This article discusses alternative protein sources for use in aquafeeds. It notes that alternative sources should demonstrate functionality to play a role in modern aquafeeds. Single-celled proteins like microalgae, bacteria and yeast are now being considered as attractive alternatives to traditional plant proteins. Yeast in particular has been thoroughly investigated as a protein source and fishmeal replacement because it is rich in protein and amino acids. The processing of these alternative proteins is important to provide the required nutritional functionality.

1. March | April 2010
Feature title: Protein sources - Alternative protein sources
should also show functionality if they are to play a role in modern aquafeeds
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2. F: Protein F: Protein
the EU noted that mycotoxins
accounted for 56 percent of
border rejections when identi-
fied by risk. This concern may
become increasingly important
© Mjunsworth | Dreamstime.com
in aquafeed formulations in the
future.
Protein sources
A number of production tech-
niques and specific products are
used to help reduce the effect
of anti-nutritional substances and
"The primary defence mechanism of a fish can be considered to be the physical
Alternative protein sources should also show mycotoxins in terrestrial animal
production, but these are not
barrier (skin, gills and gastrointestinal tract). Both externally and internally, therefore,
the mucosal barrier and tissue cellular membrane integrity play a vital role"
functionality if they are to play a role in
widely used in the aquaculture
sector at this time. Studies using
enzymes and mycotoxin adsorb-
modern aquafeeds ents are being carried out to find alterna-
tives to overcome these limitations.
Fermentation technologies may be used
to produce sustainable sources of single-
are a source of dietary nucleotides, which
have been shown to promote growth and
celled proteins: algae and yeast being two enhance non-specific immune activity. They
by Keith Filer Ph.D, research Manager, Asia-Pacific biosciences Centre, Alltech, inc. Single-celled proteins examples. are also low in phosphorous, which can lead
Single-celled proteins such as micro- Yeast based proteins have been the most to less water and environmental contamina-
algae, bacteria and yeast are now being thoroughly investigated as protein sources tion than fishmeal and other plant based
T
considered as attractive alternatives to and as a dietary replacement for fishmeal alternative protein sources that contain
he aquaculture industry Further formulation trends are moving meeting the nutritional requirement of the the more traditional plant protein sources. because they are a rich source of protein, high levels of this mineral.
today faces a number of towards low fishmeal and oil content in the animal being cultured. Many of these have been incorporated into with a relatively good balance of essential The processing and extraction tech-
challenges that threaten grower feeds and finishing feeds designed aquafeed with differing degrees of success amino acids. They contain B complex vita- nologies of both cell wall material and yeast
to restrict its development to restore flesh quality parameters such as Alternative vegetable (Oliva-Teles and Goncalves, 2001). mins, pigments, complex carbohydrates and extract are critical in providing function-
and profitability. omega 3 fats, and fillet quality that are con- protein sources
sidered essential for the promotion of the Over the last two decades aquaculture
To live in harmony with consumer expec- product and its benefits for human health. research has focused on plant protein
tations of the highest possible standards of This strategy addresses to some extent sources such as grains, pulses and oilseeds
product quality and to do so in a sustainable the limited resources of fishmeal and fish oil. as they are generally widely available.
and environmentally responsible manner However, the use of soybean meal and
necessitates an innovative, coordinated and Expectations of sustainability other plant based protein sources such as
holistic approach within the aquaculture The only way to achieve the expecta- legume seeds, oilseed cakes, leaf meals, leaf
industry. tions of sustainability and replace or supple- protein concentrates and root tuber meals
The requirement for sustainability has ment fishmeal and fish oil in aquafeeds is to have been limited due to the presence of a
focused on the composition of the feed exploit alternative protein and lipid sources. wide variety of anti-nutritional substances
being used as one of the key parameters
determining the sustainability of production
The obvious and traditionally used alter-
natives are animal and plant protein sources.
in these products and their interaction
with the physiology of the animal resulting
It’s time for us to Brand and Create our own destiny.
of a particular species, particularly the fish- However, in Europe, and now increas- in depressed growth and feed efficiency,
meal and fish oil content and how it relates ingly in North America, consumers pre- mortality and abnormal intestinal morphol- Exploring opportunities in an industry with a bright future: Aquatic proteins
to overall feed conversion ratios. fer aquaculture products to have been
fed without the use
ogy and damage.
