I am studying the effect that sea lice and different feed ingredients have on fish skin, and how properties of the fish skin may be modulated to prevent fish being infected by sea lice.
Sea lice (Lepeophtheirus salmonis and Caligus spp.) are one of the major pathogens affecting the global salmon farming industry and have a significant impact in many areas. The annual loss has recently been estimated to be more than €300 million. They attach themselves to the fish skin and eat the protective mucus and skin layers, causing wounds and supressing the fish immune system.
Although various pharmaceuticals (chemical treatments) are available to help combat sea lice, these are often short-lived as sea lice develop resistance to them. There are also concerns as to the effect of the pharmaceuticals on other wildlife in the local area, and whether these concerns are founded or not, there is great incentive to find an alternative, more natural and sustainable approach to fighting sea lice. Preventing sea lice by using in-feed ingredients would be much easier in use, and cheaper to produce than pharmaceuticals.
Fish feed micro ingredients could help stimulate the immune system of fish and enable them to fight sea lice better themselves – a much more natural approach without the risk of sea lice resistance. It is known that some species and even different family groups of salmon are more resistant to sea lice than others.
This research will also compare the skin of such fishes, looking at differences in cell types, cell numbers, and the presence/absence of certain immune molecules for example. Feed ingredients may modulate fish skin so that it is no longer attractive to sea lice i.e. it more closely resembles that of less susceptible fish and the fish in question are no longer seen as suitable hosts.
This research project will also look at what sea lice are attracted to and repelled by, and hopefully optimise methods for screening potential micro ingredients.
Ultimately, this project will give a better understanding of why some fish are more resistant to sea lice than others and how we may be able to reduce the major impact that sea lice are having on the salmon farming industry through the use of fish feed micro ingredients, whilst at the same time taking small steps towards improving environmental wellbeing and enhancing the sustainability of aquaculture.
