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Perspectives on the Utilization of Aquaculture
Coproduct in Europe and Asia: Prospects for Value
Addition and Improved Resource Efficiency
Richard Newton a , Trevor Telfer b & Dave Little b
a Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK , Stirling , FK9 4LA ,
United Kingdom
b University of Stirling, Institute of Aquaculture , Stirling , United Kingdom
Accepted author version posted online: 19 Oct 2012.Published online: 15 Nov 2013.
To cite this article: Richard Newton , Trevor Telfer & Dave Little (2014) Perspectives on the Utilization of Aquaculture
Coproduct in Europe and Asia: Prospects for Value Addition and Improved Resource Efficiency, Critical Reviews in Food Science
and Nutrition, 54:4, 495-510, DOI: 10.1080/10408398.2011.588349
To link to this article: http://dx.doi.org/10.1080/10408398.2011.588349
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Critical Reviews in Food Science and Nutrition, 54:495–510 (2014)
Copyright C
Taylor and Francis Group, LLC
ISSN: 1040-8398 / 1549-7852 online
DOI: 10.1080/10408398.2011.588349
Perspectives on the Utilization
of Aquaculture Coproduct in Europe
and Asia: Prospects for Value
Addition and Improved Resource
Efficiency
RICHARD NEWTON,1TREVOR TELFER,2and DAVE LITTLE2
1Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK, Stirling, FK9 4LA, United Kingdom
2University of Stirling, Institute of Aquaculture, Stirling, United Kingdom
Aquaculture has often been criticized for its environmental impacts, especially efficiencies concerning global fisheries
resources for use in aquafeeds among others. However, little attention has been paid to the contribution of coproducts
from aquaculture, which can vary between 40% and 70% of the production. These have often been underutilized and could
be redirected to maximize the efficient use of resource inputs including reducing the burden on fisheries resources. In this
review, we identify strategies to enhance the overall value of the harvested yield including noneffluent processing coproducts
for three of the most important global aquaculture species, and discuss the current and prospective utilization of these
resources for value addition and environmental impact reduction. The review concludes that in Europe coproducts are often
underutilized because of logistical reasons such as the disconnected nature of the value chain, and perceived legislative
barriers. However, in Asia, most coproducts are used, often innovatively but not to their full economic potential and sometimes
with possible human health and biosecurity risks. These include possible spread of diseased material and low traceability
in some circumstances. Full economic and environmental appraisal is long overdue for the current and potential strategies
available for coproduct utilization.
Keywords Processing, fishmeal, omega-3 oils, regulation, halal, kosher
INTRODUCTION
Fish production from capture fisheries and aquaculture
has received criticism for inefficiency of resources and envi-
ronmental damage. Whereas capture fishery production has
remained fairly static at around 90 million tons, aquaculture
production has steadily increased from 26.7 million tons in
1996 (FAO, 2002a) to 51.7 million tons in 2006 (FAO, 2009a).
Global aquaculture production is dominated by China at
62% by volume in 2009, largely for domestic markets (FAO,
2010). However, the rest of the world has seen rapid expansion,
representing significant trade and income. Globally, aquaculture
continues to be the fastest food growth industry, expanding at
a rate roughly four times that of terrestrial livestock species
combined (FAO, 2009a).
Address Correspondence to Mr Richard Newton, MSc, Institute of Aquacul-
ture, University of Stirling, Stirling, FK9 4LA, UK, Stirling, FK9 4LA, United
Kingdom. E-mail: rwn1@stir.ac.uk
In addition to food capture fisheries, in excess of 30 million
tons of fish are caught each year for nonfood purposes, mainly
for the manufacture of fishmeal and oil for use as feed and
feed supplements in aquaculture, pig, and poultry production
(Figure 1). Aquaculture especially has often been criticized for
inefficient use of fishmeal and oil, which could perhaps be used
for direct human consumption (De Silva and Turchini, 2008)
and for putting pressure on supplies which can threaten ecosys-
tems (Alder et al., 2008). However, little attention has been
paid to the potential for aquaculture to produce fishmeal and oil
to feed other livestock through processing of coproducts. For
the purposes of this review, coproducts are defined as parts of
the animal, other than the fillet, which may have some value
but are often under-utilized. Byproducts are defined as those
parts which cannot readily be used to add value and must be
disposed of. Where mortalities may be considered as byproduct
or coproduct, they will be referred to separately. In 2008, the es-
timated quantity of fish used in fishmeal and oil production was
495
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496 R. NEWTON ET AL.
Figure 1 Trend in price and distribution of global fishmeal production for aquaculture and other use (detail where available). Source: (De Silva 2008; FAO
2002a, 2010; International Monetary Fund 2010; Seafish 2009a, 2010; Tacon and Metian 2008).
20.8 million tons, although this is significantly lower than the
estimated 30 million tons used in 1994 (FAO, 2009a). Although
the quantity of fishmeal used in aquaculture has remained fairly
constant for about 10 years at around 3 million tons, the total
supply has varied greatly, due to El Ni˜
no events for example.
This has resulted in highly fluctuating prices for both fishmeal
and oil and increasing pressure on the aquaculture industry, par-
ticularly that of carnivorous fish such as salmon, which still
consume large quantities of fishmeal.
The reliance of aquaculture on fish oil is even greater than
fishmeal, and is estimated to utilize between 80% and 90% of
global supplies annually, compared to the 1970s when most was
directed toward hydrogenation plants to be converted to trans-
fats, used in margarines for example (Bimbo, 2007). The recent
promotion of omega-3 fatty acids as health promoters has seen
an upsurge in the demand for encapsulated fish oil, growing
at over 4% per annum between 2003 and 2007 in the United
States (Snyder, 2010), putting further pressures on prices and
supplies. As many of the capture fisheries used for fishmeal and
oil production are fully exploited (FAO, 2002b; Fishmeal Infor-
mation Network, 2008), it is becoming increasingly important
to maximize the efficiency of resource use from aquaculture and
fishery products. In addition, with increasing production costs
and competition, profit margins have been squeezed for many
producers (Borch, 1999; Lam et al., 2009). It is therefore be-
coming more important to add value to the product wherever
possible throughout the value chain.
While there has been some research to investigate the poten-
tial for coproducts, lack of knowledge transfer, logistical bar-
riers, and the strict European Union (EU) Animal By-Product
Regulations (European Commission, 2002, 2003) have proven
prohibitive to European products and imports to the Euro-
pean Economic Area (EEA, the 27 EU countries plus Nor-
way, Iceland, and Liechtenstein). Many technologies are avail-
able that enable value to be added through coproducts, and
these are often used innovatively in Asia. However, there are
areas where efficiency can be massively improved in Europe
and Asia by employing such technologies and a full study
of methodologies is long overdue. In some cases, scaling to
commercial levels still remains a challenge in respects to pu-
rification, efficiency, documentation, and verification of health
claims, commercial licensing, and marketability. (Raghavan and
Kristinsson, 2009; Thorkelsson and Kristinsson, 2009). There
has been little progress into how to integrate the technologies
and ideas for the aquaculture sector and the organizational struc-
ture to facilitate their uptake in terms of cost benefit, envi-
ronmental impact, and future projections. However, fish prod-
ucts may have particular advantages over porcine and bovine
products for religious reasons, particularly in Asia, and there-
fore aquaculture products hold significant opportunity for value
addition.
