Manipulating the fatty acid
composition including CLA content
of animal products
Professor, Dr. Peter Buttery
Division of Biochemistry & Nutrition
Biosciences School
The University of Nottingham UK
Why Manipulate the fatty acid
composition of animal products?
• To reduce the intake of “bad” fatty acids by
the consumer
• To increase the intake of “good” fatty acids
by the consumer
• To increase sales of such products by
improving their “image”
Dietary Reference Values for Fatty Acids
Population averages (% total energy)
1991
Saturated Fatty Acids
Cis polyunsaturated fatty acids
Cis monounsaturated fatty acids
Trans fatty acids
Total Fatty Acids
10%
6%
12%
2%
30%
Further Recommendations
1994
Population average consumption
of long chain n-3 polyunsaturated
fatty acids should double (from
0.1g/day to 0.2g/day
(not going to discus this here but is
important)
Saturated fatty acid (SFA) intake in
Great Britain
percent energy from SFA
18
16
14
12
10
target
8
6
4
2
0
1992
1993
1994
1995
1996
1997
1998
1999
2000
Source: National Food Survey 2000
Contribution of Animal Products to Saturated
Fatty Acid (SFA) Intake in Great Britain
National Food Survey 2000
other meat
poultry
pork
lamb
beef
eggs
butter
cheese
milk & cream
Meat
22%
Other
39%
SFA per day (g)
Dairy
39%
6
5
4
3
2
1
0
• Meat contributes about 22% of total and
saturated fat intake in the human diet
• Lamb has a high stearate content which
gives a waxy texture, producing poor
organoleptic properties
• Red meat, as part of a balanced diet, is an
important source of protein and iron
Possible
Approaches
• Change fatty acid profile of diet
~ low fat diet
~ biohydrogenation of unsaturated fat
• Protected fatty acids
• Manipulation of de novo fat synthesis that
is reduce the fat content of the carcass
Reduction of fat
•
•
•
•
•
Breeding
Diet
Growth Hormone *
Beta agonists*
CLA?
• *Not legal in Europe but are in many parts of
the world----China?
Fatty acid composition of intramuscular
fat in pigs fed different oils
Fatty acid (g/100g total)
50
45
40
35
30
25
20
15
10
5
0
LF
HF (SO)
HF (RO)
C14:0
C16:0
C18:0
C18:1
C18:2
C18:3
Entire male Landrace*Large White Pigs (3 per group) were grown from 55kg to 120kg
LF diet: no added fat
SO diet: 43.5g/kg sunflower oil + 31.5g/kg rape seed oil
RO diet: 75g/kg rape seed oil
Budd, Salter, Buttery & Wiseman, unpublished data
THE RUMINANT
• Fats over 10% cause problems with rumen
function
• Unsaturated fats are hydrogenated in the
rumen so difficult to alter the diet.
Adipose Tissue Fatty Acid Deposition
in Ruminant Adipose Tissue
DIET
DE NOVO SYNTHESIS
C18:1/C18:2/C18:3
C16:0
C18:0
C18:0
Rumen
C18:1
Adipose Tissue
Fatty acid composition abomasal fluid and
adipose tissue of sheep fed on grass nuts
70
fatty acid (g/100g FAME)
diet
abomasum
subcutaneous
60
50
40
30
20
10
0
14:0
16:0
16:1
18:0
c18:1
t18:1
18:2
18:3
Sources of Ruminant Milk Saturated
Fatty Acids
Mammary Gland
Acetate/
-OH Butyrate
C16:0
C4:0-C14:0
C18:0
C18:1
Diet
Adipose Tissue
Comparison of the fatty acid composition
of duodenal fluid and milk from cows
60
Fatty acid (g/100g total)
50
duodenum
milk
40
30
20
10
18:3
18:2
c18:1
t18:1
18:0
16:1
16:0
14:1
14:0
12:0
<12
0
Fatty acid synthesis in adipose tissue
& mammary gland
MAMMARY
ADIPOSE
Acetyl CoA
Acetyl CoA
Malonyl CA
Acetyl CoA Carboxylase
(ACC)
Malonyl CA
Fatty Acid Synthase
(FAS)
C16:0
C16:0
Elongase
C18:0
C18:0
C18:1
Stearoyl CoA Desaturase
(SCD)
C18:1
Correlation between SCD mRNA and oleate content of
omental adipose tissue of growing sheep
Effect of insulin on SCD gene expression &
oleate synthesis in ovine adipose tissue explants
Ins: 20nM Insulin
Dex: 10nM Dexamethosone
4000
MUFA
2.5
acetate incorp (nMoles)
SCD mRNA (arb units)
3
2
1.5
1
0.5
0
SFA
3000
2000
1000
0
cont
ins
dex
ins + dex
cont
ins
dex
ins + dex
Effect of feeding forage or concentrate-based diets on acetyl CoA
carboxylase(ACC) & stearoyl CoA desaturase(SCD) mRNA
concentrations of subcutaneous adipose tissue in sheep
P<0.001
mRNA (arb. Units/g tissue)
80
forage
conc (150)
conc (350)
70
60
50
40
30
20
10
0
ACC
SCD
Effect of feeding forage or concentrate-based
diets on fatty acid composition of subucateous
adipose tissue in sheep
35
30
fatty acid (g/100g)
grass
conc (150)
conc (350)
25
20
15
10
5
0
14:0
16:0
16:1
18:0
c18:1
t18:1
18:2
18:3
PROTECT FAT FROM RUMEN
• Coat the fat so that it escapes the action of
the rumen bacteria
• The coat is then broken down in either
abomasum or the duodenum
Effect of feeding rumen- protected fish oil on
the muscle fatty acid content of lot-fed cattle
Ashes et al (2000) Recent Advances in Animal Nutrition, 129-140
40
fatty acid (g/100g)
35
30
25
control
Max-EPA
20
15
10
5
0
14:0 16:0 18:0 c18:1 t18:1 18:2 18:3 20:5 22:6
(n-6) (n-3) (n-3) (n-3)
Trans-10, cis 12-CLA
Cis- 9, trans 11-CLA
Linoleic acid
Why interested in CLAs?
