What we found
The gut and skin microbiomes of farmed Atlantic salmon differs from that of wild salmon. But the composition and diversity of salmon microbial communities are dynamic and change rapidly in response to the environment. When farmed salmon are moved to a natural environment its microbiome changes – it becomes more similar to that of wild salmon, and vice versa.
We recorded for the first time in fish a lasting signature of early life experience in the salmon microbiome. Farmed salmon retained a distinct signature of hatchery-rearing, even after transfer to natural conditions.
Why it is important
Both inside and out, our bodies harbour a huge array of microbe communities. Together they make up our microbiome and can impact our health for better or worse. For example: gut bacteria play a critical role in the development of the immune system, can enhance digestion and nutrient uptake, or influence metabolism and growth.
The microbiome is just as important to fish as it is to humans and other animals. Establishing how the environment influences the fish microbiome and, in turn, how this influences fish health is important for improving the sustainability of both wild and farmed populations of fish.
What we did
Our study conducted in the Centre for Sustainable Aquaculture Research (CSAR) at Swansea University examined how farming Atlantic salmon affects their microbiome, compared to that of their wild counterparts.
Wild and farmed juvenile salmon were translocated together into three different experimental environments for six weeks (hatchery; hatchery + enriched diet; and natural). Non-invasive skin mucus and faecal samples were taken before and after the experiment to track how the microbiome of each individual fish changed with time.
What it means
Salmon microbiome is sensitive to environmental factors during early life.
For fish farmers this means early rearing condition affect the microbiome development and potentially the health of the fish throughout life.
This opens an exciting path of future research aiming to improve fish health by promoting the development of a healthy microbiome in early life.
FishBites is a science communication series by the FishBEE research group. The FishBEE team integrates the Centre for Sustainable Aquatic Research (CSAR), based at Swansea University, UK.
This post is based on the research paper authored by Dr Tamsyn Uren Webster and co-authors, entitled Environmental plasticity and colonisation history in the Atlantic salmon microbiome: a translocation experiment. Available here
Uren Webster, TM, Rodriguez‐Barreto, D, Castaldo, G, Gough, P, Consuegra, S, Garcia de Leaniz, C. Environmental plasticity and colonisation history in the Atlantic salmon microbiome: A translocation experiment. Mol Ecol. 2020; 29: 886– 898. https://doi.org/10.1111/mec.15369
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