This review discusses the current and prospective technolo-
gies available, previous studies on coproduct, comparisons with
current practices, and how future research and development
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PERSPECTIVES ON THE UTILIZATION OF AQUACULTURE COPRODUCT IN EUROPE AND ASIA 497
Tab l e 1 Fillet yield, expected mortality, and proximate analysis of whole carcass and entire coproduct postfilleting, for farmed Atlantic salmon, striped catfish,
and penaeid shrimp
Fillet Omega-3
Species yield % Mortality % Water % Protein % Lipid % Ash % FA,% total
Whole animal∗
Atlantic salmon 6215265.9318.9313.732.6339.34
Striped catfish 35530676.8712.875.674.07—
Penaeid shrimp 50855974.910 18.010 1.210 3.410 22.9†11
Coproduct
Atlantic salmon — — 62.1316.9319.134.7343.612
Striped catfish — — 73.613 11.813 7.913 5.613 —
Penaeid shrimp — — 69.314 18.914 1.214 5.814 19.114
∗Whole animal figures for striped catfish were taken from fingerlings of average weight 7.6 g. Atlantic salmon and penaeid shrimp figures from market size animals
except †whole shrimp omega-3 content is for Indian white shrimp, Fenneropenaeus indicus at average weight 17.6 g, all others are for the black tiger shrimp,
Penaeus monodon. Coproduct figures are extrapolated from whole fish quantities, fillet yields and quantities.
Source: 1. Ram´
ırez, 2007; 2. SEPA, 2004; 3. Einen and Roem, 1997; 4. Stubhaug et al., 2007; 5. Le Nguyen 2007; 6. Lam et al., 2009; 7. Hung et al., 2010; 8.
Benjakul et al., 2009; 9. Briggs et al., 2005; 10. Focken et al., 1998; 11. Ouraji et al., 2009; 12. Higgs et al., 2006; 13. Polak-Juszczak, 2007; 14. Sriket et al., 2007
should be directed in order to maximize efficiency and sustain-
ability in a number of contexts.
COPRODUCT AVAILABILITY
European Economic Area
Aquaculture in the EEA is dominated by salmonid produc-
tion, particularly Atlantic salmon, the majority of which is
grown in Norway. Here, the combined production of salmonids
was in excess of 800,000 tons in 2008 (Norwegian Directorate of
Fisheries, 2009) and more than the EU27 marine finfish aquacul-
ture production combined (Zampogna, 2009). Estimated fillet
yields from farmed salmonids are about 62%, with 9%, 18%,
9%, and 2% wet weight, making up the viscera, head, backbone,
and skin, respectively (Table 1) (Ram´
ırez, 2007). The most sig-
nificant coproduct streams are viscera at the point of slaughter
and then the heads, bones, and often the skin after transportation
to the processing plants. In some circumstances, the slaughter
and processing may be combined.
Norway exports more than half of its product (Whole Fish
Equivalents, WFE) to the EU as whole/eviscerated fish, mostly
for further processing (Global Agriculture Information Net-
work, 2007) and further exportation within the EU (Figure 2).
Despite this, according to RUBIN (2009) there was at least
60,000 tons of salmon coproduct available in Norway in 2008.
Recently, much of the processing of eviscerated Norwegian
salmon has moved from Denmark and Germany to eastern Eu-
ropean countries, such as Poland (Norwegian Seafood Export
Council, 2009). The United Kingdom, specifically Scotland, is
the second largest producer of cultured salmonids within the
EEA, at around 150,000 tons, an estimated 38% (WFE) of
which is exported (SSPO, 2009). The remainder of fish cul-
tured in Scotland are processed in the United Kingdom along
with an additional 40,000 tons WFE which are imported from
Norway (in 2008) (Norwegian Directorate of Fisheries, 2009).
The UK salmon processing industry has consolidated over
the last 10 years with the number of plants reduced from 145
to 48 but with a slight increase in the number of employees
between 2001 and 2008 (Seafish, 2009a). Consolidation has al-
lowed some processors to produce a range of commodities, such
as Pinneys of Scotland, who produce smoked fillet, mousses,
and ready meals. This trend has the potential for more efficient
use of coproduct. Despite opportunities for value addition from
within the United Kingdom, over 25,000 tons of the estimated
52,400 tons of processing coproduct from UK farmed fish in
2003 was exported (SEPA, 2004).
Aquaculture coproducts have advantages that they are of-
ten more uniform and fresher than those obtained from capture
fishery processing (ˇ
Sliˇ
zyt˙
e et al., 2009). Frequently changing
socio-economic conditions and consumer attitudes have led to
continual restructuring and a fractured nature of the aquacul-
ture processing industry in the EU, resulting in excessive trans-
portation, diffuse availability and a potential loss in quality of
coproduct and potential revenue. Studies have shown that co-
products not only contain significant amounts of omega-3 fatty
acids (FAs) (see Table 1 for proximate analysis and references)
but substances, such as collagen and peptides (see below) which
have potential to yield products of high value.
Currently, companies in Scotland, Norway and Denmark ex-
tract the oils from farmed salmon processing coproducts, and
produce protein concentrates and oils intended for use in pig
or poultry feeds (Thistle Environmental Partnership, 2008). For
example, Hordafor, Denmark, produces around 30,000 tons of
protein concentrate from around 100,000 tons of aquaculture
coproducts per year and also treats mortality waste for biogas
production (see below) (Leivsd´
ottir, 2010 pers. comm.).
Markets for some salmon processing products such as heads
are well established in Vietnam and they can be seen for sale
commonly in major supermarkets as well as in local markets for
around 30,000 VND (about US$1.45) per kilogramme. There
is at least one company in the United Kingdom (Ideal Foods
Ltd.) which exports aquaculture and fishery coproducts to Asia
and other locations. Some Asian countries also import other
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498 R. NEWTON ET AL.
Figure 2 Distribution of farmed eviscerated Atlantic salmon produced in Norway and the UK for further processing during 2008. Source (Norwegian Directorate
of Fisheries 2009; SSPO 2010 unpublished data).
livestock coproducts such as chicken feet from the West. The
import of coproducts demonstrates different values attached to
various animal products by different countries. More research
is required to establish the demand for coproducts in various lo-
cations and weighed against other value addition options closer
to the processing areas.