These substances act in different ways:
to feed a growing population
of animal by-products by affecting protein utilisation and digestion Primacy of science in aquaculture: Nutritional tools for modulating intestinal microbial ecology, health and performance
due in part to recent (e.g. protease inhibitors, tannins, lectins) by
2010: The year when aquaculture reaches the volume of capture and becomes the more relevant segment of the industry
health scares in the affecting mineral utilisation (e.g. phytate,
terrestrial animal sec- gossypol pigments, glucosinolates) antivita-
tor such as bovine mins and other miscellaneous substances
spongiform encepha- (e.g. phytoestrogens).
lopathy (BSE). The increasing use of plant protein
The search is on, sources is also raising new concerns about
therefore, for not only possible contamination by mould derived
the simple replacement mycotoxins.
of protein, but the provi- This risk is enhanced by the global 26th Annual International Animal Health and Nutrition Symposium
Figure 1: A comparison of typical essential amino acid
sion of functional nutri-
tion addressing both the
nature and trading of plant protein sourc-
es and the as yet little investigated impact
MAy 16 - 19 | LexINgtoN, KeNtucKy, uSA
(EAA) requirements for fish and the EAA profile of sustainability and flesh of different mycotoxins and their interac-
AquateTM For more information, or to request an invitation, contact your local Alltech representative, visit www.alltech.com/symposium or email us at symposium@alltech.com.
quality requirements tions in aquaculture species. In 2008, the
Delegates who are members of ARPAS and AAVSB will be able to earn CEUs.
of the industry while Rapid Alert System for Food and Feed in
210mmx147mm.indd 1 2/19/2010 11:47:51 AM
12 | InternatIonal AquAFeed | March-april 2010 March-april 2010 | InternatIonal AquAFeed | 13

3. F: Protein F: Protein
have a requirement for a well-balanced by the presence of retained in the fish flesh so indicating more
mixture of essential and non-essential bioactive substances effective treatment.
amino acids from which to construct their and the epidermal The combined effect of SPMP and
own protein tissues and, therefore, the migration of inflam- improved operational practises resulted
balance of essential amino acids in the diet matory cells and in reduced Chalimi resettlement follow-
is crucial. Aquate is a rich source of highly their secretions, may ing treatment, which was attributed to
digestible amino acids with a crude protein affect the establish- increased mucal production (Figure 5) and a
content of approximately 47 percent. ment and prolifera- general overall lower level of pressure from
The amino acid profile of Aquate tion of ectoparasitic all stages of total mobile lice.
closely matches the requirement for fish copepods, ciliates or Marine Harvest concluded that the Loch
(Figure 1) and contains docosahexaenoic monogenean (Jones, Sunart trials indicated that
Figure 3: Typical skin mucus development on salmon fed
acid (DHA) at approximately 33.8 percent AquateTM SPMP in Scotland (Wallace et al, 2009). 2001). • The SPMP diet produced more epi-
of its fat content. Furthermore, its nucle- Work at GIFAS dermal mucus than the control diet.
otide content provides functional nutri- monitored sea • The SPMP diets promoted better gut
ents that are present in the yeast extract lice development on juvenile salmon and integrity, which allowed better uptake
Aquate SPMP and
TM
component. Nucleotides are known to showed that after a seven week period of of SLICE® into the flesh of fish.
play a major role in almost all biologi- Atlantic salmon feeding the total sea lice counts showed • Using SPMP to enhance emamectin
cal processes and this includes: storage The primary defence mechanism of a that fish fed with the addition of Bio-Mos uptake was environmentally positive.
of energy, components of several coen- fish, exposed to an infectious or damaging had significantly lower overall numbers of • Using SPMP to encourage epidermal
zymes which are involved in carbohydrate, agent, can be considered to be the physical sea lice present compared with the fish mucus curbed Chalimi resettlement in
protein and fat metabolism, mediation barrier (skin, gills and gastrointestinal tract) fed the control diet. In addition, the total comparison with control populations.
in cellular processes, control of several and their protection mechanisms, at the number of individual salmon infected by • SPMP can be incorporated into the
Figure 2: Mucal production increases with the addition of enzymatic reactions and intermediates in point of interaction of the environment and sea lice (irrespective of species, life stage diet at the initial stage of food produc-
Bio-Mos® (Torrecillas et al, 2008). biosynthetic reactions. the physiology of the fish. Both externally or sex) was significantly reduced by the tion, thus eliminating an additional
Aquate’s level of nucleotides ranges and internally, therefore, the mucosal bar- Bio-Mos supplementation (Table 1). cost for top coating.
from five percent to as much as 15 percent rier and tissue cellular membrane integrity In the United Kingdom, the aim of the In Norway, Salmon Group, following
ality and optimising nutritional potential and feed industry or for the extrac- in the specialised AquateTM Junior product. play a vital role in this process. National Sea Lice Strategy is to extend the industrial trials using SPMP, concluded that
by ensuring a high degree of digestibil- tion of high-valued components such Aquate Junior has been designed for juve- In sea bass (Dicentrarchus labrax), mucosal lice free period
ity. Industrial spray drying techniques have as vitamins (C & D2), n-fatty acids, nile stages of aquaculture species, where production increases when Bio-Mos is fed and reduce
played a significant role in improving these pigments and antioxidants (B carotene, a rich source of nucleotides are especially as indicated by the significant increase the frequency
characteristics. astaxanthin, lutein). important for immunity and gut health. (P<0.05) in the number of cells secreting of therapeutic
Microalgae are rich sources of protein,
carbohydrates and lipids.
