An overview of lipid nutrition with emphasis on alternative lipid sources in

tilapia feeds

Wing-Keong Ng & Cheong-Yew Chong

Fish Nutrition LaboratorySchool of Biological Sciences

Universiti Sains MalaysiaPenang, Malaysia

Tilapia aquaculture is one of the fastest growing industry in the world.

With increasing intensification of culture systems, complete formulated feeds are required.

Feed Cost versus Tilapia Prices

Source: International Aquafeed, 2000

The critical need to reduce feed costs to match low ex-farm prices of tilapia:

Korea: 45%Malaysia: 65%Indonesia: 82% Thailand: 84%

The escalating cost of imported feed ingredients such as fish meal, soybean meal, wheat flour, fish oil, etc.

!

!!!!

!

Tilapia Feeds

" Protein sources � fish meal, vegetable proteins.

" Carbohydrates � wheat flour, corn flour, etc.

" Lipids � fish oil, vegetable oils.

" Vitamins and minerals.

" Binder and other additives.

Feed formulation depends mainly on fish size

Least-cost formulation for tilapia feeds

Nutrient Limit Prestarter Starter Grower Finisher

Protein Min 40 30 25 20

Lipid Min 4 4 4 4

Lysine Min 2.04 1.53 1.28 1.02

Total P Max 1.5 1.5 1.5 1.5

Fiber Max 4 4 4 8

Fishmeal Min 15 12 10 8

Source: Chawalit et al. 2003 (CP group)

Lipids• source of energy• source of essential fatty acids• absorption of fat-soluble vitamins• cellular & membrane structures• precursors of hormones• imparts flavor to diets• affects diet texture

Lipid levels in tilapia feeds

Hybrid tilapia (O. niloticus x O. aureus)

0

50

100

150

200

250

0 5 10 15 20Dietary lipid level (%)

% W

eigh

t gai

n

Minimum Maximum

12

Corn starch vs. corn oil/ CLO/ lard (1:1:1) Chou & Shiau, 1996

Lipid levels in tilapia feeds

Commercial tilapia diets ≤ 5% lipid

Tilapia zillii (El-Sayed & Garling, 1988).

• Dextrin vs. CLO-SBO mix (2, 5, 10, 15% lipid)

• No significant growth increase from 5 -15% lipid

Hybrid tilapia (O. mossambicus x O.aureus)(Fitzsimmons et al., 1997)

• 3, 6, 8% dietary lipids fed for about 3 months

• No significant difference in growth and FCR

Essential Fatty AcidsContradictory results as to the

requirement of tilapia for n-3 and n-6 PUFA

• require only n-6 PUFA• require both n-3 and n-6 PUFA• > 1% 18:3n-3, DHA or EPA depress growth

0.5 to 1% n-3 and n-6 PUFA until further

research

Status of fish oil use in aquafeeds

# Aquaculture consumes 70% of the total global supply of marine fish oil

# Forecasted to use 97% of fish oil supplies by the year 2010

# Cost of fish oils continue to increase due to:! stagnation in marine capture fisheries! human dietary fish oil supplements! animal livestock industry

01000200030004000500060007000

1985 1990 1995 2000

Year

Met

ric T

ons

(x 1

000)

Aquaculture production on aquafeedsGlobal fish oil production

Aquaculture production versus Fish oil production

1995 1996 1997 1998 1999 2000 2001 2002 2003Year

0

5

10

15

20

25

30

35

Mill

ion

tons

Fish oilRapeseed oilPalm oilSoybean oil

World production of fish oil, rapeseed oil, palm oil and soybean oil

Malaysia 51%

Thailand 2%Nigeria 3%

Colombia 2%Equador 1%

Others 10%

Indonesia 30%

World Palm Oil Producers

Source: Oil World

Palm Kernels

Crude Palm Oil

Palm KernelMeal

Crude Palm

Kernel Oil

Palm Fatty Acid

Distillates

RBD Palm Olein

Bleaching

Deodorization

Distillation

Lipid source 10.0%Casein 32.0%

Gelatin 6.0%

Dextrin 27.8% Vitamin mix 3.0%Mineral mix 5.0%

CMC 1.5%

Cellulose 14.8%

Composition of Semipurified Diets

35% protein and 14.6 kJ/g diet

Dietary Lipid Source Tested:10% Cod liver oil (CLO)10% Sunflower oil (SFO)10% RBD palm olein (RBDPO)10% Crude palm oil (CPO)10% Crude palm kernel oil (CPKO)5% CLO + 5% Palm fatty acid distillate (PFAD)

14:0

16:0

16:118:0

18:1

18:2n618:3n3

18:4n3

20:120:4n6 20:5n3

22:1

22:5n3

22:6n3

Fatty Acid CompositionCod liver oil (CLO)

14:016:0

16:118:0

18:1

18:2n6

16:0

16:118:0

18:1

18:2n6

18:3n3

Sunflower Oil (SFO)

Crude Palm Oil (CPO)

Refined Palm Olein(RBDPO)

