Spinal disorder, which can occur relatively frequently among
intensively farmed fish, presents an important health and
productivity challenge for the aquaculture sector. Unfortunately,
there is a lack of information on the underlying molecular
mechanisms involved in bone deformities in fish and other farmed
animals which would help curb this problem.
The team of four scientists from Chile and Norway involved in the
study wanted to improve on this knowledge base by studying the bone
metabolism and pathogenesis of vertebral fusions in Atlantic salmon
(Salmo salar).
The researchers reared 400 juvenile salmon in water at a
temperature of 10°C and a further 400 at a temperature of
16°C. Salmon farmers often use warmer water to increase fish
growth rates, and the two tanks with the two temperatures were
observed over a period of time to document any ensuing differences
as a result of temperature.
Indeed, the study showed that bone and cartilage production was
disrupted when temperatures were elevated. This resulted in an
increased rate of deformities for the 16°C group. This group of
fish grew faster, but more than a quarter (28%) was found to show
some signs of skeletal deformity (compared to 8% of the fish in the
10°C group).
Co-author of the study Dr Harald Takle from the Norwegian
University of Life Sciences in Norway and AVS Chile explained that
the results 'strongly indicate that temperature-induced fast growth
is severely affecting gene transcription in osteoblasts and
chondrocyte bone cells, leading to a change in the tissue structure
and composition'.
The researchers conducted further studies specifically on the
salmon with the vertebral abnormalities and found that the
deformity process involves molecular regulation and cellular
changes similar to those found in intervertebral disc degeneration
in mammals.
The findings add to a considerable body of work produced under the
FINE FISH project. FINE FISH generated new practical knowledge on
how to reduce the incidence of malformations in the major fish
species used in European aquaculture production, and how to apply
this to the professional sector, made up largely of SMEs.
Eleven of the 20 partners that committed time under FINE FISH were
SMEs. Mr Courtney Hough from the Federation of European Aquaculture
Producers (FEAP), FINE FISH's coordinating partner, explained that
the direction of the research, the presentation of results, and the
field trials were shaped by the SMEs' contributions and desire to
be involved. In fact, the impetus for FINEFISH originated from a
hatchery workshop, where the SME participants themselves requested
that such a project be realised.
'The focus given to application of results in a practical manner to
the SME hatchery sector was of extreme importance to the FEAP,
whose key interest was to have clear recommendations for the
improvement of performance in the European fish hatchery sector,'
Mr Hough told Research Headlines.
As a result, there are several tools available on the project's
website including the FINE FISH diagnostic manuals for individual
species (bass and bream, industrial monitoring, cod, trout, and
salmon) and material used in the series of training courses. Mr
Hough noted that the manual, 'Control of Malformations in Fish
Aquaculture: Science and Practice', was one of the key products
developed under the project.
Another important outcome was the establishment of new professional
partnerships between SMEs and the research sector, several of which
have moved on to explore new challenges.
'One of the key messages from this project was that genuine
collective research requires building a solid bridge between the
research and SME participants,' Mr Hough added. 'This means active
participation and commitment within such projects as well as
understanding their limits.'
FEAP estimates that 650 000 tonnes of fish are farmed in the EU
annually (compared to 60 000 tonnes in 1970). Within Europe as a
whole, the total production is more than 1.6 million tonnes. Norway
is a major contributor to Europe's aquaculture sector with over 860
000 tonnes of salmon and trout produced each year.
Hatcheries produce fertilised eggs, larvae, fry and juveniles that
represent the valuable starting materials for the majority of
European fish farmers.
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