Through the careful formulation and
blending of algal and yeast components
The Aquate family has been designed
to provide functionality in aquafeeds
acid mucin in the posterior gut (Figure 2).
The quantity of lysozyme in the mucus was
intervention.
M a r i n e
Marine phospholipids
The amino acid profile of almost all Alltech has produced the AquateTM to meet the specific requirements of a also increased. Harvest sam-
algae compares favourably to other food range of products designed to provide particular aquaculture sector or species. In commercial field studies carried out pled fish muscle A new generation of omega-3 lipids
protein sources and the carbohydrate nutritional solutions for the aquaculture AquateTM SPMP also contains the specific by Marine Harvest in 2008 (Wallace et al, for emamectin
with a broader spectrum of health
components are highly digestible. industry. yeast cell wall component Bio-Mos®, which 2009) salmon fed on Aquate SPMP showed benzoate
However, it is the lipid content that is Aquate is the commercial name for a has been used to provide an effec- increased skin mucous secretion (Figure 3). (EmB) in fish bene ts.
especially interesting because of the func- second generation of sustainable product tive feed component in the fight to This increased skin mucosa was character- fed Aquate
tionality of this component, particularly solutions aimed at enhancing biomass control sea lice in salmonid culture. ised in the field by noticeably more slimy SPMP and the - High DHA contents, preferably in
so in some species rich in n-3 and n-6 production, feed efficiency and boosting Combinations of functional nutrition in fish and was also widely reported by site control diets easily digestible and highly bio
fatty acids. natural defence mechanisms in aquacul- this manner has resulted in improve- managers from Salmon Group in Norway. immediately available form for aquaculture use.
Today, commercial microalgae produc- ture species so encouraging healthier and ments in gut morphology, nutrient The role of mucus in anti-parasitic after the end
tion is used to produce algal biomass for more robust populations. uptake, improved immuno-competence mechanisms in fish is not well under- of medication - Numerous bene ts on improving
direct use as feed additives in the food Aquaculture species, like other animals, and disease resistance. stood. Buchmann and Bresciani (1998) with SLICE®. the immune response, better
demonstrated that mucus, as measured Noticeably weight gain and physical
by the density of mucous cells, could higher levels of
Table 1: the number of sea lice found to be present on sampled juvenile salmon. conditions of land animals.
play a role in limiting the parasite load the medicinal
Control CAGES BIo-MoS CAGES of monogeans in rainbow trout. Other residue were
authors have shown that monogenean found in the
1 2 3 4 AVERAGE 1 2 3 4 AVERAGE T-TEST
and crustacean ectoparasites can modu- fish fed Aquate
late mucus production during attach- SPMP (Figure
ment by reducing the mucous cells in 4). This is
Mature
1 2 0 1 1 0 0 1 1 0.5 0.178 the skin of the host (Wells & Cone 1990, important envi-
females
Nolan et al 1999). ronmentally as
Preadult 14 32 24 53 30.75 29 24 15 20 22 0.179 Recent studies, however, have begun to less emamec- Fiskerihavnsgade 35 Phone +45 79120999
Chalimus 22 4 8 26 15 8 8 14 7 9.25 0.170 clarify the relative roles of the immune system tin benzoate P.O. Box 359 Fax +45 79120888
in fighting parasitic infections in fish. It has is voided in
Caligus 17 14 14 5 12.5 8 14 7 5 8.5 0.140 6701 Esbjerg E-mail 999@999.dk
been suggested that the physico-chemical the faeces
Denmark Web www.999.dk
TOTAL 54 52 46 85 59.25 45 46 37 34 40.5 0.044 characteristics of skin mucus as determined and more is
14 | InternatIonal AquAFeed | March-april 2010 March-april 2010 | InternatIonal AquAFeed | 15
999_AD_IAF0904V3.indd 1 22/06/2009 14:01

4. F: Protein
canadum), Chou et al,
2004 reported that a 40
percent replacement of
fishmeal with soybean
conversion ratio, led Virginia Cobia Farms
to consider the inclusion of Aquate in their
proprietary cobia grow-out formulations.
in the Family
meal did not have a neg- Conclusion
ative effect on growth Single-celled protein sources have the Alltech® has developed a range of products to address dietary requirements at different
performance, but that potential to become a renewable source of
at higher replacement functional nutrition providing both alterna- stages of life in aquaculture species. These sustainable product solutions are proven to
rates growth perform- tives to fishmeal and fish oil. support profitability in aquaculture operations as well as performance in fish and shrimp.
ance decreased.
