Microalgae – a potential fish feed resource? Margareth Øverland

Salmonid production, Norwegian and global

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1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

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Production and value of Atlantic salmon and rainbow trout

Norway World Value (Norway) Value (World)

Advantages

• Availability and supply • Environmental profile • Low cost

Disadvantages

• Low nutrient density • Unbalanced AA profile • Taste • Antinutrients • No EPA or DHA

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Potentials and challenges with plant ingredients

Fishmeal-free diets for salmonids

A: P-MIX1.0

B: C-MIX1.0

C: S-MIX1.0

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FCR

0.780

0.788

0.799

0.8170.832

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2 Feeding a combination of pea, potato and rapeseed protein gave similar growth performance as fishmeal

Feed efficiency

Source: APC, Zhang, 2012

Mixed model design Contour plot

Pea + potato

Soya Rapeseed +Potato

Bacteria Methylococcus capsulatus

Microbial ingredients in fish feeds Production

Yeast/Fungus Rhizopus oryzae

Many possible substrates: • Methane or methanol (e.g. natural gas or methane) • Co-products from forest industry and agriculture

- Lignocellulosic biomass • Sunlight + CO2

Microalgae Phaeodactylum, Chlorella,

Methylococcus capsulatus

Bacterial meal Value chain from natural gas to high-value feed resources for the production of human food

Bacterial meal (BM) is produced by aerobe fermentation: • Methanothroph bacteria and helper bacteria

• Methanol or Methane from natural gas

• Oxygen, ammonia, minerals

Crude protein (10% nucleic acids)

70%

Crude lipids (phospholipids) 10%

Carbohydrates 12%

Ash 7%

(Source: Øverland et al., 2011)

Growth (%/Day) and feed efficiency (Gain/Feed) of Atlantic salmon fed increasing levels of bacterial

meal

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Level of bacterial meal (%)

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Source: Aas et al. 2006

Production of yeast from forest industry Lignocellulosic biomass

Mechanical pretreatment

Thermo-chemical pretreatment

Enzymatic hydrolyzes

Fermentation

Cellulose

Growth (%/day) and feed utilization (feed:gain) of salmon fed 30% yeast

APC, 2012, Øverland et al., unpublished

a

FM Yeast 1 Yeast 2 Yeast 3

Gain, %/day Kg feed / kg gain

Microalgae in fish feed Chemical characteristic of microalgae

Microalgae is produced by: • Heterotrophic or autotrophic production

• Freshwater or saltwater

• Lipid, protein and carbohydrate composition varies with production conditions

Crude protein

20 - 40%

Crude lipids 5 - 60%

Carbohydrates

Minerals, vitamins, carotenoids

Microalgae Phaeodactylum, Chlorella

Reseach on Microalgae in APC

1. Evaluation of nutritional value of : Nannochloropsis oceania, produced at UMB Isochtysis galbana from, Reed Mariculture, USA Phaeodactylum tricornutum, Fitoplankton Marino, Spain

Collaboration among APC; UMB, SINTEF, and Nofima

2. Evaluation of functional properties of microalgae 3. Chemical profiling of microalga from heterotrophic production Production of Nannochloropsis

oceania at UMB

Collaboration between APC and Nofima

Source: APC, Skrede et al., unpublished

Chemical composition of microalgae, % Nannochloropsis

Oceania Isochrysis galbana

Phaeodactylum tricornutum

High-quality fishmeal

Crude protein, % 47.7 20.1 49.0 74.7

Crude fat, % 8.4 16.2 7.4 9.7

EPA, C20:5 2.3 0.08 2.8 1.5-2.0

DHA, C22:6 - 1.6 0.02 0.7-1.3

Amino acids, g/16 g N

Lysine 4.8 3.1 4.2 6.8 Methionine 1.8 2.5 2.0 2.5

Tryptophan 1.7 2.5 1.3 0.7

Threonine 3.6 4.6 3.7 3.5

Valine 4.6 6.1 4.6 4.0

Isoleucine 3.5 5.1 3.8 3.7

Leucine 6.7 9.2 6.2 6.2

Phenylalanine 3.9 5.7 4.2 3.3

Arginine 4.9 4.1 4.4 5.4

Apparent crude protein digestibility of the algae products

Nannochloropsis

y = -0,5233x + 87,844R2 = 0,9966

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Phaeodactylum tricornutum

y = -0,0777x + 87,639R2 = 0,9853

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Isochrysis galbana

y = -0,69x + 87,806R2 = 0,9928

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The protein digestibility of the algae when extrapolating to 100% of protein from algae were: Phaeodactylum tricornutum: 79.9% Nannochloropsis oceania : 35.5% Isochrysis galbana : 18.8%

Apparent amino acid digestibility of LT fishmeal and the three algae products

N. Oceania

P. Tricornutum

I. galbana

LT fishmeal

Arg 41.2 87.4 56.8 93.6

His 17.2 76.6 37.1 88.9

Ile 30.3 75.9 63.5 92.4

Leu 30.9 81.6 68.6 93.0

Lys 38.1 84.5 12.6 86.8

Met 35.6 83.4 64.8 93.5

Trp 38.3 81.7 69.0 85.6

Phe 31.9 83.2 69.2 90.3

Thr 50.1 83.0 55.0 85.0

Val 31.6 82.2 62.5 91.4

Apparent crude fat digestibility of the algae products

Although the algae products represented a minor proportion of total dietary lipids some indications were observed: All algae products gave a reduction in lipid digestibility with increasing inclusion of algae lipids. Calculation of the digestibility of lipids in the algae products would result in negative digestibility.

Nannochloropsis

y = -0,5587x2 + 0,2459x + 98,032R2 = 0,9998

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Phaeodactylum tricornutum

y = -0,1732x2 - 0,2497x + 98,107R2 = 1

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Isochrysis galbana

y = -0,0746x2 - 0,1763x + 98,186R2 = 0,9988

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Functional properites in microalgae

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Hypotheses: Certain microalgae may have beneficial health effects Soybean meal was used as a model to study gut health Feeding soybean meal results in: Enteritis in the distal intestine

Reduced feed intake, growth, and digestibility

Reduced enzyme activity and bile salt levels in the intestine

A: Fiskemel

B: Soyamel

Normal gut

Soy-induced enteritis

Foto: T. Landsverk

Microalgae in feed containing 20% SBM Degree of inflammation in distal intestine

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SBM (Pos. ctrl.) FM (Neg. ctrl.) ALG (SBM + alga)

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Diet

Leukocytes in Lamina PropriaEpithelial changesAtrophyOedema

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* = different from SBM at p<0.01+ = different from FM at p<0.01

APC, 2012, unpublished

Feed, % FM SBM ALG

Fishmeal 71 51 29.5 Soybean meal 0 20 20

Microalgae - - 20

Conclusion - 1

• Microbes represent very promising feed ingredients

• They are sustainable feed resources - they do not require agricultural land, use little water (or recycling) and can be made from non-food raw materials

• Micro algae have some limitation concerning opening up the cell-walls and low digestibility of nutrients in several species

• Some microbes (both bacteria, yeast and microalgae) contain many interesting bioactive components that can give positive health effects

• The positive health effects are very species (and possibly also strain) specific

Conclusion - 2

• To be successful, microbial ingredients must have a high nutritional value (omega 3)/health benefits and be produced economically

• Revisions of EU regulations on microbial protein sources (Regulation (EC) No 767/2009) will facilitate further development and use of such products as feed ingredients