1.
34 | INTERNATIONAL AQUAFEED | November-December 2015
EXPERT T●PIC
Welcome to Expert Topic. Each issue will take an in-depth look
at a particular species and how its feed is managed.
TAMBAQUI
EXPERT TOPIC

2.
1 A fish of many names
C
olossoma macropomum may not
exactly roll off the tongue, but it
certainly eradicates the confusion
caused by the variety of alterna-
tive colloquial names this fish goes under:
tambaqui, cachama, gamitana and even pacu
- a term usually employed for other species.
Every dentist should own a tambaqui.
Shaped somewhat like a piranha, this South
American species has a set of teeth more like
those of a human. It is an omnivore, feeding
preferentially on planktonic microcrustaceans
and fruit fallen from the branches of the
flooded forests where the fish also spawns.
Algae, larvae, adult insects and some plant
material are also consumed.
In some countries, for example Panama,
tambaqui are raised in polyculture with tilapia.
Densities vary from one fish per 10m2 when
employing organic fertilisers to one fish per 5
m2 when supplementary feeds or agricultural
by-products are used.
In eight or ten months the fish will reach a
weight of 500 - 1000g, at which point they will
often be sold. If the farmer wants the fish for
himself, however, he will often let them grow
on beyond a year, to over a kilo.
In 2004, the only freshwater fish produced
by Panama accounting for a greater ton-
nage than tambaqui was trout (Oncorhynchus
mykiss), beating the former by only five
tonnes; however, the trout made almost dou-
ble the tambaqui's monetary value.
Why the difference in price? There may
be other reasons, but in the past at least, tam-
baqui certainly had a couple of major draw-
backs in the eyes of your average consumer.
For one thing, it has a lot of Y-shaped
bones distributed through the flesh, unat-
tached to the backbone. These form a nice
supporting mesh for the muscles - great news
for the fish, but not so great for you when
it winds up on your plate. The problem was
viewed as being severe enough that the fish
would require cutting into 'rounds', like slicing
a sausage, rather than the more conventional
fillet.
Another problem was considered to be
storage. Like in many migratory species, the
tambaqui's spine has a large blood supply. The
haeme compounds found in the blood speed
up oxidation of the tissues, quickly leading to
not-so-fresh fish.
Nevertheless, the production figures speak
for themselves: most Europeans may have
never heard of it, but the tambaqui is of
great importance to the economy and food
security of significant areas of Central and
South America. Furthermore, researchers are
currently making progress in addressing less-
desirable aspects of the fish.
Source: FAO
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November-December 2015 | INTERNATIONAL AQUAFEED | 35
EXPERT T●PIC

3.
Tambaqui: is it
possible for this
species to feed
a continental
country?
by Professor Igo G. Guimarães, (Laboratório
de Pesquisa em Aquicultura - LAPAQ
Universidade Federal de Goiás - Campus de
Jataí), Janaína G. Araújo (Post doctorate)
and Graciela P. Martins (PhD), Brazil
W
hen we think about Brazil,
the first thing we have
in mind is happy people,
carnivals and one of the top
beef cattle and soybean producers globally.
However, it seems that the taste or the way
Brazilians perceive fish, one of the healthiest
protein sources available, has been changing
nowadays.
As far as we can date, Brazil has neglected
fish as a protein source in almost all regions
of the country. For example, in 2009 the
average intake of fish by person was only
nine kilograms per person annually, and the
most consumed protein source was chicken
and beef; while fish and fish-products were
the least consumed animal protein. Although
this figure on the dietary preference of the
Brazilian population still continues, data from
The Brazilian Institute of Geography and
Statistics have observed a great increase in fish
consumption rates in Brazil reaching 14.5 kg
per capita in 2013 (MPA, 2014). This increase
in fish consumption has led to the develop-
ment of the aquaculture industry, which, is
now demanding more technology to achieve
market demands for good quality products.
With the current high growth rate of
Brazilian aquaculture, tambaqui (Colossoma
macropomum) is one species that has been
gaining space among a wide variety of aqua-
cultured fish. Tambaqui is the second largest
scaled freshwater fish from Latin America with
naturally occurring habitats of the Amazonian
and Orinoco river basin. It is the second most
farmed species in Brazil, just behind tilapia.
Tambaqui has a societal and economic impor-
tance, mainly for Amazonian people. It is the
main protein source of this population and
specific cuts of tambaqui (such as the ribs) are
becoming highly appreciated internationally
nowadays.
It is a fast growing species reaching 1.2 kg
in just eight months when farmed in net cages
(according to our personal data) and very
adaptable to different raising systems.
Irrespective of the importance of tambaqui
for the aquaculture industry in Brazil, very
little information on nutrient requirements is
available, with insufficient information on how
different diets can affect the characteristics
of the final products of tambaqui. This lack
of information may be responsible for one
problem that has reduced the acceptability of
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36 | INTERNATIONAL AQUAFEED | November-December 2015
EXPERT T●PIC

