Download Physiological disturbances in aquatic organisms

PROFESSOR SÉBASTIEN PLANTE
Physiological disturbances
in aquatic organisms
Professor Sébastien Plante discusses how his study is improving the health of various species endemic
in Canada, including efforts to improve feed and feeding techniques for American lobster larvae
To begin, can you explain the scientific
context of your studies?
This research programme focuses on the field
of aquatic ecophysiology. This is a specialised
discipline between the fields of ecology and
physiology. More precisely, it addresses the
behavioural and physiological responses of
organisms in their environment. Here, the
environment can be taken in the broad sense,
ie. all variables capable of interfering with the
natural processes maintaining the internal
equilibrium (or homeostasis) of the organisms.
Can you outline some of the factors that can
disrupt the homeostasis of an organism?
What is their relative impact?
Physiological disturbances caused by stress can
be classified as primary, secondary and tertiary
responses. Primary responses are associated
with rapid increases in adrenalin and cortisol
concentrations. In the short term, adaptive
responses caused by acute stress are beneficial
since they stimulate secondary responses,
such as increased blood capacity to transport
oxygen (more red blood cells) or energy (more
blood sugar), which enable the organism to
better react to stressful conditions.
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INTERNATIONAL INNOVATION
The problem with stress is its long-term effects
in the form of chronic stress. These kinds of
stresses are responsible for many problems
occurring in organisms, such as heightened
susceptibility to disease, increased metabolic
rate and energy utilisation, reduced growth
rates, suppression of immune responses,
inhibition of gonad maturation or ovulation.
These are known as tertiary responses. In the
field, a rise in water temperature, pollution or
a decrease in prey density can all be factors
that potentially disrupt homeostasis. In
captivity – and more precisely in an aquaculture
context – high individual tank densities, poor
water quality or even food not designed for
the specific species can disrupt the organism
homeostasis. When an organism can no longer
adapt its internal equilibrium or does not receive
adequate nutrients, this will eventually lead to
low growth rate, low fecundity or even death.
grad school in Rimouski Québec, Canada,
where I completed my Master’s degree
and, a few years later, a doctorate on fish
physiology and aquaculture. I was hired
by the Université de Moncton campus
de Shippagan to teach Human Anatomy
and Physiology and Vertebrate Zoology
in the science department. I also teach
Aquaculture in Shippagan’s unique Gestion
intégrée des zones côtières (integrated
management of the coastal zones)
programme. In addition to teaching,
I developed PHENORA. Within this
initiative, I currently have three research
projects – one on American lobster and two
on Atlantic salmon.
Is your project ‘Physiology and Nutrition of
Aquatic Organisms’ (PHENORA) expecting
to reap significant benefits from the control
of the nutrition of aquatic organisms?
The students are the centre of attention
within both my teaching and research. My
philosophy is to always take the time to
answer students. Sometimes this slows
down research but, in the long run, it always
turns out beneficial for all involved.
I find it very interesting to control what
the animals are eating and to study their
physiological responses to this feeding. If, for
example, a fish needs X amount of energy to
live and grow normally, can we change the
proportion of proteins and lipids in their diet
without changing the overall energy level of the
feed? What about the quality of the proteins
and lipids? What would happen if certain
amino acids (the building blocks of proteins) or
certain fatty acids (the building blocks of lipids)
were changed without altering the overall
levels of proteins and lipids? These are some of
the avenues we are exploring.
When did you first develop an interest in
biology? What attracted you to the areas of
human anatomy and physiology, vertebrate
zoology and aquaculture specifically?
I completed a degree in biology in Montréal
Québec, Canada and then registered to
How do you effectively balance your
teaching commitments with your
research endeavours?
Finally, why does the preservation of
wild American lobster populations have
particular importance not only for the
wellbeing of Canada’s marine ecosystem,
but also for its economy?
