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Landcatch Natural Selection Reports Pancreas Disease Success.
18th May 2010
Landcatch Natural Selection (LNS), the Scottish international salmon breeding company, has recently been getting recognition within the industry for the transfer of its award winning IPN resistance breeding success to its commercial stocks. This work, carried out in conjunction with The Roslin Institute, which cloned Dolly the sheep, led to the identification of genetic markers for a quantitative trait locus (QTL) which accounts for over 80% of the variation in IPN resistance. Fish with the resistant variant of the QTL have better survivability when exposed to IPN in freshwater or seawater. Every generation of Landcatch eggs and smolts are selected to have a resistance built-in at the IPN QTL. This is an industry first!
More recently the company has turned its attention to solving the problem of pancreas disease (PD), a very different condition. PD is primarily a chronic disease of the heart and skeletal muscles, although the pancreas is also affected. It is caused by an alphavirus. These viruses are more familiar in association with insect borne infections in man and animals but, of late, the PD alphavirus has become a severe problem to salmon farmers. The virus is believed to be transferred horizontally from fish to fish in the sea and can be responsible for major economic losses. In Norway for example, where it is particularly serious, losses in 2009 have been estimated to exceed $150 million.
A commercial vaccine has now been developed against the PD alphavirus, and it shows some level of protection although there are concerns about the duration of this. Using this expensive vaccine can still result in high mortalities in severely affected areas (80% is possible in the worst situation, although 20-40% is more normal). Since there is no suitable therapy, farmers generally have to resort to reduced feeding and careful, stress free, husbandry in the hope of nurturing a crop back to health. Apart from mortality losses, the resultant poor growth of survivors also affects final profit margins from the crop.
In view of the successes achieved with its IPN resistance selective breeding work, LNS has turned its efforts to PD resistance, to see what can be done to improve resistance to this disease in the Landcatch strain of salmon.
Working with PD is much more difficult than with IPN. Since it is a more chronic condition, with many fish suffering damage without dying, and since there is no good experimental infection model with clear-cut results, the normal means of testing siblings for resistance is not reliable. If field testing is used, there is no guarantee that there will be a natural outbreak at a particular site where trial stock are located, so this also is rather uncertain in output. Thus the Landcatch scientists, again working with colleagues in The Roslin Institute and in Ireland, have had to depend on field data from locations in which selected Landcatch fish have been placed where it is known that the disease can be expected to occur and where fish from other origins are also available for benchmarking against, in order to obtain comparative information on the success of the selected stock.
Initial studies were in Ireland, where there has been a long history of losses from the disease. Here an independent study indicated that there were significant differences in response to challenge by PD between the two most popular strains of salmon farmed in Ireland. Figure 1 shows typical results monitored and published by an independent group of scientists.
Click Here to See Figure 1
Figure 1. Comparative mortality of two strains of salmon in four PD outbreak sites
in Ireland in 2003-4. Strain B has been reported to be Landcatch.
Subsequently, in western Norway, where PD is now a very serious problem, smolts supplied by Landcatch were studied on a site in Austevoll. These fish were stocked in autumn of 2008 alongside PD vaccinated smolts from another source and once they had settled they showed the typical good growth pattern of Landcatch fish. During the following summer (2009), when fish were averaging 2kg and thus of very considerable economic value, PD struck the whole area. Fish went off feed, growth ceased and mortalities began to appear.
The Landcatch fish had NOT been vaccinated, which helped to ensure that any differential mortality demonstrated only the value of genetic enhancement and was unrelated to vaccination. The results were remarkable. Losses in Landcatch fish on the site were less than 5%. The mortality range across the adjacent cages, containing the fully vaccinated fish from another source, was between 15-40%.
Click Here to See Figure 2
Figure 2. Comparative mortality from pancreas disease on a Norwegian site where unvaccinated Landcatch smolts had been placed alongside vaccinated fish from a local source.
Unvaccinated Landcatch smolts have been placed in equally challenging PD environments in other areas of Norway over 3 years and each time have shown remarkably high levels of resistance to infection and very low, or indeed no, resultant mortality. LNS collaborates with experts in virology such as Dr David Graham of the Northern Ireland Veterinary Institute, where the PD virus was first isolated and world renowned research institutions such as The Roslin Institute to investigate genetic resistance to virus infection. Identification of quantitative trait loci (QTLs) associated with resistance to PD and their use in breeding will further enhance the high level of resistance observed in Landcatch stock. This process was pioneered by LNS for IPN resistance. Landcatch are continuously looking to add resistance for specific diseases such as PD to the range of traits that are taken into account as part of our individual broodstock fish selections. If QTLs for PD resistance are found, then it will be possible to further increase inherent genetic resistance to PD at every subsequent generation of the four-year breeding cycle.
In the meantime, however, commercial eggs and smolts, derived from the families with the same genetically enhanced resistance to viral disease observed in the Landcatch stocks at Hordaland are now available from Landcatch, and while PD is not yet conquered, field data to date indicate that using Landcatch stock, along with the PD vaccine, can be expected to significantly reduce losses from this scourge, even while the scientists seek the specific QTL(s) that will allow much greater accuracy for individual broodstock selection.
For further information please contact:
Alan Stewart on +44 (0)7767380234
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For the 2009/2010 egg production season we will be using Marker Assisted Selection (MAS) on all our brood fish.
27th August 2009
Following on from the discovery of the location of a major gene (QTL) controlling resistance to IPN, LNS geneticists, working in collaboration with scientists at the Roslin Institute and the Stirling Institute of Aquaculture, have shown that this gene accounts for most of the variation in resistance to IPN. Individual fish will inherit variants of the gene from their mother and father. Those fish that inherit two favourable variants (++) are highly resistant to IPN whilst those with two unfavourable variants (- -) are highly susceptible. Fish with one resistant and one susceptible version (+-) of the gene show intermediate rates of survival when challenged with IPNV.
