Feed for fish and shrimp raised in aquaculture needs high levels of protein and energy. Traditionally feed for carnivorous or omnivorous fish and for shrimp provides these mainly as fishmeal and fish oil, which also contributes to the health promoting aspects of fish and shrimp in the human diet.
2. FEATURE
Options and challenges of alternative protein
and energy resources for aquafeed
by Dr Alex Obach, Managing Director, Skretting Aquaculture Research Centre, Norway
F
eed for fish and shrimp raised in Rising demand welfare and produce fish that are good
aquaculture needs high levels of Analyses of global demographics, widely to eat, both in terms of eating experience
protein and energy. Traditionally publicised by the Food and Agriculture and nutrition. It has been a main focus at
feed for carnivorous or omnivo- Organization of the United Nations (FAO), Skretting Aquaculture Research Centre for
rous fish and for shrimp provides these indicate a continuing expansion of the popu- the past decade, for example determining
mainly as fishmeal and fish oil, which lation passing nine billion by 2050. In parallel, the nutritional value of more than 400
also contributes to the health promoting economic development is providing a greater raw materials. These investigations led
aspects of fish and shrimp in the human proportion with an income that permits to AminoBalance™, where balancing of
diet. them to be more selective about their diet. amino acids increases the contribution
The main trend is to switch from vegetable such proteins make to muscle growth.
Aquaculture of fed species today takes staples to animal and fish protein. A third,
60–80 percent of the fishmeal and 80 per- but lesser, factor is the growing awareness Figure 1: Raw material options for fish
cent of the fish oil produced, mainly from of the health benefits of fish in the diet, feed (Source Skretting)
the industrial pelagic fisheries or, in a grow- providing long chain omega-3 polyun- Protein raw Starch
Fats
ing trend, from the trimmings produced saturated fatty acids (LC PUFAs) EPA materials sources
during processing for human consumption. and DHA, fish proteins and important
Trimmings are defined as by-products when vitamins and minerals such as iodine and Fish meal Fish oil Wheat
fish are processed for human consump- selenium.
Krill meal Krill oil Barley
tion or if whole fish is rejected because At the same time, a growing propor-
the quality at the time of landing does not tion of the pelagic catch, which includes algal meal algal oil Sorghum
meet requirements for human consump- the industrial fisheries, is going to the Soya products rapeseed oil tapioca
tion. The International Fishmeal and Fish more lucrative markets of processing for Sunflower meal Soybean oil Potato starch
Oil Organisation estimates trimmings are human consumption, as processing tech- rapeseed meal Sunflower oil Peas
now used for around 25 percent of fishmeal nology improves and as new consumers
Corn gluten Corn oil Faba beans
production. with different tastes enter the market.
Wheat gluten linseed oil oats
The industry is, therefore, heavily Simultaneously, the omega-3 supplements
dependent on marine resources but pro- industry is competing for the best qual- Faba beans Palm oil
duction from these resources cannot be ity fish oils and readily outbids the feed lupins Camelina oil
increased sustainably, either for human con- producers. Pea meal Poultry fat
sumption or the industrial fisheries. At best, According to the FAO report
rice products lard
sustainably managed fisheries will continue ‘The State of World Fisheries and
Poultry meal
to yield around the current harvest of five Aquaculture 2012’, aquaculture is “set
million tonnes of fishmeal and one million to remain one of the fastest grow- Feather meal
tonnes of fish oil. ing feed sectors”. Having doubled in Blood meal Marine origin
Feed producers such as Skretting require the past decade to almost 60 million Meat and Bone Vegetable raw
their marine raw material suppliers to tonnes globally, it is expected to grow meal materials
document that the fishmeal and fish oil are by up to 50 percent in the next. This Microbial
Animal
derived from responsibly managed and sus- makes identifying alternative, sustainable protein
by-products
tainable fisheries and do not include endan- sources of protein and energy a major Insect meal
gered species. Therefore, to meet a growing priority. Researchers are looking for Other raw
Worm meal
demand for fish, aquaculture must identify alternatives that will provide low feed materials
alternatives to these marine ingredients. conversion ratios, maintain high fish DDGS
22 | InternatIOnal AquAFeed | September-October 2012
3. FEATURE
Recent advance fish feed was approved by a qualified major- Atlantic salmon provided were divided and
Research progress to date means fishmeal ity of EU member states, meaning that non- fed on one of three feeds:
levels in feeds for species such as Atlantic ruminant PAPs will be authorised for fish feed Conventional grower feed (pre
salmon have been reduced. Until recently 25 from June 1, 2013. MicroBalance): 25 percent fishmeal and 13
percent appeared to be the limit below which percent fish oil with EPA + DHA comprising
performance suffered, in terms of growth rate Trial results about 10 percent of total fatty acids.