4.
tambaqui in some regions of Brazil. Consumers usually neglect to buy
tambaqui because of the high fat content of the species, this can account
for 70 percent of the total visceral content depending on fish size.
Based on this problem, our research group has been working
intensively to improve tambaqui diets. We are doing this by providing
nutrient requirement data to assist the feed industry with formulating
species-specific diets for tambaqui.
This is achieved by trying to understand how this fish uses different
sources of nutrients and what the correct balance between protein/
amino acids, carbohydrates and lipids is, as well as the extent to which
we can modulate fat deposition by diet manipulation.
What we know, based on the biology of tambaqui is that this spe-
cies has a very plastic feeding habit, for example, tambaqui in its natural
environment can feed on different food sources such as fruits, nuts
and zooplankton, the proportion consumed between food items varies
according to the raining season.
Additionally, a post-doc researcher (Dr Janaína Araújo) from our
group has been studying how phosphorus (P) nutrition could effect fat
deposition and surprisingly we have observed that this species is able to
efficiently use P from plant sources, which is not a very common feature
of most fish species.
In a series of trials, we have observed that tambaqui and other fish
from the same family can grow well in a diet based solely on plant ingre-
dients and without a P source (usually dicalcium phosphate). Now, we
are studying the mechanisms used by this species to efficiently use P in
plant sources and the P requirement in different life stages.
These results will help to develop diets with low environmental
impact and reduces feed cost which is one of the characteristics of a
sustainable aquaculture production.
The question now is: will tambaqui be able to feed a continental
country like Brazil with its steadily increasing fish intake? Although we
don’t have a definite answer because this involves several links of the
production chain, our group believes that tambaqui can contribute a lot.
The further increase in aquaculture production throughout the world will
have to be on farming of low trophic level fish species (Bené et al. 2015),
such as tambaqui, tilapia and carp. This is due to the low production cost
and the reduced level of fishmeal and/or marine ingredients required in
their diets compared to high trophic level species.
November-December 2015 | INTERNATIONAL AQUAFEED | 37
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5.
Tambaqui can be one of the solutions for
the aquaculture in the tropics, provided that
correct developments in all production chains
take place, from the fish farmer to the fish
processing factories and the consumer. This
could help the industry to put this species on
the table of several families, offering competi-
tive prices and helping assure food security
mainly in low-income communities. In fact,
one of the programs of the Brazilian govern-
ment has been to include fish into children’s
diet in public schools.
We believe that tambaqui can play a spe-
cial role in Brazilian aquaculture. Due to the
economic crisis and the devaluation of Brazil’s
currency, the population will probably reduce
the intake of high valued imported fish such as
Salmon, Tuna and Atlantic Cod.
This can act as an opportunity for
the Brazilian aquaculture industry, which
is based on the farming of low-trophic
level species, to insert their products and
attract consumers. Because this species can
efficiently use plant and animal products,
presents a fast growth rate even without
selective breeding, may be able to efficiently
use P in a vast range of ingredients and has
resistance to management practices in fish
farms, it makes it a strong candidate for
the production of low cost fish products.
However, more information is needed to
accurately determine the potential of this
species. Which type of system will be
more profitable? The impact of nutrition
on the production cost and sustainability of
tambaqui farming will need to be assessed
in order to have a definite answer on the
potential of tambaqui as an improvement
for Latin American aquaculture.
Although the aquaculture industry in Brazil
is not well developed compared to countries
such as Norway, it has the potential to be one
of the world’s leading fish producers. Brazil will
probably have a role of assisting in feeding an
increased world population of approximately
two billion people by 2050, this is due to the
vast freshwater reservoirs and a long coast
which is barely exploited by aquaculture.
We suspect tambaqui will have a special
role on the development of the aquaculture
industry. However, this needs to be done in
association with the development of new
production technologies. It will require a
better understanding of the physiology of
this fish, aiming to reduce the production
cost and increase the efficiency of produc-
tion.
About the research group
Professor Igo G. Guimarães completed
his PhD in Animal Science from Universidade
Estadual Paulista Julio de Mesquita Filho and
his post-docorate from the National Institute
of Nutrition and Seafood Research. He is
currently an associate professor at the Federal
University of Goiás and is located at the Jataí
campus.
As the campus is located in an intensive
agricultural region with a dense soybean, corn
and sorghum plantation, the animal produc-
tion business has developed because of the
availability of low cost grains.
Five years ago they created a research
group, of which Professor Guimarães is
the leader. This group focuses on the
development of tropical fish farming in
the Brazlian Savannah. Within the wider
group, Igo leads the Nutrition section
that is devoted to studying how nutrition
can improve the welfare and growth of
candidate aquaculture species. His team
is composed of two professors, one
post-doctorate, three PhD students, two
graduate students and a technician.
In their laboratory, they mostly develop
trials on nutrient requirements, metabo-
lism and conduct feed evaluations for
tambaqui and pirapitinga species. Other
areas of the group are developed in col-
laboration with other institutions and in
other campuses of the University.
38 | INTERNATIONAL AQUAFEED | November-December 2015
EXPERT T●PIC