The development of diagnostic techniques to assess anaemia in aquaculture reared Atlantic Salmon (Salmo Salar).

Over the last 12 months anaemia has emerged as a significant threat to fish health in salmon aquaculture in Scotland. Anaemia occurs when there is a lack of red blood cells, reducing the oxygen carrying capacity of the blood and negatively impacting on fish health and production. Through recent SAIC project meetings with the aquaculture partners it was highlighted that the industry has limited practical methods to define the type of anaemia occurring, identify its source and subsequently develop a preventative strategy against it. The Scottish aquaculture industry is looking to establish a haematology monitoring programme, to characterise and quantify the impact of anaemia, but does not currently have access to automated technologies for fish haematology and is reliant on slow, labour intensive and subjective manual techniques. This lack of technological advancement has also resulted in a lack of reference data for the establishment of appropriate 'normal' background levels.

The overall aim of this project is the development and validation of efficient methods to assess anaemia in Atlantic salmon in aquaculture that can be adopted by the industry and included into their regular fish health management programmes. This is being undertaken by the validation of existing veterinary and medical haematology devices for assessment of fish blood, which is considerably more difficult owing to fish blood cells being nucleated. However once the relevant techniques are established and validated they shall be used to investigate anaemia in fish and to put those results into the wider context of fish health measured using high throughput, automated medical technologies to assess clinical chemistry and immunology endpoints validated for use with fish in a separate (SAIC funded) project involving the same collaborative partners.

The main benefit and impact of this research shall be improvements in fish health management, increasing fish welfare and growth, subsequently benefiting the industry by a reduction in costs, increased yield and improved product quality.

The development of an appropriate diagnostic system to assess anaemia in salmon aquaculture requires; a) the development and validation of rapid, automated haematological methods for salmon blood, and b) the integration of this haematology data with relevant endpoints on fish health and disease. A holistic diagnostic approach is taken, placing the haematology findings in the context of fish health investigated by the high throughput assessment of biochemistry and immunology endpoints and histological analysis. This innovative approach provides information on the cause of anaemia, thereby allowing identification of solutions. Innovation is needed in the area of blood sample preparation and storage, data interpretation and particularly with the integration of physiological impacts associated with anaemia. There is a current lack of reference values in fish haematology and this work shall contribute towards the establishment of reference data of benefit to the salmon aquaculture industry in Scotland.

In the final stage of the project anaemia in Atlantic salmon from various sites around Scotland shall be identified, defined, quantified and its impact measured using haematological, clinical chemistry and immunology high-throughput analysers integrated into a pro-active mechanised technologically advanced method to assess fish heath.

These techniques are relevant to the salmon aquaculture industry in the UK and internationally and user friendly practical guides and protocols shall be developed along with an engagement workshop to offer hands on training and practice to encourage the inclusion of these techniques throughout the industry, greatly increasing the impact of this research.

The overall project aim is the creation and integration into fish health management of an efficient diagnostic system to assess anaemia in salmon aquaculture that will ultimately lead to a better understanding of disease, rapid diagnosis and increased fish welfare. The specific objectives of the project are:

1) To work with the veterinary and human medical companies to re-purpose and validate laboratory and point of care instruments for haematological analysis of salmon blood in aquaculture: Training in manual haematological methods and morphological haematology shall be undertaken and used for the validation of the novel automated techniques. Detailed non-specialist protocols shall be developed for automated haematology measurements and data interpretation.

2) To use these techniques for the characterisation of anaemia in salmon: Anaemia is a complex condition induced by numerous endogenous and exogenous factors and can involve mechanisms of impaired erythropoiesis, accelerated haemolysis or haemorrhaging. Novel automated techniques will be used to characterise anaemia.

3) To investigate the relationship between anaemia and other stressors in salmon aquaculture and their impact on fish health and immunology: Haematology data needs to be placed in the context of fish health and integrated with relevant endpoints on fish health and disease. Various clinical chemistry and immunology endpoints are investigated using the high-throughput, automated Randox Daytona clinical chemistry analyser, validated for use on fish in a SAIC funded project.

4) To develop a haematology monitoring programme integrated into the work streams of our aquaculture partners: we are focusing on relatively simple, high throughput, rapid, inexpensive technologies to provide the industry with the practical tools needed to integrate widespread analysis of anaemia into their fish health monitoring programmes.

The impact of the project shall be measured on several levels:

Societal: through improved fish health and welfare following the integration of haematology providing rapid identification of the early onset of anaemia, allowing faster implementation of mitigation measures and reduced medical intervention.
Economic: by the reduction of anaemia related costs including mortality, food wastage and health management costs and an increase in productivity increasing company profitability. Automation in fish health diagnostics will help health managers to better streamline their activities, increasing productivity.
Scientific: investigation and knowledge creation into the relationship between anaemia and fish health and the development of automated analysers will facilitate analysis of larger sample numbers and the establishment of meaningful reference intervals. Scientific outputs by way of academic publications.
Environmental: from reduced food waste and use of medication. Environmental benefits shall be seen in the decrease in feed wastage by reducing both the amount of feed needed and the potential level of nutrient enrichment around the cages. Healthier fish shall potentially require less medical intervention, again quantifiable before and after the project.
Knowledge exchange: access of this technology through the publication of research findings in peer reviewed scientific journals, the creation of industry-focused technical booklets and a workshop to demonstrate the application of these techniques creating a wider impact throughout the industry.

The results generated by the project shall be disseminated through both academic and industry publications to ensure the widest possible exposure and shall be covered under an IP agreement acceptable to all partners.

The main benefit from this research shall be seen by the industry partners and by the wider Scottish aquaculture industry as they shall be provided with practical tools for the haematological analysis of fish blood using rapid, automated technique enabling the quick assessment of anaemia in fish. When used in conjunction with the clinical chemistry analyser for biochemical and immunological endpoints this offers a potent tool for a holistic assessment of anaemia and fish health in general.

The proposed development of an in-house rapid, high throughput, cost efficient method to analyse anaemia and its impact on fish health based on haematology and the expression of various clinical chemistry endpoints will provide information on fish health in general and on specific organs in particular, acting as an early warning signal, evident before the physiological or pathological symptoms become apparent and allowing the early deployment of mitigation or treatment measures; preventing spread of disease, loss of condition and death.