8:0

10:0

12:0

14:0

16:016:1 18:118:2n6

14:016:0

18:0

18:1

18:2n6

Crude Palm Kernel Oil (CPKO)

Palm Fatty Acid Distillate (PFAD)

CLOSFO

CPOCPKO

CLO:PFAD

0%

20%

40%

60%

80%

100%

Type of fatty acids:

SaturatesMonoenesn-3 PUFAn-6 PUFA

Fatty acid composition of experimental diets

CLO SFO CPO CPKO CLO:PFAD0

10

20

30

40

50

% pa

lmit i

c a c

id

% Palmitic acidDiet Muscle

Muscle palmitic acid (16:0) content ofhybrid tilapia fed various dietary lipid and

palm oil source

a

c

ab bc

CLO SFO CPO CPKO CLO:PFAD0

10

20

30

40

50

60

70

% li

nole

ic a

cid

% Linoleic acidDiet Muscle

Muscle linoleic (18:2n-6) content of hybrid tilapia fed various dietary lipid and palm oil

source

b

a

b bc

CLO SFO CPO CPKO CLO:PFAD0

5

10

15

20

25

30

% n

-3 P

UFA

% n-3 PUFADiet Muscle

Muscle total n-3 PUFA content of hybrid tilapia fed various dietary lipid and palm

oil source

a

cb

c

b

CLOSFO

CPOCPKO

CLO:PFAD

0%

20%

40%

60%

80%

100%

Type of fatty acids:

SaturatesMonoenesn-3 PUFAn-6 PUFA

Muscle fatty acid composition of red hybrid tilapia fed various

dietary lipids

ConclusionFeeding diets containing palm oil have NO negative effects on:

• growth and feed utilization efficiency

• fillet yield and other body/organ indices

• fillet and body proximate composition

• blood indices such as hematocrits

Positive aspects of palm oil use in tilapia feeds:

$Lower cost and sustainable production of palm oil.

$ High oxidative stability thereby minimizing feed rancidity.

$ Does not significantly increase lipid content in tilapia fillets.

$ Does not markedly increase the saturated fatty acids in tilapia fillets.

$ Limits the deposition of less desirable fatty acids such as linoleic acid (18:2n-6)

! human health concerns.

! fish health concerns.

$ Lower PUFA content in fish fillet minimizes lipid peroxidation of tissue.

$ Possible beneficial effects of natural antioxidants in crude palm oil.

Positive aspects of palm oil use in tilapia feeds:

% The deposition of desirable fatty acids such as EPA and DHA is decreased.

Negative aspect of palm oil use in tilapia feeds:

Fish Consumption, Fish Oil, Omega-3 Fatty Acids and Human Health

• There are 2 series of essential fatty acids that cannot be synthesized by animals or humans and must be supplied in the diet.

• n-6 series derived from linoleic acid (18:2n-6) and n-3 series from linolenic acid (18:3n-3).

• Two derivatives of linolenic acid are physiologically important compounds for human health:

• EPA = eicosapentaenoic acid (20:5n-3)

• DHA = docosahexaenoic acid (22:6n-3)

• EPA and DHA are abundant in fish oils.

• Death rates from ischemic heart disease (% of all deaths) in the United States, Denmark and Greenland are 40.4, 34.7 and 5.3, respectively (Dyerberg, 1982).

• The American Heart Association strongly endorses the use of omega-3 for cardiovascular disease prevention (AHA, 2002).

• Several countries including the World Health Organization have made formal population-based dietary recommendations:

• 0.3-0.5 g/day of EPA + DHA

• 0.8-1.1 g/day of linolenic acid

• two fatty fish meals per week.

Positive effects of fish and fish oils on cardiovascular diseases

Beneficial Effects of EPA and DHA% Cardiovascular diseases

% Inflammatory diseases

% Arthritis

% Multiple sclerosis

% Cancer

% Skin diseases

% Asthma

% Normal brain functions

% Strokes

% Nephritis

% Lupus erythematosis

% Preterm birth

% Diabetes mellitus

% Improves learning ability

% Mood and behavior

% Healthy immune system

Data from various scientific sources

FO

FO:CPO

CPO:LSOCPO

SBO0%

20%

40%

60%

80%

100%

Type of fatty acids:

SaturatesMonoenesn-3 PUFAn-6 PUFA

Tilapia fillet fatty acid composition after feeding diets with various oils for 5 months

FO

FO:CPO

CPO:LSOCPO

SBO0

5

10

15

20

25

% to

tal f

a tty

aci

d s Month5678

Total n-3 fatty acids in tilapia fillet after reverting back to a fish oil-based diet for 3 months

*

* *

**

* **

*

FO

FO:CPO

CPO:LSOCPO

SBO0

5

10

15

20

25

30

35

% to

tal f

atty

aci

d s Month5678

Total n-6 fatty acids in tilapia fillet after reverting back to a fish oil-based diet for 3 months

* *

*

** *

*

* *

*

*

*

Conclusions• The total omega-3 fatty acids in tilapia fillet of fish fed palm oil-based diets may be markedly increased by:

• formulation strategies � blending with fish oil or linseed oil.