Although mortalities from production do not enter the human
food chain, they have the potential to alleviate the burden on fish
meal and oil supplies that are suitable for human food produc-
tion, by directing them to feeds for pets and other nonlivestock
feeds. According to De Silva and Turchini (2008), around 13.5%
of the global forage fish catch suitable for fishmeal inputs into
human food production was directed to pets and animals farmed
for their fur in 2002. Chronic fish mortalities (e.g., sea lice in-
fection) amount to between 5% and 10% of the total salmonid
production, for Scotland and Norway (SEPA, 2004; Statistics
Norway, 2009). On occasion acute local or widespread catas-
trophic mortality events occur through disease, algal blooms
(Treasurer et al., 2003), jellyfish (SEPA, 2004; Fisheries Re-
search Services, 2010) or extreme weather (SEPA, 2004). A
weather or disease event may result in the loss or culling of
an entire farm stock of several hundred tons. The slow accu-
mulation of chronic mortalities means they are of little value
but schemes such as "The Fallen Stock Scheme" may allow
for more efficient collection, lower costs, and better utilization
(Bansback, 2006).
Asia
The rapid growth of the aquaculture industry in countries
such as Thailand and Vietnam (particularly peneaid shrimp and
pangasius catfish, mainly striped river catfish, Pangasianodon
hypophthalmus) provides an opportunity for comparison of uti-
lization strategies to the European situation. In these Asian coun-
tries, producers and processors have developed in parallel and
traditionally use a mixture of high and low technology solutions
to utilize aquaculture production and processing coproducts (ac-
cording to stakeholders in the region). The relatively close collo-
cation of production, processing, and support industries in Asia
(particularly Vietnam) provide excellent opportunities to for-
mulate efficient resource use management strategies (Figure 3).
For the reasons above, these strategies may be logistically more
difficult to implement retrospectively in Europe.
Both Vietnam and Thailand are major producers and ex-
porters of penaeid shrimp. In 2007, Vietnam produced 376,700
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PERSPECTIVES ON THE UTILIZATION OF AQUACULTURE COPRODUCT IN EUROPE AND ASIA 499
Figure 3 Production and number of processors of a) Pangasius catfish and penaeid shrimp in the Mekong delta of S. Vietnam in 2008b) Penaeid shrimp in S.
Thailand in 2007. Source: (VASEP 2010, VIFE 2009, Department of Fisheries (Thailand) 2009.
tons of shrimp, a 10-year increase of over 700%, whereas
Thailand produced 501,000 tons which was an increase of more
than 120% over 10 years (FAO, 2009b). Thailand remains the
biggest exporter of shrimp, exporting almost 374,000 tons in
2010 mainly to the United States of America with around 40%
of this preserved or prepared as value-added products such as
ready meals or gourmet products (Thai Frozen Foods Associa-
tion, 2009).
Evidence from processors in Thailand and the Mekong delta
show that there is a large variety of shrimp export products rang-
ing from whole to completely peeled and deheaded, for which,
complete data were not available. These are raw or cooked but
also include partially deshelled and value added. The variety of
shrimp products and the changing market makes the amount of
coproduct available difficult to assess, although for Vietnam it
is estimated at over 150,000 tons (Trang, 2010). Evidence from
VASEP (2010) suggests around half of Vietnamese shrimp is
being exported whole, mainly to Japan, the United States of
America and Europe. Estimates of fillet yields from peneaid
shrimp vary but most reliable figures suggest around 50% of the
animal is fillet (Table 1) for all species (Benjakul et al., 2009).
The vast majority of shrimp mortality occurs in the early stages
when the animals are less than 1 g, therefore they tend to be left
in the pond and are of little value.
In Vietnam, production of the pangasius catfish has grown
from 23,000 tons in 1997 to 1.15 million tons in 2008 (VASEP,
2010). As a consequence, support and fish processing industries
have grown rapidly with over 90% of production processed
locally for export to over 100 countries as frozen fillets (Lam
et al., 2009). However, the expanding industry has also expe-
rienced some of the same problems that the salmon industry
faced two decades ago. Disease has been a major issue for fish
production, resulting in high mortality and consequent use of
antibiotics (Lam et al., 2009). Pangasius catfish farms in An Gi-
ang province, one of the most intensive production areas on the
Mekong delta, commonly report a mortality of up to 30% in the
early-to-mid stages of the production cycle, which subsequently
drops to around 10% in the later stages of production, despite
a reliance on antibiotic-based therapies (Lam et al., 2009).
Possible contaminants in mortality flesh from therapeutants
may limit the opportunities for value addition, even for pet and
fur animal feeds (Nguyen et al., 2006; Lam et al., 2009). Fillet
yield for pangasius catfish is low compared to salmon, typically
ranging between 30 and 40% (Table 1), depending on the cut.
According to some processors, demand is growing for products
such as frozen industrial block, regular cuboid blocks which
can be further processed more easily. This process results in
more trimmings which could be used for many value addition
options.
Key informant interviews of pangasius catfish processors in
Dong Thap and Can Tho provinces in the Mekong region, cou-
pled with direct observation in local markets in Soc Trang, su-
permarkets, and restaurants in several other Mekong provinces
revealed that postfilleting products are commonly on sale for
consumption. These included the catfish stomachs and heads.
According to Nguyen (2010), this is around 5% and the rest is
processed into fishmeal and oil, including viscera, heads, skins,
and trimmings (Le Nguyen, 2007). Fifty-three percent (53%)
of fish meal from coproducts is directed to terrestrial livestock
feeds, and 45% for domestic aquaculture, with the oils sepa-
rated for further sale (Nguyen, 2010). However, traceability can
sometimes be lost (Le Nguyen, 2007) possibly resulting in in-
traspecies feeding of exported products. Tacon (2002) suggested
that some shrimp coproduct may still be used to produce shrimp
feed and is preferred by some farmers. Although these coprod-
ucts provide a readily available protein supply for livestock,
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500 R. NEWTON ET AL.
Tab l e 2 Summary of EU by product categories and regulations on their uses. See below for descriptions of various processes allowable under ABPR
Category Byproduct Allowable uses under ABPR
1. No fish byproducts in Cat. 1
2. •Fish farm mortalities irrespective of cause
•Fish parts collected from the effluent of Cat. 2 processing plants
•Fish parts that contain excessive amounts of veterinary residues
•Cat.3 material that may have been contaminated with Cat. 2.
•Incineration on site or at approved facilities
•Processed in accordance with other ABPR provisions but not for
livestock feeds, cosmetics or medicinal uses
•Feeds for fur, zoo and circus animals
•Ensiled, composted or used in biogas plants, meeting hygiene and
biosecurity measures in the annexes of the ABPR
•Disposed of in landfill if special derogations are applicable
3. •Parts of slaughtered animals considered unfit or not intended for
human consumption
•Fish caught for fishmeal production
•Coproducts from fish processing plants
•Incineration on site or at approved facilities
•Ensiled, composted or used in biogas plants, meeting hygiene and
biosecurity measures in the annexes of the ABPR
•Processed in accordance with other ABPR provisions including
“technical purposes” such as pharmaceuticals and cosmetics
•Used to make livestock feeds but must not be made into fishmeal
for feeding fish unless from wild sources
Source: European Commission 2002, 2003.
they could perhaps be redirected to other industries providing
products of more value.
Some farmers also revealed that fresh mortalities may some-
times be consumed by farm employees or sold to local markets.
