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Researchers at the Norwegian University of Science and Technology (NTNU) conducted a study to investigate the potential benefits of bacteria-free fish fry for improved farmed fish and food supply. They successfully maintained salmon fry without bacteria for three months after hatching, gaining valuable insights into the relationship between bacteria and fish.

Salmon fry become colonized by bacteria after hatching

Usually, Salmon fry don’t have bacteria during the egg stage but become colonized by bacteria after hatching. Bred fry lack a natural bacterial community, allowing researchers to introduce specific bacteria for observation and analysis.

Researchers discovered that bacteria play a crucial role in influencing the protective skin mucus layer and fat reserves of fish. Salmon exposed to selected bacteria or lake bacteria developed a thicker mucus layer and increased fat reserves compared to those without bacterial exposure.

NTNU’s Professor Ingrid Bakke stated that bacteria-free model systems offer critical insights regarding the bacteria-host interaction. She added that one such example is getting insight on how gut microbiota influence health and development in mammals and humans.

Salmon fry’s notable attributes, including their well-developed size and extended fry phase, make them ideal for research purposes. Their reliance on the yolk sac for nutrition also ensures that researchers can avoid introducing potentially disruptive microorganisms from fish feed during experiments.

Studies focusing on factors affecting bacterial communities

Researchers sought to investigate the factors influencing bacterial communities in newly hatched fish. The study explored how these communities may offer protection against infections and whether early bacterial fry colonization can be controlled. The potential of probiotic treatment, involving the introduction of beneficial microorganisms to enhance fish health and growth, is an area being explored. However, implementing large scale probiotic treatment remains a distant prospect.

Stembiont, a probiotic product designed for larger fish, is currently accessible in Norway. Additional research is underway, supported by the Research Council of Norway’s FRIPRO funding, to explore probiotic usage on a larger scale. The study aims to enhance comprehension of bacterial impact on fish and humans, potentially leading to improved health for both in the future.