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A New Generation of Feed Stock: Evidence That Microalgae Serve as High-quality, Sustainable Alternative Feed Protein
X. G. Lei
Professor of Molecular Nutrition
Department of Animal Science
Cornell University
Greatest Challenges of the 21st Century
•Food
•Energy
•Water
•Climate Change
Atmospheric Concentrations of CO2
Keeling et al., 2005
Food and Feed Security?
• Feeding 7 billion people, to 9
billion in 2030:
– 815 million hungry
– 2 billion at hidden hunger
– 1.2 billion at water scarcity
• Feeding: >50 billion animals:
– 18% calories, 25% protein (40 kg)
– 70-80% increase by 2050
– 75% land & 30% water for agric.
Global Feed Protein Crisis
• Total feed: 6 billion tons of dry matter
• Dependence on soybean meal:
– USA, 71% total
– China, 57% total, 17% self-sufficiency
– EU, 64% total, < 1/3 self-production
• Ban on meat and bone meal (50 mt off)
• Expansion of aquaculture/overfishing
• Pressure to lower feed/food competition
• Need: Alternative feed protein
Microalgae:
the Solution to Both Problems?
Research at Cornell
USDA/DOE Development Grant
• Feasibility
▫ microalgal biomass replace SBM/corn
▫ pigs, broilers, and layer hens
• Maximum % microalgae in diets
• Effects
▫ growth performance, health, and products
• Benefits and limits
• Microalgal species
▫ selection, culture, and processing
Are Microalgae Palatable?
A partial replacement of soybean meal by whole or defatted algal meal in
diet for weanling pigs does not affect their plasma biochemical indicators
• No effect on ADFI
– Defatted diatom
• 6.8 to 15%
– Full-fat diatom
• 7.2 to 12%
– Green algae 1
• 10 to 25%
– Green algae 2
• 7.5 to 21%
Microalgal Research at Cornell
Species Trials Animals
Broilers 10 1,938
Layers 10 630
Pigs 6 219
Mice
Total
13
33
380
3,167
In vitro n
Drop (-) Add (+)
SBM Amino acids
Corn Oil
Salt Acids
Limestone Enzymes
Phosphate Trace minerals
Time = 3 to 15 weeksHaematococcus pluvialis
Nannochloropsis oceanica
Desmodesmus sp (Green)
Staurosira sp (Diatom)
Nutritional Values of Microalgae as Animal Feed Protein
• Crude protein: • 5 types: 14, 19, 31, 38, and 43%
• Soybean meal (SBM): 44-48%
• Corn: 7-9%
• Fish Meal: 65%
• Digestibility: 70-90%
• Replacement:• Pigs: 7.5 to 15%, 5-8%SBM
• Broilers: 7.5 to 21%, 2 to 10%SBM
• Layers: 7.5 to 25%, 2 to 15% SBM
• )
2,263 million acres total, 19% cropland, corn 90% as feed
Table 1. Potential saving of corn and soybean meal and harvestable land in the U.S. with
microalgal inclusion into swine and poultry diets1
Dietary algae inclusion Corn/Soybean saved
thousand ton
Land saved
thousand hectares
5% 575 188-283
10% 1,150 375-567
20% 2,300 750-1,134
1Calculations based on the 1997/1999 yields from Bruinsma et al., 2003.
Is Algal Biomass Nutritious?