While this would be highly unacceptable in the European Union,
it is commonly accepted in Vietnam but it is thought that in most
cases mortalities are being buried. According to evidence from
stakeholders, occasionally, mortalities were reported to be fer-
mented for fertilizer for use on local farms or on the site itself
in small quantities for fruit production.
ANIMAL BYPRODUCT REGULATIONS, LEGISLATION
AND STANDARDS
The further consumption, processing, recycling, transport,
and traceability of aquaculture coproducts, byproducts, and
mortalities from aquaculture and capture fisheries within
the EEA is controlled by the European Animal By-Product
Regulations (ABPR)1and subsequent amendments2(European
Commission, 2002, 2003). These regulations control the use of
animal products which are not intended for human consumption
in order to maintain biosecurity, eliminate contamination of
food and animal feed, and maintain general hygiene. In
particular, they forbid the use of coproducts from cultured
fish processing in the manufacture of fishmeal for the feeding
of other cultured fish, even of different species (European
Commission, 2003). This is because of fears over transmissible
spongiform encephalopathies (TSEs). The byproduct categories
and their allowable uses are summarized in Table 2. There
have been suggestions that the ABPR are inappropriate for
aquaculture (Thistle Environmental Partnership, 2008) as
there is no evidence of TSEs within fish (FAO, 2002b) and
catastrophic mortalities due to nondisease events could perhaps
be better utilized if there were no biosecurity risks. In addition,
1ABPR, Regulation (EC) No 1774/2002
2Regulation (EC) No 811/2003
ABPR do not definitively state at what point postfilleting
products become coproducts or byproducts, not intended for
human consumption. There are many parts of the fish that
could be directed to human consumption at the filleting stage
including cheeks, bellies, and other off-cuts (Ram´
ırez, 2007).
Category 3 byproducts, including coproducts from fish pro-
cessing, have many more options open to their use than Cate-
gory 2 products, such as fish mortalities. At present, Category
3 coproducts can be used in nonfin fish feeds and for human
pharmaceuticals which Category 2 coproducts cannot. In addi-
tion to feeds for animals not intended for human consumption,
ABPR Category 2 or 3 material may be incinerated, composted
in closed containers or used in a biogas production plant (anaer-
obic digestion) but must meet other criteria stipulated in the
ABPR (European Commission, 2002). See Table 2.
From stakeholder and key informant interviews in Vietnam,
regulations in many Asian countries seem to be less strict or
at least less strictly enforced, and there is often a more ad
hoc approach to waste disposal and coproduct use. Certifica-
tion schemes are beginning to acknowledge these issues such
as the WWF Aquaculture Stewardship Council dialogues on
production standards (WWF, 2008, 2009, 2010). Coupled with
regulations imposed by importing nations local regulations may
be tightened and more strictly enforced. If the WWF standards
are widely adopted, the future intraspecies use of processing co-
products for feeds will be strictly prohibited whereas disposal
of catfish mortalities will be limited to fertilizing or “fermenta-
tion,” as well as the European method of incineration or burial
(WWF, 2009). While this may improve traceability and biose-
curity overall, some resource efficiency may be lost until more
technologically advanced solutions are available.
DISPOSAL OPTIONS FOR CATEGORY 2 MORTALITIES
AND BYPRODUCTS
As the EU ABPR do not allow for mortalities to enter the
human food chain, their disposal options are not discussed here
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PERSPECTIVES ON THE UTILIZATION OF AQUACULTURE COPRODUCT IN EUROPE AND ASIA 501
Tab l e 3 Summary of costs, level of expertise, and value addition from options available to mortalities falling into Category 2 of the ABPR
Level of Level of Operating Value of Pathogen
Method capital investment expertise costs product deactivation Comments
Ensiling1Low Low Low Very low Some Interim storage
Feeding to animals2Low Low Low Low If cooked Quality can be too poor
Onsite incineration3Low Low Medium None Yes High air pollution
Landfill3None Low High None No Biosecurity risk
Composting4Low Medium Low Low Yes Unsuitable for large numbers
Anaerobic digestion5High High Low High Thermo-phillic only Markets not well established
for liquid products
Source: 1. Arason et al., 1990; Carswell et al., 1990; Smail et al., 1993; L¨
uckst¨
adt, 2008, 2. Thistle Environmental Partnership 2008; 3. Glanville et al., 2006;
Thistle Environmental Partnership 2008; Local Government association 2008, 4. Glanville et al., 2006; Smail et al., 2009; Inter Trade Ireland 2009, 5. Seafish,
2008; He, 2010; M´
endez-Acosta et al., 2010; Inter Trade Ireland 2009.
in detail, although a summary of available options can be seen in
Table 3. Ensiling is often used to store farm mortalities and also
postfilleting coproduct before transportation for further process-
ing. Ensiling usually involves maceration and storing in plastic
containers, using organic acids at about 2 to 3% v/v to encour-
age autolytic hydrolysis, for interim storage before further treat-
ment or disposal. The process prevents spoilage and odours, and
avoids attracting vermin (Arason et al., 1990; Carswell et al.,
1990; L¨
uckst¨
adt, 2008). Ensiled product using organic acids can
be used as pig and other livestock feeds (Carswell et al., 1990;
L¨
uckst¨
adt, 2008) but acceptance from these industries can be
low (Arason et al., 1990). Organic acids are generally preferred
in all countries, not only because they can be fed to animals,
but because they are less corrosive to equipment and less dan-
gerous to handle than inorganic acids (Carswell et al., 1990).
The product can also be used as a fertilizer if used with other
ingredients (Prescott et al., 1997). These options may also be
useful for Category 3 coproducts in remote locations, for exam-
ple, where higher value addition options may not be feasible.
Ensiling is not generally used as a storage method of shrimp but
Cao et al. (2009) showed that it could be used to extract protein
from coproducts for further use.
VALUE ADDITION OPTIONS AVAILABLE TO
CATEGORY 3 PROCESSING COPRODUCTS ONLY
Fish and Shrimp Meals
Aquaculture has often been condemned for its use of com-
mercial fisheries products in aquafeeds, although its use in
aquaculture has not increased significantly for the last 10 years
(Figure 1). However, global supply is unstable and has led to in-
creasing prices on the global market (FAO, 2009b). The burden
on the fishmeal industry can, therefore, be lessened by supply-
ing coproducts from aquaculture for use in terrestrial livestock
feeds, which would normally be sourced from the reduction in-
dustries. Pig and poultry feeds include reduction fishmeal, con-
taining between 6 and 10% oil (Seafish, 2009b), because of the
health benefits of omega-3 FAs to both the livestock and human
consumers (see below) (Fishmeal Information Network, 2001;
Kouba and Mourot, 2010). Though pangasisus catfish are natu-
rally high in protein, they are low in omega-3 (Polak-Juszczak,
2007), meaning in Vietnam relative performance of livestock
may be better with a fishmeal source high in omega-3. Nguyen
(2010), showed that pigs fed diets containing catfish coproduct
performed well or better in terms of diet intake, growth, meat
quality, and mortality, than diets which included traditional fish
meal sources but commercial data is not available. Figure 5
shows the main methods currently employed in coproduct uti-
lization for the named species.
