Biomarkers can help us to take a more pro-active approach to fish welfare
Whilst Paisley is not universally recognised as a centre of fish health excellence, this may be about to change with the complete refurbishment of a ground floor suite at the University of the West of Scotland (UWS) campus in PA1.
WellFish Diagnostics, a spinout company from UWS, is at the vanguard of both the use and development of blood chemistry biomarkers as rapid, non-lethal indicators of fish health and welfare.
As with terrestrial vertebrates, the blood of fish contains a wide variety of electrolytes, minerals, enzymes and other proteins (the biomarkers) the presence of which serve to maintain physiological homeostasis – a key component and indicator of health and welfare. Upsets to this balance normally indicate that something might be wrong.
Practitioners in the worlds of human and terrestrial veterinary medicine have been using these biomarkers for decades as indicators of the health status of their patients. Until recently, however, their routine use in aquatic veterinary medicine has been very limited, with PCR, histology and microbiology being the preferred tools of the trade.
Scientists at WellFish, in collaboration with industry partners, have elucidated sets of biomarker signatures which are characteristic of a number of fish health profiles and, as such, are indicative of them. These include the transition into and out of challenge with SAV as well as very early indication of challenge by waterborne gill irritants such as micro-jellyfish.
It has also been recognised that shifts from normal biomarker profiles (and WellFish know what “normal” looks like) can also be attributed to factors other than infectious disease, including both nutritional and environmental influences.
These revelations have been made possible through the development of a large and robust database of case information, the power of which is beginning to suggest that, rather than reacting to issues when they arise, there is much merit in gaining insight into them beforehand. This effectively means monitoring health rather than simply diagnosing disease.
Monitoring changes in homeostasis, through biomarker assessment, provides farm managers with additional insight into the health status of the stocks in their care, allowing them to execute or delay interventions in ways that optimise outcomes.
By encouraging the routine assessment of these biomarkers in fish stocks, as is currently the case for gill swabbing and lice counting, WellFish is beginning to establish blood biochemistry as the gateway tool that helps managers to decide whether additional techniques, such as PCR, are required. This positions clinical biochemistry as a new and essential application in the world of integrated fish health management.