Sunday, February 18, 2018

19/02/2018: Salmon: A new era in production management, health, nutrition and feed utilisation

by Professor Simon J Davies, Editor International Aquafeed, Professor of Fish Nutrition & Aquaculture, Harper Adams University, England

By 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 there’s nothing fundamentally wrong with adding DNA, gene editing does not involve such a process and salmon subjected to this technique will not be classed as genetically modified in the normal definition.

This contrasts with transgenic modification, where new genes are introduced (sometimes from other species), and RNA interference (RNAi), where DNA is added to effectively turn off or ‘tone down’ gene expression to enable various metabolic processes in the salmon to be controlled such as temperature tolerance and growth rate in typical intensive operations.

Read the full article, HERE.

The Aquaculturists
This blog is maintained by The Aquaculturists staff and is supported by the
magazine International Aquafeed which is published by
Perendale Publishers Ltd

For additional daily news from aquaculture around the world: aquaculture-news

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