This discovery was first used to select LNS broodstock in 2007 and has now been further developed to screen all parents of the eggs which will be offered for sale in the forthcoming season, so maximising the number of individuals which carry the gene for improved resistance to IPN. This method will also allow faster progress in the development of resistance to viral diseases in LNS’s elite pedigree broodstock.
Marker Assisted Selection for disease resistance will be used in harmony with LNS’s balanced approach to genetic improvement for robustness and other commercially important traits. At each generation, Landcatch Atlantic salmon are selected to make major improvements in growth and survival, with supportive improvements in other traits including low maturation. These improvements ensure that producers who use the Landcatch strain of salmon are farming a robust fish with a low production cost.
Download a PDF copy of our leaflet below:
English (63kb)
Norwegian (62kb)
Knowledge Transfer Prize for LNS & Roslin Institute
Dr Almas Gheyas wins KTP Centres in
Scotland Best Project Presentation
The Knowledge Transfer Partnership (KTP) Centres in Scotland prize for Best Project Presentation has been won by Dr Almas Gheyas for her work on the Marker-Assisted Selection of salmon carried out for Landcatch Natural Selection (LNS) Ltd. and The Roslin Institute of the University of Edinburgh.
Dr Gheyas is currently in the third year of a project at LNS, Alloa, where she has been working on the successful application of Marker-Assisted Selection for resistance to the viral disease, Infectious Pancreatic Necrosis (IPN). This project has seen the first commercial application of Marker-Assisted Selection in Aquaculture.
“This is cutting-edge technology which is enabling us to continue advancing our salmon breeding, greatly improving the health and welfare of farmed fish around the world,” said Hugh Currie, LNS Chairman. “The contribution which Dr Gheyas has made to the success of this work is invaluable to LNS. We’re delighted therefore that her work, especially her ability to communicate the science behind the improvements we’re making, has been recognised in this way by KTP.
“We also appreciate the role which KTP plays in enabling the breeding specialists we have at LNS and the research scientists of The Roslin Institute to work together to the ultimate benefit of salmon producers worldwide. We have a rich resource of scientific knowledge in Scotland to which, thanks to KTP, we now have good access as a commercial company. Such partnerships can only be of benefit to Scottish businesses with all the sales, jobs and prosperity that entails.”
AquaVision challenge – breeding is the key fundamental
26th September 2008
Hugh Currie, chairman of Landcatch Ltd, was commenting ahead of AquaVision, the industry's biennial business summit held in Stavanger, Norway, for which this year's chosen theme is:'Know the Fundamentals - Create Your Future'.
'The whole industry, across many species, is entering a period of enormous challenge and it's vital that we apply all our technical, knowledge-based resources to keep aquaculture moving forward,' said Mr Currie.
'The fall-out from the credit crunch is already having an impact on consumer buying patterns, including food purchases. In addition, the rising cost of energy and raw materials is putting enormous pressure on the costs of production. It's against this background, therefore, that I believe we need to combine every possible industry resource to promote aquaculture as a sustainable and profitable enterprise which is attractive to investors.
'Too often in the past our industry has tried to address problems on a piecemeal basis. When combating a new disease, for example, the unilateral solution has been to develop a new vaccine. When looking for better feed utilisation, producers have turned to innovative feed products. It's been the same when dealing with fish mortality, environmental impact, growth rates and so on.
'Many of the solutions which have been produced have been very effective, of course. We would have been a lot worse off today without the industry's many new feeds, vaccines, etc. My point, however, is that the contribution of breeding has been overlooked when, in fact, the fundamental fitness of each individual fish should be viewed as the foundation upon which every other innovation should be built.
World class pedigree breeding programmes, which select parent broodstock for their all-round performance, produce individual fish with an enhanced capability of delivering improved results in the commercial environment.'
Genetic Discovery Gives Welfare and
Performance Benefits in Salmon
4th February 2008
Significant improvements in the welfare and commercial performance of Landcatch Atlantic Salmon are being achieved by the Scotland and Chile-based breeding company, Landcatch Natural Selection Ltd. (LNS).
LNS is the first company to successfully locate a major gene which affects resistance to infectious pancreatic necrosis (IPN), a discovery which is now being used commercially to further improve IPN resistance in Landcatch Atlantic salmon.
Initially unveiled in headline terms at AquaNor 2007, as a ‘quantum leap’ in salmon breeding, full details of the breakthrough are now explained in a scientific paper carried in the latest edition of the internationally respected Journal ‘Genetics’. (Houston et al. (2008) Genetics 178:2) and available on the “Genetics” website
Click Here to view paper
The successful location of this important gene is the result of collaboration between geneticists at LNS and scientists at Roslin Institute and the Institute of Aquaculture, Stirling University, whose combined research was based on over 10 years of data and DNA samples collected from pedigree Landcatch Atlantic salmon.
One key discovery is that the identified gene accounts for over 20% of the total variation in IPN resistance within salmon families. The effect of the gene within some individual families, however, is much larger. LNS have used this information to enhance their long-established selection procedures, enabling the company’s geneticists to identify fish with better levels of resistance to IPN, and other viruses, than ever before.
“This is the first time that genetic markers have been used in marker-assisted selection in a commercial breeding programme for fish,” said Dr Alan Tinch, LNS breeding programme director. “It’s an extremely valuable advance which is already delivering significant welfare improvements and enhanced commercial performance.”
For more information please contact:
Chris Mitchell
Email. cmitchell@swim-back.com
Telephone. 01259 272022