0
200
400
600
800
1000
1200
DM CP EE ADF NDF Lys Met Thr Trp Ca P Ash
% R
elat
ive
to S
oyb
ean DFA
FFADGA-1DGA-2
Dry matter: retention/digestibility: —/—Nitrogen retention/digestibility: —/—Inorganic phosphorus retention/digestibility: ↑/↓
2-16% DGA-2 (Gatrell et al., 2018)
AA retention: 70% (Control) vs. 76% (DGA-1) vs. 76%(WFA) —AA digestibility: 82% (Control) vs. 91% (DGA-1) vs. 88% (WFA) ↑
25% DGA-1/ 11.7%WFA (Ekmay et al., 2015)
Dry matter digestibility: 76% vs. 85% ↑Amino acids digestibility:
ASP, GLC, SER, GLY, ARG, ALA, TYR, VAL, PHE, ILE, LEU, LYS: ↑GLN: —
7.5-15% DFA (Manor et al., 2017)
Dry matter: retention/digestibility: ↓/ —Nitrogen retention/digestibility: —/—Ether extract retention/digestibility:↑/—Amino acid digestibility: ↓/↓
10% DGA-3 (Sun et al., 2016)
Broiler
Layer
Pig
Impact on Nutrient Digestibility & Retention
Down: ALT, uric acidSame: AKP, cholesterol, triglyceride, NEFA (Austic et al., 2013)
Same: amino acid, uric acid(Ekmay et al., 2014)
Same: plasma protein, uric acid (Gatrell et al., 2018)
DFA
DGA-1
DGA-2
Down: uric acid, Same: AKP, ALT, cholesterol, glucose(Leng, et al,. 2014)
Down: 3-MH, TRAPSame: AKP, corticosterone, glutamine, insulin, P, uric acid(Ekmay et al., 2015; Kim et al., 2016)
DFA
Down: 3-MH, TRAP, AKPSame: corticosterone, glutamine, insulin, P, uric acid(Ekmay et al., 2015; Kim et al., 2016)
WFA
DGA-1
Same: AKP, phosphorus, cholesterol, triglyceride, uric acid (Kim et al., 2016)
DGA-2
Same: Urea nitrogen(Manor et al., 2017)
Up: AKPDown: Urea nitrogenSame: TRAP, ALT amino acid, uric acid (Manor et al., 2017)
DGA-3
DGA-1
Broiler Layer Pig
Impact on Blood Measures
Impacts on Protease Activity in Digesta and Brush Borders
Digesta
Inte
stin
e
Protease Activity
Protease Activity
Dud
.
Juj
.
Ile.
H
H
H
25% DG1
11.7% DF
B
H
25% DG1Dud
.Juj.
Ile.
H
H
H
11.7% DF
11.7% DF
DG1; Desmodesmus spp. FD; Staurosira spp
DG2; Nannochloropsis oceanicaH
B
25% DG1
25% DG1 &
11.7 FD
H
H,B
DG2
Liver Muscle Amino acid
transporters
Cat1
pept1
H
Inte
stin
e
Lat1H
25% DG 1
AMPK
mTOR
P70
S6
EIF4E
Protein Synthesis
P
PS6& PS6: S6 25% DG1 H
S
6 8% DG2
B
11.7% DF HB
BB
AMPK
mTOR
P70 EIF4E
S6P
Protein Synthesis
B
2% DG2
B
4% DG2
B
B
PS6:
S6 4-8% DG2B
4-8% DG2
B
DG1 ; Desmodesmus spp.
FD; Staurosira spp.DG 2; Nannochloropsis oceanica
B
B B
B
Impacts on Amino Acid Transporters and Protein Synthesis Signaling
Impacts on Egg Albumin, Broiler Muscle and Pig Lean Mass
11.7% DF Egg weight
Egg albumin weight/height
25% DG+
protease Yolk weight
2-16 %DG
Breast dry matter
Breast crud protein
Breast relative weight
Percent body lean mass
Roles and Synthesis of EPA/DHAOmega-3 Fatty Acids (n3)
C18:3n-3Α-Linolenic acid (ALA)
C20:5n-3Eicosapentaenoic acid (EPA)
C22:6n-3Docosahexaenoic acid (DHA)
EicosanoidsAnti-inflammatory
Fish oils
• Increased EPA and DHA intakes are linked to Decreased:
• CVD, diabetes, etc
(Simopoulos, 1999 and 2002) 18
Human Nutrition of EPA/DHA
• De novo FA synthesis is low in mammals
• Western diet is low in ω-3 fatty acids
– Ideal ω6:ω3 ratio is 1
– US consumption is ~15-20:1
• Recommended: 200-400 mg EPA+DHA/day
– US: ~100 mg EPA+DHA/day
– > 5 times less in non-fish eaters
(Simopoulos, A.P., 2002; Smet, 2012)
What can we do about this deficiency?
