FEATURE
Salmon genetics
A new dawn in aquaculture biotechnology Professor Simon Davies (Editor, International Aquafeed, Professor of Fish Nutrition & Aquaculture, Harper Adams University) gives his thoughts on the latest research in the ground-breaking area of genetic modification, genetic editing and transgenic modification in salmon fingerlings and fish fry. He reflects on his extensive research and experience in the academic focused PhD research he examined in Norway.
B
y 2057, fish producers must greatly increase production to meet the rising population and demand for seafood consumption by some 60 million tonnes. As such, aquaculture expansion is largely dependent on good quality fish fry and fingerlings for on growing under a variety of production systems throughout the world. Continued innovations in fish breeding are necessary to provide better strains, which can adapt to new conditions such as containment in closed recirculation systems, like RAS and deep water sea farms. We have seen great advances in fish genetics, with new breeds that have superior growth characteristics, with selection for stamina and robustness to meet the challenges of husbandry and the growing threat of emerging pathogens, and infection from a host of viruses, bacteria and parasites. Although this is the basis for the development of all new aquaculture scenarios, such as the highly successful YY genetically male tilapia as developed by FishGen Ltd in Wales, revolutionising the farming of this fish globally. As well as the introduction of Specific Pathogen Free (SPF) shrimp based on advanced selection techniques from the USA. This has now become particularly significant in the iconic salmon and trout industries.
We routinely farm triploid trout and also triploid salmon, which is being scrutinised as I found out when I examined a PhD thesis on the subject in Norway in 2016.
Genetic improvement, gene editing and transgenic modifications: What sets them apart?
Genetic improvement of salmon for a variety of phenotype traits is now well under way and more recently the pioneering work leading to GMO salmon (AquaBounty Technologies Inc.), becoming the first GMO animal to be approved in legislation to be marketed in the USA, making headline news. Such transgenic fish incorporating new DNA insertion into their genome has raised some controversy, but is being slowly accepted by many and may well be a leader towards raising faster growing salmon attaining their harvest size in half the time, with the additional bonus of having superior feed utilisation in terms of protein and energy assimilation and enhanced feed conversion efficiency. Now the advent of more refined technologies such as gene editing, offers an entirely new dimension in modulating the expression of the salmon genome. This is based on the refinement of the existing gene make-up, and by careful regulation of the transcription of specific genes via molecular editing tools. In this way we can create desirable alterations, without introducing foreign DNA into the final product. Although, in my opinion
34 | January 2018 - International Aquafeed