Although the EU ABPR forbid the use of farmed fish co-
products in fin-fish feeds, the regulations will apparently allow
them to be used in shrimp diets or vice versa. Studies have
shown that capture fishery coproducts can be used in shrimp
feeds with good results (e.g., Sudaryono et al., 1996). Use of
fin-fish byproducts from capture fisheries have also been used in
trials for aquafeeds for other fin-fish species by Goddard et al.
(2008), Whiteman and Gatlin (2005) and Seoka et al. (2008)
amongst others. The results for these studies were mixed.
Shrimp meal has been shown to perform less well than fish-
meal when included in aquafeeds (e.g., Hardy et al., 2005;
Whiteman and Gatlin, 2005). This is attributed to poor avail-
ability of protein (Coward-Kelly et al., 2006; Sachindra et al.,
2006). Although shrimp coproduct has protein levels of 35 to
50%, much is bound to highly indigestible chitin (15 to 25% dry
weight) (Edwards, 2004; Sachindra et al., 2006) and 10 to 15%
as minerals (Sachindra et al., 2006). Digestibility can often be
improved by separation of the chitin by hydrolysis or fermen-
tation (Nwanna, 2003; Coward-Kelly et al., 2006). Autolysis at
ambient temperatures has generally given low yields of usable
products. However Cao et al. (2009) showed that autolysis of
shrimp heads using gradual increase in temperature up to 70◦C
could give protein recovery rates of 88.8%, which can then be
used for animal feeds or flavorings for human consumption (see
below).
Fish Oils
In recent years, there has been much emphasis on the health
benefits of consuming oily fish as part of a balanced diet,
not least because of high omega-3 polyunsaturated fatty acid
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502 R. NEWTON ET AL.
Figure 4 Main routes for utilisation of processing co-products from cultured Atlantic salmon, Pangasius catfish and peneaid shrimp currently employed in the
EEA and SE Asia. Source: Le Nguyen 2007; SEPA 2004 and Stakeholder interviews in the Mekong Delta, Vietnam and S. Thailand.
(PUFA) contents, eicosapentaenoic acid (EPA), and docosohex-
aenoic acid (DHA) which are limited to marine sources. Studies
have shown that maintaining a level of omega-3 to be impor-
tant in reducing factors associated with heart disease (Holub
and Holub, 2004; Domingo, 2007), strokes, thrombosis, mental
health problems and arthritis (Sun et al., 2002). More recently a
high ratio of omega-3 FAs (including EPA and DHA) to inflam-
matory omega-6 fatty acids, common in many plant oils, has also
shown to be important in human health, particularly in prevent-
ing coronary heart disease (Holub and Holub, 2004). In animal
nutrition, inclusion of long chain omega-3 in pig diets has been
shown to improve survival substantially for weaning and suck-
ling pigs and is, therefore, an important dietary component (Fish
Information Network, 2001). At present much of this omega-3
comes from commercial fishmeal (Seafish, 2009b). However, if
necessary, fishmeals with low omega-3 content from pangasius
catfish coproducts, for example, could be supplemented with
oils extracted from salmonid coproduct or other high omega-3
product.
Concentrations of lipid and in turn of EPA and DHA in
farmed salmon viscera are higher than those of the fillet (Sun
et al., 2006), and of many wild captured fish (Figure 4), although
this will depend on the diet of the farmed salmon. A propor-
tion of Scottish salmon, perhaps 10%, are fed higher levels
of fishmeal and fish oil than in other locations to meet con-
sumer demand (Tacon and Metian, 2008). Consumer fears over
Figure 5 EPA and DHA concentrations in the viscera of farmed Atlantic salmon, compared with whole wild and farmed salmon and other commercially
important species. (See Table 1 for total lipid and omega-3 contents in the studied species). Adapted from Sun et al. 2006.
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PERSPECTIVES ON THE UTILIZATION OF AQUACULTURE COPRODUCT IN EUROPE AND ASIA 503
contamination in farmed salmon with persistent organic pollu-
tants (Hites et al., 2004) and heavy metals (Domingo, 2007)
may lead to further fears over bioaccumulation if oils are con-
centrated for health supplements or recycled for animal feeds.
Contaminant levels are generally regarded as being below lev-
els considered to be dangerous to human health (COT, 2006;
Fernandes et al., 2009) and often the refining process removes
many persistent contaminants (Muggli, 2006), especially the
deodorization process using steam distillation, but this may de-
stroy valuable fractions such as carotenoids (Hilbert et al., 1998).
Salmonid visceral oil is of lower quality than that of muscle’s
in terms of lower phospholipids, antioxidants α-tocepherol, and
total carotenoid concentrations (Zhong et al., 2007) but despite
this, visceral oil is less subject to oxidation than muscle oils
(Sun et al., 2006) and aquaculture coproducts can often be sup-
plied fresh (ˇ
Sliˇ
zyt˙
e et al., 2009). Oils are already extracted from
salmon coproducts by simple heating, decanting, and clarifica-
tion by centrifuge, in Denmark by Hordafor, Norway by Scanbio
Ltd., and the United Kingdom by Rossyew Ltd. who also filter
the oil for a purer product. However, the full potential is not
being met. More research is required to determine the markets
for the products and where oils can best be directed. Also, yields
can be improved and the omega-3 fraction separated to higher
purity (Sun et al., 2002) although this may not be cost effective.
Whereas it is important to maximize the use of omega-3 FAs
to relieve the burden on commercial fishmeal and oil reduction
industries, the low omega-3 content in pangasius catfish fat may
mean that other industrial uses may be more appropriate. If cost
effective, these applications can also contribute to resource effi-
ciency of fishmeal and other global inputs within and without the
pangasius catfish value chain. Fish oils have traditionally been
used in the tanning industry for the production of high quality
leather such as chamois, and this is a possible route for oils
produced from mortalities (Thistle Environmental Partnership,
2008). Worldwide, there has been increasing interest in biofuels
as an alternative to fossil fuels, but this has been tempered with
concerns over deforestation and diversion of food products to-
ward the biofuel industry (Sachs, 2007; Piccolo, 2009). Recent
activities have shown catfish coproducts in Vietnam and tilapia
coproducts in Honduras to produce excellent biofuels. Research
into using fish coproducts and mortalities from the pangasius
catfish industry has been gathering pace (Nguyen D.A.T. et al.,
2009; Nguyen T.V. et al., 2009; Piccolo, 2009). Fish oils have
been reported to be excellent fuels because they can be used
in unmodified diesel engines and a high yield can be obtained
from the raw product (Piccolo 2009). Initial attempts produced
fuels which released emissions which were harmful to human
health, but the quality has now improved (Nguyen D.A.T. et al.,
2009).
