New case study: improving gill health in farmed salmon
Exploring nutritional aspects of gill disease
Gill health is a critical issue in salmon farming worldwide. Gills perform essential functions such as breathing, regulating salts, and removing waste, making them highly vulnerable to environmental stress, pathogens, and farming practices. Over the past decade, gill diseases have become more common, causing higher mortality rates and raising welfare concerns. This project aimed to improve understanding of gill health and develop better diagnostic tools for managing these conditions.
The study focused on identifying molecular markers that indicate gill health, creating a biobank of tissue samples, and exploring how these markers could be used to predict disease risk and improve management strategies. Valued at £791k, the partners were BioMar Ltd, the University of Aberdeen and Scottish Sea Farms.
Researchers collected and analysed samples from three Scottish salmon farms, using three approaches: visual inspection, microscopic examination, and gene expression analysis.
Key findings revealed that traditional visual scoring methods are not reliable for diagnosing gill disease. While gills may look healthy or damaged on the surface, underlying molecular and tissue-level changes often tell a different story. The team identified 462 genes linked to gill inflammation, including those involved in immune response and tissue repair. From this, they developed a panel of around 40 markers for PCR testing, which showed promise for monitoring gill health more accurately.
A feed trial tested whether functional diets could improve gill health, but results showed no significant differences between diets, highlighting the complexity of the issue. The project also created a biobank of 272 gill samples, which will support future research, and began developing predictive models for disease risk, though more data is needed.
This work challenges current diagnostic practices and demonstrates the need for integrated approaches combining molecular tools with traditional methods. By improving early detection and understanding of gill disease, the industry can enhance fish welfare, reduce losses, and improve sustainability.
Future research will refine these diagnostic tools and explore environmental and biological factors contributing to gill disease. Ultimately, this project lays the foundation for better management strategies to protect one of salmon farming’s most vital organs.
The full title of this project is ‘Advancements in gill health management for Atlantic salmon’. The research team often referred to it as 'Nutritional Aspects of Gilli Disease (NAGD)'.
Share this