Dietary Sources of DHA and EPA
• Fish/fish oil: availability, oxidation, and flavor
• Flaxseed/oil: largely ALA
• Terrestrial meat is low in PUFA
• Average American consumes:
– 40 kg broiler chicken/year
– 250 chicken eggs/year
– Relatively high in ω-6 and low in ω-3 fatty acids
(USDA Economic Research Service, 2016)20
Marine Microalgal Biomass• Defatted biomass (DFA) from biofuel
production research
– Residual long chain n3 fatty acids
– High protein content (44%)
• Moderate levels of inclusion have no effect on growth performance and digestibility
(Austic et al., 2013, Gatrell et al., 2014)
Enrichment of n-3 Fatty Acids in Breast and Thigh
Breast Thigh
Gatrell et al., 2015
Summary of Broiler Study
• Omega-3 content and ω6:ω3 ratios were improved at all levels of microalgal biomass inclusion.
• Consuming 200 g of chicken breast/day can supplement up to 35 mg of EPA/DHA.
0
10
20
30
40
50
60
L* a* b*
Co
lor
Val
ue
Color Value
0% 2.85% 5.75% 11.5% 23%Algae
Effects of Dietary Microalgae on Yolk Color
24
P-Value ≤ 0.0001dc c
b
a
a
b cd d
b b b ba
(Darker) (redder) (Bluer)
y = 0.16x + 1.95R² = 0.94
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 5 10 15 20 25
mg
/g s
amp
le
Algae (%)
P ≤ 0.0001
Yolk EPA + DHA
25
3-Fold
Yolk ω6:ω3
26
y = -0.36x + 11.5R² = 0.65
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
0 5 10 15 20 25
mg
/g s
amp
le
Algae (%)
P = 0.0004
3-Fold
Summary of Laying Hen Study
• Defatted microalgae enriched egg yolk with EPA and
DHA and decreased ω6:ω3 ratios in the yolk.
• Liver, breast, and thigh also had increased levels of
EPA and DHA.
• Microalgae affected expression of key genes involved
in EPA/DHA metabolism.
Regulation of Hepatic EPA/DHA
Synthesis by Microalgae
28
2
2
5
ACOT4
Elongase3Elongase4Malic Enzyme
Recent Progress
• Feeding DHA-enriched microalgae:
– > 200 mg/egg
– 80-100 mg/100 g fresh muscle tissue
• Effects of corn oil, Se, and vitamin E
• Regulation of P450 enzyme genes
• Enhancing enrichment
• Amount: 1 egg + 100 g chicken = 300 mg DHA
• Flavor: no difference
• Bioavailability: mouse study
• Health benefits: ?
Just Eat Chicken & Eggs for EPA/DHA
Enrichment of Astaxanthin in Egg Yolk
Magnuson et al., 2018
Microalgae as a Dual Source of Protein and Iron
• Contained > 2,600 mg Fe/kg
• Anemic pig model
• 0.5% was effective
• 15% was safe
• Fe deficiency affects 30-40% global population
Take-Home Message
• Microalgae can become an excellent source of feed protein.
• Microalgae can help enrich n-3 fatty acids in chicken and eggs.
• Microalgae can serve as a dual source of protein and micronutrients (Fe and phytochemicals).
Acknowledgements
• USDA/DOE Biomass R&D Initiative
Grant
• Cornell Hatch grants
• MAGIC grant (DOE)
• Heliae, DSM, Cellana
• Kreher Farms