Fish fat can be broken down into functional biofuels by sim-
ple processes on small or large scales with glycerine as a fur-
ther coproduct that has applications in a number of industries,
e.g., cosmetics (Piccolo, 2009). The oils may be further puri-
fied into fuels of more specific character and use as outlined by
Wiggers et al. (2009), Wisniewski Jr. et al. (2009), and Preto
et al. (2007), and which may meet European Quality Standards
for biofuels, although this needs further attention. According to
Nguyen D.A.T. et al. (2009), between 2005 and 2007 the price
of pangasius catfish fat increased from between 2,000 and 3,000
VND (US$0.10 to $0.14) per kg to about 6,000 VND ($0.28)
per kg due to interest in producing biofuels and there are now
established processing plants in An Giang and Can Tho. The
Can Tho plant has a capacity of around 50 tons per day of raw
material and was exporting its product to Singapore at 11,000
VND (about US$0.60) per liter in 2005 (Agriviet.com, 2009).
Although there is no specific mention of using mortalities or fish
coproducts for biodiesel production in the EU ABP regulations,
the allowance for biogas production and industrial uses should
permit this route which could be of particular interest to remote
or small scale fish-farms and processors in the EU.
Sauces, Pastes and Other Products for Human Consumption
In Europe and other Western countries, direct consumption
options for humans are likely to be limited because of customer
perception, compared to Vietnam and other Asian countries
which import processing coproducts from the West for human
consumption. It is difficult to trace the coproducts, which are
available for value addition from European salmon because of
the diffuse nature of processing and, therefore, the various frac-
tions in each of the major processing countries. The accept-
ability of products to European consumers may differ to their
Asian counterparts and the nature of value-added products will
depend on the quality of the flesh which can be obtained from
the trimmings, etc., and may only allow for commodities such
as fish-balls, mousses or pˆ
at´
es to be produced (Young, 2010
personal communication).
In Thailand, Vietnam, and many other Asian countries, uti-
lization of shrimp coproducts from small capture fishery species
such as krill is fairly well established as fermented goods for
human consumption (Sobhi et al., 2010). There is also an es-
tablished market for mungoon, a shrimp paste made from the
cephalothorax (Binsan et al., 2008). Mungoon is a highly nu-
tritious and healthy food because of high omega-3 FAs, essen-
tial amino acids and calcium ions according to (Binsan et al.,
2008). Despite this usage, the yield of mungoon using traditional
production methods is low, reported at 21.5% of raw material
(Benjakul et al., 2009), leaving substantial amounts of further
coproduct that requires further processing into useful products
or disposal.
In Vietnam, most Pangasius catfish production is directed
toward frozen fillets, but there is also a market for fish sauces,
pastes, and surimi to which some coproducts, such as trimmings
and undersize fish, are directed (Le Nguyen, 2007). Gelman et al.
(2001) and Glatman et al. (2000) described possible techniques
for fermenting fish, using strains of lactic acid bacteria, similar
to the traditional techniques for mungoon, to produce novel
“meat-like” products which could be acceptable to consumers.
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504 R. NEWTON ET AL.
Collagen and Gelatin
Collagens are the most abundant proteins in vertebrates, com-
monly found in connective tissues, especially of the skin but also
bones. There are at least 26 forms (Li et al., 2005) of which the
most abundant and most useful for biomedical and cosmetic
applications is type I (Lee et al., 2001; Li et al., 2005). Its use-
fulness stems from the ease of its extraction in solution and that
it can be shaped into many forms containing tensile fibers which
are biodegradable, biocompatible, and nonantigenic (Lee et al.,
2001). These can be used in many applications including mul-
tiple medical uses such as drug delivery and wound dressings,
cosmetics, and edible food coatings (Lee et al., 2001; Singh
et al., 2011). Collagen extracted from fish swim-bladders, com-
monly called isinglass, has traditionally been used to clarify
beer, (Hickman et al., 2000; Regenstein and Zhou, 2007). Ex-
traction from terrestrial animals is well established, however fish
skins also provide excellent potential for extraction and has been
described by Singh et al. (2011), Sadowska and Kolodziejska
(2005), Muyonga et al. (2004), Aidos et al. (1999) and Eckhoff
et al. (1998) among others. Although yields from fish skins are
generally higher than mammalian (Yunoki et al., 2003), there are
differences in structure and amino/imino acid sequences which
can change the properties of fish collagens compared to higher
vertebrates. Denaturation temperatures are generally lower for
fish which may affect their uses, particularly for human biomed-
ical applications (Nagai and Suzuki, 2000; Yunoki et al., 2003,
2004; Saito et al., 2009), but more work is needed to investigate
how the different properties can best be applied. The thermal
stability of collagen is generally higher in tropical species and
according to Singh et al. (2011), pangasius catfish collagen has
a maximum temperature threshold of around 39.5◦C, similar
to that of commercial porcine collagen. Collagen with lower
thermal stabilities, such as that from salmon, reported as about
19◦C for chum salmon (Yunoki et al., 2003), can be improved
by techniques such as UV irradiation without risking toxicity
that chemical techniques may encounter (Yunoki et al., 2003).
In most extraction studies, fish collagen was split between
acid and pepsin soluble fractions. Singh et al. (2011) described
methods to extract collagen from pangasius catfish skins simi-
lar to other collagen extraction techniques, using NaOH to first
extract noncollagen proteins followed by neutralization and dis-
solving in acetic acid. The acid soluble collagen can then be
precipitated using NaCl and the further fractions obtained from
the filtrate using pepsin hydrolysis to give a combined yield of
12.8% (wet skin weight).
Gelatin is a mixture of proteins prepared from the breaking
of cross-linkages and denaturation of collagen but otherwise is
similar in amino/imino-acid composition to the parent collagen
(Regenstein and Zhou, 2007). Although less valuable per unit
weight, it has vast opportunities for halal and kosher food ap-
plications, most commonly in various sorts of gels for texture,
stabilization, emulsification, and alternatives to fats (Karim and
Bhat, 2009). Fish gelatins of cold and warm water fish, and
terrestrial sources have certain tradeoffs against one another.