A recent trial at References
™
Virginia Cobia Farms
Buchmann K & Bresciani J (1998).
in Saltville, Virginia, USA Microenvironment of Gyrodactylus derjavini on
investigated the poten- rainbow trout Oncorhynchus mykiss: association Ideally suited for fish and shrimp in any stage of life to maintain performance and to
Figure 4: EmB residues in the SPMP study in Loch Sunart
(Wallace et al, 2009).
tial of Aquate inclusion between mucous cell density on skin and site support independence from traditional aquaculture diet ingredients.
(30 percent of the dry selection. Parisitology Research 84, 17-24.
diet) to replace fish- ™
Chou RL, Her BY, Su MS, Hwang G, Wu
meal and fish oil for the YH & Chen HY (2004). Substituting fishmeal
marine carnivore cobia with soybean meal in diets of juvenile cobia
Racyhycentron canadum. Rachycentron canadum. Aquaculture 229, 325- Specifically designed for the juvenile stages of life in fish and shrimp to support good
The high level of 333. health, uniform growth and survival.
replacement of fishmeal
Jones SRM (2001). The occurrence and
was designed to capital- ™
mechanisms of innate immunity against parasites
ise on the DHA content in fish. Developmental and Comparative
of Aquate and investigate Immunology 25, 841-852.
if it could not only satisfy A natural, affordable product created for salmon in all life stages to maintain good
04/01/2008
18/01/2008
01/02/2008
15/02/2008
29/02/2008
14/03/2008
28/03/2008
11/04/2008
25/04/2008
09/05/2008
23/05/2008
Nolan DT, Reilly P & Wendelaar Bonga SE
the essential fatty acid health and defense mechanisms against adverse aquatic elements present in the
(1999). Infection with low numbers of sea louse
requirements of juvenile
Lepeoptheirus salmonis induces stress-related surrounding environment.
cobia, but also provide
effects in post smolt Atlantic salmon (Salmo salar).
Figure 5: Average Chalimi levels from SPMP fed fish adequate n-3 HUFA in
versus controls, Loch Sunart. (Wallace et al, 2009) Can J. Fish Aquatic Sci. 56, 947-959.
the final product for Give your fish and shrimp the Alltech Aqua Advantage.
human consumers. Oliva-Teles, A. & P. Goncalves. 2001. Partial
replacement of fishmeal by brewers yeast Contact your Alltech representative today
A commercial diet
regularly used for cobia
(Saccaromyces cerevisiae) in diets for sea bass for more information.
(Dicentrarchus labrax) juveniles. Aquaculture 202,
production was used as 269-278.
the control diet and a
"Single-celled protein sources have the second experimental Torrecillas S, Makol A., Caballero M.J, Montero D,
Sweetman J & Izquierdo M.S (2008). Enhanced
potential to become a renewable source diet high in soy product
nutrient utilization and bacterial infection
inclusion (>55 percent
of functional nutrition providing both of the dry diet) was also
resistance in European sea bass (Dicentrarchus
labrax) fed mannan oligosaccharides. Poster
included. At the end
alternatives to fishmeal and fish oil" of the feeding trial, the
presented at XIII ISFNF Meeting, Brazil 1-5 June.
fish were harvested and Wallace C, Waddell R, Cockerill D & Ritchie
G (2009). Double mucal effect boosts sea lice
utilized for test market-
control and potentially extends useful life of
ing purposes in which
medications. Fish Farming Xpert, No 1/09, 48-53.
• 4/5 farms reported better general chefs, distributors and others compared
health status in the SPMP fed fish. the cobia fed the experimental diets in Wells PR, & Cone DK (1990). Experimental
• 4/5 farms reported less lice treat- terms of taste, texture, physical and visual studies on the effect of Gyrodactylus
ments in the trial fish. preferences. colemanensis and G. salmonis on density
of mucous cells in the epidermis of fry of
• All farms reported that the fish The trial showed that Aquate could be
Oncorhynchus mykiss. J. Fish Biol. 37, 599-603.
appeared to be very slimy. used as a partial provider of essential n-3
HUFA in marine fish diets and
Aquate trial with cobia that the inclusion of Aquate
In omnivores and herbivorous species, appeared to impart beneficial More inforMation:
such as catfish or tilapia, high replacement taste and texture characteristics Keith Filer Ph.D
levels (>40 percent) of fishmeal can be to the final product with 83 Research Manager
tolerated provided that the amino acid percent of the test panel prefer- Asia-Pacific Biosciences
Centre
requirement of the fish species is met ring the Aquate fed fish to that of
Alltech, Inc.
from other sources. However, in the car- the high soy inclusion diet. This, Email: kfiler@alltech.com
aquasolutions@alltech.com
nivorous fish species cobia (Racyhycentron combined with an improved feed www.alltech.com
16 | InternatIonal AquAFeed | March-april 2010

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