautify the environment, but to use it in research.

It is probably not the most common animal in research centers in the Basque Country or in laboratories around the world, but it is probably the most promising. For this reason, today we will visit two laboratories that work with zebrafish to get a closer look at the advantages of working with this small fish.

Zebrafish is increasingly used in laboratories around the world. It doesn't seem to take the place of the mouse and rat that dominate the labs, but it comes strong. They recently created a platform to promote the use of zebrafish in research, coordinated by AZTI-Tecnalia and called DareNET, from the acronym of the scientific name of zebrafish: I'll take care of it. MIGUEL

ÁNGEL PARDO; AZTI-Tecnalia: The need for a standardized way of working with this animal model created the idea of this platform, the need for everyone to work in the same way. Compared to other animal models, i.e. mammals such as mouse, rat and rabbit, the working method is not standardized: anesthesia procedures, euthanasia protocols, etc. Each laboratory has a way of working that does not take into account how others work. That is why we want to give a big boost to this normalization.

The idea of this platform surged ahead of the need to try to standardize and work all with this animal model in a consensual and common way. Compare other animal models as well as mammals (rats, rats and rabbits) with existing methods and procedures of anesthesia, protocolas of euthanasia, etc. they are not standardized, and each laboratory work in a local way has no account as to how the rest works. And one of the big impulses that would give this type of normalization.

Zebrafish entered the laboratories around the 1970s. Initially, it was used to investigate embryogenesis processes, since it is a very suitable model for embryo growth research, since the zebrafish embryo is transparent and grows very quickly. Imagine, if the magnifying glass is suitable, the growth of the embryo can

be observed. They grow quickly and are easy to grow, making them cheap for the laboratory. And as if that weren’t enough, at AZTI-Tecnalia they had another compelling reason to use zebrafish.

SANDRA RAINIERI; AZTI-TECNALIA: If we use zebrafish as a human model, it will certainly be an even better model for fish. Taking zebrafish as a model, in aquaculture we look for genes resistant to diseases of farmed fish: for turbot, trout...

If we use fish as a model for humans, we serve more reason as a model for fish. And in this line of research we're looking for resistant genes in aquaculture fish stocks like they can be the root, the thunder...

Taking advantage of the experience acquired with zebrafish in aquaculture, the food department also began to use zebrafish embryos as models.

SANDRA RAINIERI; AZTI-TECNALIA: Precisely, we use zebrafish for toxicity tests, we test the toxicity of molecules that can be included in food, additives, pesticides... Eta eraginkortasun-saiakuntzak ere egiten ditugu, organismoari onura ekar diezaioketen molekulak testatzen ditugu. For example, molecules that can lower cholesterol levels, have the potential to lose weight, and such issues.

In the recipe we use the cereal fish to make toxicity tests, we test the toxicity of molluscs as additives, pesticides, which can be introduced into the food. And we also did tests of effectiveness by testing molecules that could have a positive effect on the organism. Molecules that can, for example, lower the level of colesterol, that have the potential to go forward, etcetera.

After all, it is similar to what is done with drugs. Zebrafish has been used for many years to test future medicines. If it is to come to market, a drug must pass several tests in which zebrafish is increasingly used.

They also work with zebrafish in the Miramón Technology Park in San Sebastián.Biobide is a young company, barely three years old, that uses zebrafish to test drugs, that is, to test the safety and efficacy of drugs, they use transgenic zebrafish.

ARANTXA MURIANA; BIOBIDE: We grow our fish here, transgenic or mutants are created here in the lab. They are genetically modified by injection, and once they are created by the founder, they move on to the facility, and when they have matured, when they are able to lay eggs, at two to three months, the whole family begins to mature. Then we make crosses, the male and the female cross, and their eggs are formed. In this way, we create generations. :Out of these

early transgenic embryos, thousands of fish can grow, all with the same trait. Biobiden requires the growth of many generations of fish, as an automated platform allows them to work with hundreds of embryos at the same time. For example, to see if a drug causes side effects in the heart, add the drug to the water in which the fish embryo grows, incubate it for a while, and with this machine, observe one by one the condition of the heart of each embryo.

So, you know, you've probably tried these tiny fish before you tried that pill you swallow before you go to bed or that other cholesterol-lowering drink you drink.