Lower melting points of fish gelatins are an issue, and there-
fore those from warm water fish with higher melting points may
be of more value, possibly due to higher imino acid content
(Muyonga et al., 2004; Karim and Bhat, 2009; Shahiri
Tabarestani et al., 2010). However, a major application of
gelatins has been in chilled desserts which could perhaps fa-
vor lower melting point fish gelatins because of better release
of flavors and aromas (Choi and Regenstein, 2000; Boran et al.,
2010) and offer alternative product options because of different
textures and properties (Zhou and Regenstein, 2007). Some ad-
ditives such as neutral salts (Sarabia et al., 2000), sugars (Choi
and Regenstein, 2000), egg albumen (Badii and Howell, 2006) or
treatments with transglutaminase (Yi et al., 2006) may improve
properties but uncertainty exists over the kosher/halal status of
enzyme treatments (Karim and Bhat, 2009). Thermal stability
is of importance in the manufacture of drug and food supple-
ment capsules, which has been suggested as another possible
application for fish gelatins with lower melting points (Karim
and Bhat, 2009). Other applications include possible biomedical
uses such as biocompatible films and fibers with similar proper-
ties to collagen, possibly combined with other biopolymers such
as chitosan described below (Yi et al., 2006). The most desirable
qualities for all applications are high gel strength, viscosity, and
rheological properties, given particularly by the amino/imino
acid contents and lower content of low molecular weight frac-
tions (Eysturskarðet al., 2009; Karim and Bhat, 2009; Badii and
Howell, 2006) but also higher gelatin concentration and matu-
ration temperature, i.e., that at which the gel is allowed to set
(Choi and Regenstein, 2000). The intrinsic physical properties
also tend to be inferior for (especially cold water) fish compared
to mammalian sources, but the extraction process can also have
a significant influence over the quality of the gelatin (Boran
et al., 2010; Shahiri Tabarestani et al., 2010). Generally, it is
extracted by one of two processes, the acid or the alkaline pro-
cess, referring to the pretreatment phase, to produce type A or
type B gelatin, respectively. Low storage and pretreatment tem-
peratures are generally thought to preserve the integrity of fish
gelatin and provide better yields, especially of cold water ori-
gin which are subject to quicker degradation than mammalian
gelatin (Gim´
enez et al., 2005a; Regenstein and Zhou, 2007;
Karim and Bhat, 2009). Pretreatment is usually followed by
hydrolysis in mild organic acids at moderate temperatures of
around 45◦C(Gim
´
enez et al., 2005b; Karim and Bhat, 2009).
The alkaline process has advantages in removing more noncol-
lagenous protein and the following acid neutralization allows
for a weak acid extraction which minimizes damage and gives
high yields of good quality gelatin (Regenstein and Zhou, 2007;
Shahiri Tabarestani et al., 2010). Barriers to the production of
fish gelatins cited by Karim and Bhat (2009) were possible
fishy off-flavors and odors in some species, and problems with
availability of large amounts of consistent raw material, there-
fore economy of scale. If any problems of fishy flavor and odor
are sufficiently addressed, there is vast potential for collagen
and gelatin extraction from the pangasius catfish industry within
the Mekong delta which produces large amounts of consistent
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PERSPECTIVES ON THE UTILIZATION OF AQUACULTURE COPRODUCT IN EUROPE AND ASIA 505
coproduct and has the infrastructure to provide fresh material
and overcome economy of scale difficulties. In Europe, niche
markets for cold water fish gelatins may be less interesting and
may not be able to compete with porcine or bovine sources.
Chitosan and Glusosamine
Chitosan is a polysaccharide which is most commonly made
from the deacetylization of chitin from crustacean shells but
must first be separated from the protein and mineral complex.
Chitosan is an attractive material because it is biodegradable,
biocompatible, exhibits antimicrobial and haemostatic prop-
erties, binds protein and fats, and is soluble in weak acids
(Shahidi, 2007). Chitosan has many commercial applications
depending on the properties provided by the raw material, the
processes used to achieve different degrees of deacetylization
(DD), the molecular weight of the product, and polyectrolytic
properties (Synowiecki and Al-Khateeb, 2003). Applications
include disease-resistant coatings for agriculture and maintain-
ing freshness of produce, in industrial polymers used for paper
and textiles, halal and kosher cosmetics, and medical purposes
such as wound dressings, slow-release drug, and encapsula-
tion technologies. It is also commonly marketed as a slim-
ming aid (Percot et al., 2003; Synowiecki and Al-Khateeb,
2003; Aye and Stevens, 2004; Coward-Kelly et al., 2006; Lalle-
mont, 2008). Commercial processes for its production from
aquaculture coproducts are already well established and usu-
ally involves treatment of shrimp shell with acids to deminer-
alize the calcium content, alkalis to separate the chitin from
the protein and finally deacetylization of the chitin to pro-
duce chitosan (Synowiecki and Al-Khateeb, 2003). Properties
given by high DDs are considered more valuable outlined by
Lertsutthiwong et al. (2002) and Synowiecki and Al-Khateeb
(2003) among others but this requires several deacetylization
steps with washing and drying between each, and high lev-
els of control at each point (Lallemont, 2008). The quantities
of chemicals used have caused environmental concerns (Aye
and Stevens, 2004; Pacheco et al., 2009; Trang, 2010) and can
adversely affect the product (Arment and Guerrero-Legarreta,
2009). Therefore, interest is toward techniques such as enzy-
matic hydrolysis which are potentially more predictable, less
damaging to the product and environment, and that separate
protein and carotenoid fractions for further use (Synowiecki
and Al-Khateeb, 2003; Aye and Stevens, 2004; Coward-Kelly
et al., 2006. More research is required to weigh the various
advantages and disadvantages over traditional methods on eco-
nomic and environmental basis (Synowiecki and Al-Khateeb,
2000; Percot et al., 2003).
The growth in shrimp culture has led to an increase in the
availability of raw material for chitosan production making it
more economically attractive (Coward-Kelly et al., 2006). Chi-
tosan production is low in Vietnam because of environmental
concerns and technological barriers relating to the quality of the
product (Trang, 2010). However, it exports a small proportion
of chitin and shell from shrimp processing to China for chitosan
production which is then further exported worldwide. Evidence
from interviews with Vietnamese shrimp processors also sug-
gests a growing chitin industry in Vietnam but it is losing the
potential to create huge revenues, as the price for chitosan is be-
tween $30 and $150 US per kg, compared to $3.60 and $6 per kg
for chitin (Pichyangkura, 2010). Thailand has a well-established
chitosan industry and dedicated research into its applications,
though more work is needed to establish these markets and as-
sess how they may compete with alternative products such as
collagen for some applications. Currently, around 70% of the
chitin produced is transformed into less valuable glucosamine
products, 10% into oligosaccharides and only 20% into chitosan
(Lallemont, 2008).
Glucosamine is a health supplement which is widely avail-
able in several forms in the United States and Europe. It is
marketed for alleviation for osteoarthritis as it is thought to pro-
mote the formation and repair of cartilage (Lallemont, 2008). It
is formed from the hydrolysis of chitin usually by the action of
acids. The process does not require the same level of control as
chitosan production, though it follows the same initial steps to
produce chitin which is then hydrolysed by the action of acids.
The accessibility of the technology and the developed interna-
tional markets result in it being more favored by industry than
chitosan, but this may change as more applications for chitosan
become apparent, particularly for valuable medical applications
mentioned above (Lallemont, 2008).
Fish and Shrimp Peptides
Hydrolysis techniques are well established in other indus-
tries and are gaining interest in the aquaculture and fisheries
industries for the abstraction of peptides from marine products.