• reverting back to a fish oil-based diet just before harvest to manipulate the fatty acid composition.

• Palm oil is a better fish oil substitute compared to soybean oil as less undesirable omega-6 fatty acids are deposited in fish fillets.

0

2

4

6Hardness

Chewiness

JuicinessSweetness

Sourness

FO FO+CPO LSO+CPO CPO SBO

Sensory evaluation of tilapia fillets fed various dietary lipids

Based on 10 trained sensory panelists from SeaPack Food Ltd, a major seafood processing factory in Malaysia.

0

2

4

6

8Aroma

Whiteness

Appearance

Sweetness

SournessBitterness

Hardness

Chewiness

Juiciness

FO FO+CPO LSO+CPO CPO SBO

Sensory evaluation of tilapia fillets fed various dietary lipids and after 6 months frozen storage

Based on 6 trained sensory panelists from Fisheries Research Institute, Malaysia.

*

$Possible beneficial effects of natural antioxidants such as vitamin E in crude palm oil when deposited in tilapia fillets.

An added human health benefit of using palm oil in tilapia feeds:

PFADCPOCPKOSFOCLOVit. E

21%18%7%88%96%α-T

405498343582235Totalmg/kg

17%10%---δ-T342%

-18%

-2%---3%-β-T

2%-8%4%γ-T

46%45%--γ-T3----β-T3

24%48%--α-T3--1%-δ-T

Total tocopherols and tocotrienols in experimental diets

4

30

56

105123

144

112

TAC-0

TAC-25

TAC-50

TAC-100

CPO-EPFAD

CPO

Dietary vitamin E sources

020406080

100120140160

mg

vit a

min

E /

k g d

iet

alpha-Tbeta-Tgamma-Talpha-T3gamma-T3delta-T3

Vitamin E composition in experimental diets

TAC-0

TAC-25

TAC-50

TAC-100

CPO-EPFAD

CPO

Dietary vitamin E sources

0%

20%

40%

60%

80%

100%

alpha-Tbeta-Tgamma-Talpha-T3gamma-T3delta-T3

Tocopherol and tocotrienol concentrations in the muscle of tilapia after 8 weeks

1.8

4.6

7.1

9.7

6.2

8.4

6.7

TAC-0

TAC-25

TAC-50

TAC-100

CPO-EPFAD

CPO

Dietary vitamin E source

0.0

2.0

4.0

6.0

8.0

10.0

12.0

ug v

itam

i n E

/ g

tissu

e

alpha-Tbeta-Talpha-T3gamma-T3delta-T3

0

20

40

60

80

100

nmol

MD

A/g

tiss

ue

TAC-0TAC-25TAC-50TAC-10

0

CPO-E3%

PFAD10

% CPO

Dietary vitamin E source

TBARS in muscle of tilapia fed various dietary vitamin E source

a

b

cc

c c

d

Total PUFA in muscle

Diets 1- 5 = 9.1 to 11.3 %

Diet 6 = 12.6 %

Diet 7 = 17.1 %

Accumulation of vitamin E in fillet of tilapia fed increasing levels of tocotrienol-rich fraction from palm oil for 9 weeks

2.03.3

8.0

11.1

17.8

TRF-0

TRF-30

TRF-60

TRF-120

TRF-240

Dietary vitamin E Level

0.0

5.0

10.0

15.0

20.0

ug v

itam

in E

/ g

tiss u

e

alpha-Tgamma-Talpha-T3gamma-T3delta-T3

TBARS in muscle of tilapia fed increasing levels of a tocotrienol rich fraction from palm oil

0

40

80

120

160

200nm

ol M

DA

/g ti

ssue

TRF-

0

TRF-

30

TRF-

60

TRF-

120

TRF-

240

Dietary Vitamin E Level

a

b

cc

c

Conclusion& Tissue concentrations of tocopherols and tocotrienols increased in response to increasing dietary concentrations.

&Antioxidant potency of various vitamin E sources for hybrid tilapia:

palm vitamin E > α-tocopherol acetate.

& Biodiscrimination mechanism (α-T transfer protein) probably exist in tilapia liver with greater affinity for α-T > α-T3 > γ-T3.

Conclusion&Palm tocopherols and tocotrienolssignificantly improve oxidative stability of tilapia fillets that will translate to longer shelf life and freshness for seafood products.

Conclusion&Deposition of tocotrienols adds value to tilapia products especially if they are eaten raw as sashimi or sushi.

Human health benefits of palm tocotrienols:

• Higher anti-oxidant potency.

• Hypocholesterolaemiceffects.

• Anti-cancer properties.

• Prevention of cardiovascular diseases.

Nutritionally enhanced chicken eggs

It is not inconceivable that one day in the near future, tilapia fillets will also be labeled

just like poultry eggs to advertise

nutritionally enhanced seafood

products at a premium price for

the health-conscious consumer.

An overview of lipid nutrition with emphasis on alternative lipid sources in

tilapia feeds

Wing-Keong Ng & Cheong-Yew Chong

Fish Nutrition LaboratorySchool of Biological Sciences

Universiti Sains MalaysiaPenang, Malaysia