It is important that humans only collect
what Nature can replace. Many still
remember the catastrophic cod fishery
collapse in the Gulf of Saint-Lawrence a
few years ago which was mostly caused
by overfishing. There is no comparison
with the cod fishery, but still, Homarus
Inc, a non-profit organisation affiliated
to the Maritime Fishermen’s Union (New
Brunswick, Canada), continuously attempt
to maintain the local lobster populations
in good health by releasing juvenile
lobsters in the wild in key locations to
ensure a long-term durable fishery.
PROFESSOR SÉBASTIEN PLANTE
Sustaining
Canadian aquaculture
Intensive fishing has put populations of many commercial species in
jeopardy. Studies conducted by the Université de Moncton are seeking
ways to improve the health and wellbeing of aquaculture organisms, as
well as develop specific fish and lobster feeds to sustain these species
AS ONE OF Canada’s most important fisheries,
lobster is big business. However, as with many
industries, it is vital to promote responsible
practice to avoid unsustainable extraction
and resource decline. The preservation of
lobster populations has become a priority, not
only for the economy, but also the country’s
marine ecosystem.
In order to address the challenge, studies
conducted at the Université de Moncton are
attempting to improve the health of aquaculture
species and simultaneously slow down negative
effects of intensive fishing on the surrounding
environment. Physiology and Nutrition of
Aquatic Organisms (PHENORA) was conceived
by Professor Sébastien Plante, a specialist
in aquatic ecophysiology. Bringing together
ecology and physiology, Plante employs this
hybrid field to observe the wider environmental
impact aquaculture has on organisms, assessing
the multitude of biotic and abiotic factors
disturbing equilibria in such environments.
PHENORA GOALS AND DEVELOPMENTS
Lobster is not the first species Plante has
studied. One of PHENORA’s aims is to
investigate the nutrition requirements of a
range of aquaculture species in the laboratory,
which is a controlled environment. The
researcher has previously worked on Atlantic
cod, winter flounder, haddock, arctic charr
and Atlantic salmon. Each project requires a
large investment of both time and money, and
Plante is keen to acknowledge that his work
does not generate immediate gratification:
“The goals of a research programme are longterm,” states Plante, “so discernible progress
will eventually be seen in a few years from
now. Nevertheless, I have accomplished a few
important milestones.” The evaluation of the
organisms’ stress responses is another main
goal of the research programme. Indeed, Plante
is not only attempting to discover what causes
stress in aquatic organisms, but what measures
can be employed to avoid it too.
the techniques are expensive in terms of feed
and resources. Although this could partly
be attributed to the fact that the feed is not
optimised for American native lobster larvae, it
has created demand for a new feed specifically
tailored to the particular species.
Plante and his dedicated team of researchers
have set out to better understand the lobsters’
nutritional requirement in order to develop
feed that better meets industry needs. The diet
formulation has been designed, but the team
are still researching the most effective method
for administering it to lobster larvae.
LEARNING LOBSTER
Regarding the challenges of feeding larvae,
Plante explains the differences compared with
fish aquaculture: “Feeding fish is relatively
easy. When fish pellets are thrown to a fish the
manner in which it takes the feed is observable
and after a few minutes they become full and
stop feeding. In contrast, lobster larvae are
nibblers, meaning they grab a small piece of
food in the water column, nibble on it, let it go,
grab another piece, and so on. They are not great
swimmers either, so the feed must pass right
in front of them in order for them to catch it.”
Indeed, this fact has made it difficult to develop
new feed that not only meets nutritional needs
but also has the optimal speed of descent.
Combining thorough understanding of these
needs – and those involved in tank design and
water circulation – the team has prevailed,
producing a suitable feed for lobsters – though
feed optimisation is ongoing.
The more diffuse effects of aquaculture feed
have also been addressed by Plante’s lab.
As most cultured fish are carnivores, these
organisms generally required fishmeal, which is
produced from wild fish populations. With the
STAGE I LARVAE OF THE AMERICAN LOBSTER
The research team has been working for a few
years with Homarus Inc and the Coastal Zones
Research Institute Inc (CZRI), in Shippagan,
New Brunswick, Canada. Homarus and
CZRI were set up to develop tools aimed at
sustaining the lobster population in Canadian
waters. In prior efforts, the organisation has
established lobster larvae rearing techniques.
