TILAPIAS FROM DIFFERENT TILAPIAS FROM DIFFERENT AQUACULTURE SYSTEMS CONTAIN AQUACULTURE SYSTEMS CONTAIN VARIABLE AMOUNTS OF VARIABLE AMOUNTS OF -3 -3 AND AND -6 -6 POLYUNSATURATED FATTY ACIDS: POLYUNSATURATED FATTY ACIDS: IMPLICATIONS FOR HUMAN NUTRITION IMPLICATIONS FOR HUMAN NUTRITION Ioannis T. Karapanagiotidis 1 *, Michael V. Bell 1 , David C. Little 1,2 , Amararatne Yakupitiyage 2 1 Institute of Aquaculture, University of Stirling, UK 2 AARM, SERD, Asian Institute of Technology (AIT), Thailand
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TILAPIAS FROM DIFFERENT AQUACULTURE SYSTEMS CONTAIN VARIABLE AMOUNTS OF -3 AND -6 POLYUNSATURATED FATTY ACIDS: IMPLICATIONS FOR HUMAN NUTRITION Ioannis.
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TILAPIAS FROM DIFFERENT TILAPIAS FROM DIFFERENT AQUACULTURE SYSTEMS CONTAIN AQUACULTURE SYSTEMS CONTAIN VARIABLE AMOUNTS OF VARIABLE AMOUNTS OF -3-3 AND AND -6-6 POLYUNSATURATED FATTY ACIDS:POLYUNSATURATED FATTY ACIDS:IMPLICATIONS FOR HUMAN NUTRITIONIMPLICATIONS FOR HUMAN NUTRITION
Ioannis T. Karapanagiotidis1*, Michael V. Bell1,
David C. Little1,2, Amararatne Yakupitiyage2
1Institute of Aquaculture, University of Stirling, UK2AARM, SERD, Asian Institute of Technology (AIT),
ThailandSupport from the Aquaculture and Fish Genetics Programme, DFID,
UK
BasicBasic ConceptsConcepts
Fatty acids are the basic units of fats and oils (lipids)
The polyunsaturated fatty acids (PUFA) are a group of fatty acids with great significance in animal nutrition (including fish and humans)
PUFA are categorised according to their chemical structures, from which the most important are those of the -3 and -6 fatty acids.
The Importance of PUFAThe Importance of PUFA
-3 and -6 PUFA are essential (Essential Fatty Acids or EFA) for normal growth, development and reproduction of all vertebrate organisms, including fish & humans
Because of the fact that animals cannot synthesise -3 and -6 PUFA inside their body (de novo), these should be provided from the diet
The Vital Importance of The Vital Importance of -3 PUFA-3 PUFA
Particularly the -3 PUFA (i.e.DHA & EPA) have beneficial effects on general health and prevent many health disorders such as:
• Diseases of the heart & of blood vessels• Diseases of the immune system• Cancer & respiratory diseases• Allergic reactions
The Human Diet – The Human Diet – A growing A growing concernconcern In recent decades, it is fact that the
profiles of fats in Western diets have become increasingly unbalanced
The intake of saturated fat and -6 PUFA has increased, whereas -3 PUFA intake has decreased
Formerly the ratio -3/-6 was 1:5 but it has now declined to ratios below 1:20
Changes in Fat and Fatty Acid Intake in Western Diets(source: International Fishmeal & oil Manufacturers Association)
0
5
10
15
20
25
30
35
40
45
calories from fat (%)
0
0.4
0.8
1.2
1.6
2 ratio
Total Fat
Saturated Fat
The Human Diet – The Human Diet – A growing concernA growing concern
These changes in the fat patterns have been linked with many common health disorders in the western world (i.e. Coronary Heart Disease, cancer etc.)
However, these changes appear to be spreading and influencing diets around the World
The incidence of many health disorders is now increasing in several countries in Asia
The Availability of Fats by economic group (1961-1990, 165 countries) Source: FAO Food balance sheets, Agrostat PC, 1993
Fish is not only a high-quality protein food, for which there are many competing alternatives in nature
But also contains high concentrations of -3 PUFA
(i.e. DHA & EPA) for which there are currently no real competing alternatives
Fish is by far the richest source of -3 in nature
Fish in the Human Diet: Fish in the Human Diet: A Unique Nutritional RoleA Unique Nutritional Role
Linkages between lipids and rural Linkages between lipids and rural aquacultureaquaculture The inland Asian communities are
traditionally dependent on freshwater aquatic foods, and especially fish
There is an increasing reliance on farmed fish as diets and livelihoods change
Is this more better? What are the qualitative impacts of increasing fish consumption through intensification of aquaculture?
Impacts of intensificationImpacts of intensification
Most aquaculture production in Asia is semi-intensive relying on use of both fertilisation and supplementary feeding
The traditional supplementary feeds are high energy brans and oilcakes, which are high in -6 PUFA
The increasing trend towards intensive systems is making use of formulated feeds to satisfy the nutrient requirements of fish
The fish feeds are using an increasing proportion of global marine fishmeal (rich in -3 PUFA), but the least cost formulations, commonly practised, result in more -6 PUFA.
The current studyThe current study
to determine the fat content and fatty acid composition of tilapia (Oreochromis niloticus) produced in systems across a range of intensification
Culture SystemsCulture Systems
Wild fish (reservoir) Nile tilapia natural food
Extensive Polyculture in snakeskin gourami
pondNile tilapia
natural food & minimum
inputs
Integrated with chicken Nile tilapianatural food &
spilled feed
Semi-Intensive culture Nile tilapiafertilised &
supplementary
Intensive pond culture Nile tilapiaonly pelleted
feed
Intensive cage culture in river
Red tilapiaonly pelleted
feed
Culture System Species Feed Inputs
Total Lipid (%) of wet weight muscle tissue
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
wild polyculture integrated semi-intensive intensive nile red Tilapia
TL
The Amounts of FA in edible muscle tissue (mg/g)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
wild polyculture integrated semi-intensive intensive red tilapia
mg/g
Saturated
MUFA
PUFA
ratios (in edible muscle tissue)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
wild polyculture integrated semi-intensive
intensive red tilapia
mg FA/g tissue
0.0
0.5
1.0
1.5 w-3/w-6
Individual Fatty Acids (% of Total FA content)
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
wild polyculture Integrated Semi-intensive
Intensive Red tilapia
EPA
DHA
18:2 n-6
Conclusions of the studyConclusions of the study
The fat content of tilapia is moderate but increases as we shift from extensive production totally dependent on natural food to more intensive culture systems.
Tilapia contain considerable amounts of the valuable DHA in the edible muscle tissue
Conclusions of the studyConclusions of the study
-3/-6 ratios in tilapia cultured at different intensities ranged from 1:1 to 1:2, indicating their high lipid nutritional value
However, higher levels of -6 and lower ratios of -3/-6 were found in the more intensively farmed fish compared to the wild fish and those cultured mainly on natural food.
General ConclusionsGeneral Conclusions
The aquaculture sector has a very important role to play both in the developing and developed world by providing food security and ensuring future fish supplies. Fish is the richest source of the -3 PUFA in nature and consumption of fish improves human nutrition and health.
However, since the input of -6 PUFA from other dietary components is often excessive in humans it is desirable, or even essential, that fish continue to supply long-chain -3 PUFA in the human diet.