The resulting mixture of peptides is referred to as a protein
hydrolysate. Peptide production by ensiling is unpredictable
(Cancre et al., 1999) because of many different endogenous en-
zymes, and the low pH may destroy some valuable nutritional
elements (Lian et al., 2005) leading to bitter tasting peptides
with unpredictable properties that may be unsuitable for many
applications (Hevrøy et al., 2005). Therefore, more predictable
and controllable forms of hydrolysis are required for the produc-
tion of peptides of particular size and character, which determine
specific properties (Hevrøy et al., 2005; Bourseau et al., 2009;
Vandanjon et al., 2009). This requires commercially available
enzymes in controlled conditions which can give more pre-
dictable results than endogenous enzymes. There are a huge
number of applications for fish protein hydrolysates including
bio-active supplements, health food supplements, food addi-
tives (e.g. emulsifiers and foaming agents), animal feeds and
cosmetics outlined by Thorkelsson and Kristinsson (2009) and
Kristinsson and Rasco (2000) among others. Valuable peptides
can be extracted from fish heads, trimmings, bones, viscera,
shrimp shells, and heads. The processes have been well studied,
but documentation and verification of health claims, with regard
to rigorous in vivo investigation and many marketing aspects to
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506 R. NEWTON ET AL.
achieve full commerciality still need to be addressed (Raghavan
and Kristinsson, 2009; Thorkelsson and Kristinsson, 2009).
The properties given by various peptides is huge and beyond
the scope of this review but smaller peptides (of high degrees of
hydrolysation) are generally more desirable for flavorings and
larger peptides for foaming agents and emulsifiers (Kristinsson
and Rasco, 2000; ˇ
Sliˇ
zyt˙
e 2009). The effect that various condi-
tions have on the size and character of final products of some
fish hydrolysates and their uses is outlined by Bourseau et al.
(2009), Cancre et al. (1999), Kristinsson and Rasco (2000),
Thorkelsson and Kristinsson (2009) and Kim and Mendis
(2006). Human health benefits of fish peptides are generally
attributed to high antioxidative properties (Dong et al., 2008)
and are given by He et al. (2007), Hong and Secombes (2009),
Je et al. (2004), and Marchbank et al. (2009) among others.
Methods of filtration and separation for purifying hydrolysates
are given by Bourseau et al. (2009), Vandanjon et al. (2009),
and Thorkelsson and Kristinsson (2009).
There are many publications which investigate the feasibil-
ity of feeding hydrolysates from fish and seafood coproducts to
fin-fish aquaculture species (Gildberg et al., 1995; Hevrøy et al.,
2005; Aksnes et al., 2006) among others and shrimp (C´
ordova-
Murueta and Garc´
ıa-Carre˜
no, 2002) with varying success. This
poses many opportunities for value addition, but strict biosecu-
rity and traceability measures would be necessary. Salmon hy-
drolysates and protein concentrates are already produced com-
mercially in conjunction with oils, by the companies mentioned
above, for use in the animal feed industry.
Carotenoids (Astaxanthin and Canthaxanthin)
Shrimp and salmonid coproducts also contains significant
amounts of carotenoid, mostly astaxanthin or canthaxanthin at
around 24 g per ton in cultured P. monodon (Babu et al., 2008)
and up to 7.5 g per ton in salmon viscera (Czeczuga et al., 2005).
Carotenoids are powerful antioxidants and, therefore, have many
beneficial properties in human and animal nutrition (Lorenz
and Cysewski, 2000; Pacheco et al., 2009). It is also used as a
pigment in cosmetics (Armenta and Guerrero-Legarreta, 2009).
Synthetic astaxanthin is used as a pigment in animal
feeds, particularly for salmonids (Lorenz and Cysewski, 2000;
Sachindra et al., 2006) at about 5 kg per ton (Synowiecki and
Al-Khateeb, 2003) as flesh color is important for salmonid mar-
keting. However, no significant difference was found between
uptake and deposition of synthetic astaxanthin and natural astax-
anthin in salmonid feeds (Lorenz and Cysewski, 2000). There-
fore, natural astaxanthin has no advantage within aquafeeds and
is unlikely to be able to compete with synthetic ingredients, al-
though there could be a niche in the organic aquafeed market.
However, concentrations are far less than in the alga Haema-
tococcus pluvialis, which commercially grown can contain as
much as 30 kg per ton (Guerin et al., 2003). Therefore, extrac-
tion of astaxanthin from shrimp and salmonid coproducts is only
likely to be cost-effective if it is removed during the processing
of other valuable products, but it may be able to add value to
salmon oil health supplements if retained during the extraction
process.
Extraction can be combined with chitosan production
(Armenta-L´
opez et al., 2002) and some studies have shown that
acids, commonly used in the chitosan industry, may increase
the yield of astaxanthin because of reduced oxidation. However,
excessively aggressive acid and alkali treatments can adversely
affect the carotenoid (Armenta-L´
opez et al., 2002; Sachindra
and Mahendrakar, 2005; Sachindra et al., 2006; Pacheco et al.,
2009). Most promising methods, both economically and envi-
ronmentally, therefore, are those which can combine mineral,
chitin, protein, oil, and carotenoid separation and extraction in
the various processes outlined above (Armenta-L´
opez et al.,
2002; Synowiecki and Al-Khateeb, 2003; Coward-Kelly et al.,
2006; Pacheco et al., 2009).
Natural astaxanthin of 60 capsules containing around 4 mg
from H. pluvialis commonly sell for around US$20 on the In-
ternet, therefore there is commercial potential for natural sub-
stance from a number of aquaculture sources including shrimp
and salmon coproduct.
CONCLUSIONS
Aquaculture coproducts are under-utilized in many parts of
Europe resulting in lost profits and potential environmental im-
pact through waste disposal. In Asia, coproducts are used for
production of value-added commodities but probably not to
their full economic potential. In addition, their current utiliza-
tion could be posing risks to the environment, human health,
and biosecurity.
Aquaculture coproducts have the potential to supply quality
fishmeal and oils to terrestrial livestock feeds, thus alleviating
some of the pressure on the reduction industries. They may
also be directed toward food additives, high-value health sup-
plements, and cosmetic industries that are acceptable to most
religious groups, in some cases providing a lucrative side in-
dustry. They have significant advantages over capture fishery
coproducts in that they can be supplied fresh and in a consistent
form. However, for many, further research is needed to sup-
port medical claims and develop markets for their full economic
potential to be met.
With regard to aquaculture mortalities, ABPR has proven
a barrier in many circumstances. However, research has shown
that there are other uses for mortalities which have greater biose-
curity and are kinder to the environment, reducing impacts and
burdens on resources. These strategies may not only reduce costs
but provide income if logistical and legislative barriers are over-
come. More research is required to evaluate these different tech-
nologies for resource efficiency in economic and environmental
terms. There are many economic and environmental assessment
tools which could do this such as standard Cost Benefit Analy-
sis approaches in conjunction with Life Cycle Assessment and
other environmental impact modeling tools.
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PERSPECTIVES ON THE UTILIZATION OF AQUACULTURE COPRODUCT IN EUROPE AND ASIA 507
ACKNOWLEDGMENTS
This project forms part of the EU-funded SEAT Project3
(Sustaining Ethical Aquaculture Trade). The authors would like
to thank the staff of Kasetsart University, Thailand, and Can
Tho University, Vietnam departments of fisheries SEAT project
teams for help in organizing field trips to aquaculture and pro-
cessing facilities, data collection, translation, and understanding
of the Asian situation.
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