and feed conversion ratio. A 22-month trial with Atlantic salmon in OptiLine from Skretting Norway (using
In 2010 researchers at Skretting ARC final- a commercial scale farm in Norway dem- MicroBalance): 15 percent fishmeal and 13
ised a new concept known as MicroBalance™. onstrated the
MicroBalance™ technology is based on the practicality of
identification of several essential micro-nutri- MicroBalance. It
ents in fishmeal that were shown to be the followed a com-
limiting factors, not the amount of fishmeal. plete genera-
Supplementing the diet with the right bal- tion of salmon
ance of essential micro-nutrients and other from smolt to
functional micro-ingredients helped reduce harvest. The
fishmeal content in fish feed. trial was jointly
Applying the concept enabled Skretting organised by
companies to produce commercially success- Marine Harvest
ful feeds with as little as 15 percent fishmeal and Skretting
without detracting from feed performance, and conducted
fish welfare or end product quality. A key at the Centre
advantage of MicroBalance is the flexibil- for Aquaculture
ity to adapt the raw material combination in Competence
response to prices, lessening for farmers the (CAC) in
impacts of price volatility. Norway from
Today Skretting can formulate fish feed May 2009 to
with levels of fishmeal as low as 5–10 February 2011
percent. Fishmeal can be replaced solely by inclusive. CAC
vegetable raw materials or by a combination is a commercial-
of vegetable raw materials and non-ruminant scale R&D farm
processed animal proteins (PAPs). It should managed by
be noted that PAPs are widely used in coun- Marine Harvest
tries outside the EU and provide extremely and is equipped
good quality, safe nutrition to supplement to measure all
fishmeal. operational
Typical examples include blood meal also parameters just
known as haemoglobin meal, poultry meal, as precisely as
and feather meal. PAPs were banned from in a small-scale
animal feed and fish feed in the EU follow- research sta-
ing the BSE crisis in the 1990s. Recently a tion. A total
proposal for the reintroduction of PAPs in of 780,000
September-October 2012 | InternatIOnal AquAFeed | 23
4. FEATURE
example, following the introduction of the
MicroBalance concept, the fish oil will certainly
be the determining factor for the FFDR. The
dependency on wild forage fish resources
should be calculated for both FM and FO
using the following formulae.
FFDRm = (% fishmeal in feed from forage
fisheries) x (eFCR) / 22.2
FFDRo = (% fish oil in feed from forage
fisheries) x (eFCR) / 5.0
Where:
eFCR is the Economic Feed Conversion
Ratio; the quantity of feed used to produce
the quantity of fish harvested.
Only fishmeal and fish oil that is derived
Figure 2: Supply and use of fish oil (Source IFFO and Skretting)
directly from a pelagic fishery (e.g. anchoveta)
is to be included in the calculation of FFDR.
percent fish oil with EPA + DHA comprising and DHA, both for the fish and for the health The amount of fishmeal in the diet is calcu-
about 10 percent of total fatty acids. benefits of fish as food. lated back to live fish weight by using a yield
Experimental OptiLine (using Secondly the EU AquaMax project, coordi- of 22.2%. This is an assumed average yield. If
MicroBalance): 15 percent fishmeal and nine nated by NIFES in Norway with 32 international the yield is known to be different that figure
percent fish oil with EPA + DHA comprising partners around the world including Skretting should be used.
about eight percent of total fatty acids. ARC, addressed this issue directly, developing The amount of fish oil in the diet is calcu-
The parameters monitored were diets with low levels of both fishmeal and lated back to live fish weight by using a yield of
growth, FCR, quality, health, sustainability fish oil and thus reducing the fish-in fish-out five percent This is an assumed average yield.
and food safety. The total harvest weight ratios. This com-
was 3,517 tonnes. After the harvest the plements work table 1: total production of fed species in 2000, 2005, 2010, with total
taste, smell and texture of the fillets were at Skretting ARC feed used, total fishmeal and total fish oil (x 1,000 tonnes).
tested by a panel of professional tasters. to develop the Year total production total of feeds total fishmeal total fish oil
The results showed that both low fishmeal LipoBalance™ of fed species used used used
feeds gave the same growth and FCR as concept, which
the control diet. There were no observed allows combina-
1995 4,028 7,612 1,870 463
differences in fish health, or in the quality tions of oils to
parameters. be prepared that 2000 7,684 14,150 2,823 608
The salmon fed with the lowest propor- will provide the 2010 21,201 35,371 3,670 764
tion of marine products (15% fishmeal, 9% fish correct balance Source: Tacon et al. FAO Fisheries and Aquaculture Paper 564
oil) only needed 1.07 kg of fish in their feed of energy and
to produce 1 kg at harvest. Calculating protein nutrients, including EPA and DHA, at lowest If the yield is known to be different that figure
alone showed a positive ratio, with fish out cost. should be used.
exceeding fish in. Using these formulae it can be seen that
MicroBalance is now applied in the diets Performance ratios the FFDRs for Atlantic salmon, for example,
of several other commercial species, including Feed conversion ratios (FCRs) have were halved between 2004 and 2011. The
sea bass, sea bream, rainbow trout, turbot advanced significantly over the past three FFDRm was reduced from 1.24 to 0.56 and
and yellowtail. decades. In Atlantic salmon, for example, the the FFDRo from 4.28 to 2.05. This doubles
FCR has decreased from 1.30 in the 1980s the quantity of salmon produced from a given
Fish oil to slightly above 1.00 today, mainly due to quantity of fishmeal and fish oil.