While the results of these efforts are promising,
WWW.RESEARCHMEDIA.EU 31
INTELLIGENCE
DEVELOPMENT OF AQUACULTURE
FEED FOR REARING AMERICAN
LOBSTER LARVAE TO LATE
RELEASING IN THE WILD
OBJECTIVES
• To determine the biochemical profiles of
wild American lobster larvae
• To determine the nutritional needs of
American lobster larvae
• To develop a dry feed specifically design for
American lobster larvae
PARTNERS
Université de Moncton, campus de
Moncton, Canada
Homarus Inc, Canada
Coastal Zones Research Institute Inc,
Canada
FUNDING
Natural Sciences and Engineering Research
Council of Canada – grant no. RDCPJ
395408-09
CONTACT
Professor Sébastien Plante
Principal Investigator
Université de Moncton campus de Shippagan
218 boulevard J-D Gauthier
Shippagan, New Brunswick
E8S 1P6 Canada
SÉBASTIEN PLANTE is Biology Professor
at the Université de Moncton campus
Shippagan, New Brunswick, Canada. He
teaches human anatomy and physiology,
vertebrate zoology and aquaculture. At
present, Plante is conducting research on fish
physiology and fish and lobster nutrition, and
fish ecophysiology in the field.
A MICROPLATE PROTEIN ASSAY
Bringing together ecology and
physiology, Plante employs
this hybrid field to observe the
wider environmental impact
aquiculture has on organisms
increase in worldwide demand of aquaculture
products, and therefore fishmeal, wild fish
populations have suffered a serious blow. The
team has given a great deal of attention to
fishmeal replacement, studying both plants and
other kinds of proteins.
FURTHER STUDIES AND THE FUTURE
Aside from lobster, the team is currently focusing
attention on two other aquatic organisms
within separate projects. The first deals with
Atlantic salmon nutrition, researching fish oil
replacement in the fish feed. The evolution and
sustainability of all fish is based on a steady
influx of essential fatty acids – specifically
docosahexaenoic acid, eicosapentaenoic acid
and arachidonic acid – yet these fatty acids
struggle to be converted from their forerunners,
linoleic acid and linolenic acid. To combat this,
Plante has joined a team from the Université
de Moncton to research a new seed oil –
Ahiflower™ oil – which can be employed as a
replacement for traditional fish oil and acts as a
substitute for natural health effects.
The second project, in collaboration with CZRI,
deals with the valorisation of the by-products of
fishing – or the leftover fish processing, which is
generally used for low-value fishmeal. “The goal
of this project is to develop and improve current
technologies for the extraction, isolation and
characterisation of bioactive ingredients of
marine by-products in order to reduce waste
BLOOD SAMPLE TAKEN FROM AN
ANAESTHETISED ARCTIC CHAR
Phenor
Physiologie et nutrition des organismes aquatiques
Physiology and nutrition of aquatic organisms
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INTERNATIONAL INNOVATION
and increase the proportion of catch
going to value-added markets,” Plante explains.
Through improving understanding of global
gene expression patterns and the digestibility
and physiological function of by-products,
the researchers can test such ingredients on
Atlantic salmon and ultimately commercialise
these by-products and formulas.
In terms of the future, the team plans to apply its
findings on a far broader scale to wild fish. This
presents many challenges as the environmental
variables – water temperature, food density,
pollution etc. – are more unpredictable due
to the larger scale and climatic conditions.
Wild fish also interact in a complex food web,
predating smaller fish and being predated by
larger fish, birds or mammals. Quantifying the
environmental conditions would be a great
achievement, and one that Plante is confident
could one day be a reality. He is hoping to answer
several important questions: “For example, what
does it mean if a fish population is in better
shape than in another area? Is there more food
in the first area or fewer predators? Is there
more pollution in the second area?” The health
and energy transfers of the ocean are still poorly
understood, but it is foreseeable that the team
will make great strides to closing the knowledge
gap, ultimately improving the sustainability
of fish stocks and the valuable food source of
billons worldwide.