Research to date has enabled produc- the development of high-nutrient-dense diets
ers of fish feed to supplement fish oil with and to improvements in feed management Health benefits
vegetable oils in the diets of carnivorous spe- (reducing feed waste). This represents more As mentioned, maintaining health benefits
cies by as much as 50 percent. Lower levels efficient use of feed raw materials; especially is a key objective when reducing dependency
have been tested in experimental diets with as fishmeal and fish oil contents were reduced on marine raw materials. It is being addressed
no negative effects. Much of the progress in the same period (Table 1). in several ways. The first is to determine the
results from the EU RAFOA project. RAFOA Another contributor here is the emer- minimum levels of EPA and DHA that the fish
stands for Researching Alternatives to Fish gence of functional diets that maintain or even require. The feeds with high levels of marine
Oil in Aquaculture and the project focused improve performance in adverse conditions ingredients produced fish with high levels of
on four species; Atlantic salmon, rainbow such as high or low water temperatures and long chain (LC) poly-unsaturated fatty acids
trout, sea bass and sea bream. Led by the outbreaks of disease. Better growth, reduced (PUFAs); more than needed by the fish so
Institute of Aquaculture at the University of FCR and higher survival will all contribute to that a proportion was metabolised for energy.
Stirling, partners include NIFES (the National improve the utilisation of feed resources. At lower inclusion levels the use of these lim-
Institute of Nutrition and Seafood Research) Feed Fish Dependency Ratio (FFDR) is ited nutrients can be optimised, since a higher
and Skretting ARC, in Norway, the INRA the quantity of wild fish used per quantity of proportion will be retained in the muscle. At
(National Institute for Agronomic Research) cultured fish produced. This measure can be even lower levels (close to nutritional require-
in France and the University of Las Palmas, weighted for fishmeal or fish oil, whichever ment) the fish can maximise its capacity to
in the Canary Islands (Spain). The main chal- component creates a larger burden of wild elongate and desaturate, and could become a
lenge is to maintain adequate levels of EPA fish in feed. In the case of Atlantic salmon for net producer of LC PUFAs.
24 | InternatIOnal AquAFeed | September-October 2012
5. FEATURE
On average 100 g of salmon fillet has Limited progress has been with EPA. DHA is
around 16 g of fat of which at least four to a greater challenge.
five percent is omega-3 EPA and DHA (DHA Some micro-algae species are natural syn-
being the main fatty acid in the phospholipid thesisers of the longer chain fatty acids. The
fraction). Thus a 130 g portion would provide challenge here is economic; to grow them
around 930 mg of EPA and DHA. That is in bulk, either by sea farming or in vats on
equivalent to several supplement capsules. land, in sufficient volumes to make them
Two portions a week adequately provide the competitive as a feed ingredient. There are
recommended dietary levels of LC PUFAs and also reports of extracting LC PUFAs from
important vitamins and minerals in an easily yeast cultures and these would face the same
assimilated form. economic challenge.
A second approach is to explore ways of
formulating feed so that the LC PUFAs are Conclusion About the author
retained in the fillet flesh. Further research at Aqua feed producers must find alterna- Alex Obach has held the position
Skretting ARC into the functions of micro- tives to the marine ingredients fishmeal and of Managing Director at Skretting
ingredients recently led to a new salmon feed fish oil while maintaining fish welfare and Aquaculture Research Centre since
that significantly improves the feed conversion aquaculture performance as a highly effi- May 1, 2007. Originally from Barcelona,
ratio and fillet yield. Fillet analysis revealed the cient means of producing nutritious protein. Spain, he is a veterinarian with a Master
in Aquaculture from the University
micro-nutrients also raised the proportion of Eating quality and health benefits are equally
of Girona (Spain) and a PhD in fish
EPA and DHA in the muscle. important.
pathology and immunology from the
The third approach is to identify alternative However, although the supply of marine University of West Brittany (France). He
resources. There are two major contenders: ingredients from the wild catch is limited, started working at Skretting Aquaculture
genetic modifications to crop plants and with appropriate controls they will continue Research Centre in 1993 as a research-
micro-algae. Progress is being monitored by to be available. A key task for the industry er, initially within fish health then as
feed producers keen to reduce their depend- is to ensure they are used in a manner that a nutritionist. He He previously was
ence on marine ingredients. Some plants spreads the benefits through a combination Manager of ARC’s Fish Health depart-
produce PUFAs, for example rape (canola) or of supplementation, feed formulation and ment. Between 1993-1995, he was also
soya, but the carbon chains are too short. The feed management on farm. This way the engaged as lecturer at the University of
EPA carbon chain has 20 carbon atoms and growing demand for fish can be met and the Barcelona, and worked for two years
as Manager of the Marine Harvest
DHA 22. The ambition is to introduce genes benefits shared sustainably for generations
Technical Centre.
to extend 18-carbon chains already present. to come.
September-October 2012 | InternatIOnal AquAFeed | 25
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