Suggested health benefits to humans
• Altered nutrient partitioning and
lipid metabolism
• Antiatherogenic
• Anticarcinogenic
• Antidiabetic (type II diabetes)
• Immunity enhancement
• Improved bone mineralization
Production of CLAs in the rumen
Linoleic Acid
cis-9, cis-12 18:2
cis-9, trans-11 CLA
trans-11 18:1
trans-10, cis-12 CLA
trans-10 18:1
Stearic acid
Production of CLA
Rumen
Adipose tissue
Linoleic acid
Linoleic acid
c9, t11
c9, t11
SCD
t11 C18:1
t11 C18:1
Stearic acid
Stearic acid
Effect of feeding forage or concentrate-based diets on the
CLA content of abomassal fluid, subcutaneous adipose tissue
& L. dorsi muscle of sheep
cis 9, trans 11
trans 10, cis 12
1.4
1.4
abomassal
abomassal
1.2
1.2
subcut
subcut
muscle
muscle
1
FAME (g/100g)
FAME (g/100g)
1
0.8
0.6
0.8
0.6
0.4
0.4
0.2
0.2
0
0
forage
conc (150)
conc (350)
forage
conc (150)
conc (350)
Seasonal variation in cis 9, trans 11-CLA
content of milk
1.8
1.6
fame (g/100g)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
feb mar april may june july aug sept
oct
nov
dec
SCD ACTIVITY
• There is some evidence that there is genetic
variation
• Some cows seems to produce more CLA in
the diet than others.Polymorphisms in the
SCD gene?
• We have not been able to find much
variation in adipose tissue and liver of sheep
Production of CLA-enriched butter
Ip et al (1999) J Nutr 129: 2135-2142
Cows fed 5.3% sunflower oil and selected for CLA production
30
control
enriched
g/100g total FA
25
20
15
10
5
0
<12:0 12:0
14:0
16:0
18:0 c18:1 t18:1
18:2
CLA
Effect of CLA on development of
Mammary Cancer in rats
Treatment
Group
Dietary CLA
Tumour
g/100g
incidence (%)*
Control
0.1
93
CLA-enriched
Butter+
0.8
43
*30 rats per group were treated with a chemical carcinogen.
Values represent the number of animals with tumours
adapted from Ip et al (1999) J. Nutr 129:2135-2142
+ primarily cis-9, trans-10 isomer
Could it be used in humans?
• Rats were fed 20% (w/w) butter
• Rats weighed 180g and would probably consume about
10g of food a day (2g) butter
• This is equivalent to 11g butter/kg body weight/day
• Thus a 70kg man would have to consume 770g
butter/day to get the same amount
• More research is needed
• Professor Bauman in the USA working in the area
Manipulating supply of CLA to sheep tissues
• Rumen saturates fatty acids therefore need to protect
CLA supplement (containing equal levels c-9,t-11 and
t-10,c-12) from ruminal degradation to  absorption
in small intestine
Protected
Not protected
CLA
C18:0
CLA
CLA
Rumen protected CLA
Proportion of ingested CLA
reaching Duodenum
% reaching duodenum
70
60
50
c9,t11
t10,c12
40
CLA-80 protected by
Trouw Nutrition: Used
matrix of saturated fat of
vegetable origin and final
product produced by prilling,
spray drying and spray
chilling.
30
Determined to be ~ 70 %
protected in cannulated sheep
by dual-phase markers
20
10
0
CLA-80
pCLA-80
How much do we feed?
• Ostrowska et al., (1999)
• Growing pigs fed CLA-55 (mixture of both isomers)
0, 1.25, 2.5, 5, 7.5, 10g CLA/kg diet
• Fat deposition decreased with increasing CLA
• Fat:lean decreased with increasing CLA
• Av 80 kg pig @ highest dose = 0.19 g CLA/kg body
weight/day
How much do we feed?
•
PCLA ~ 66 % effective at bypassing rumen
biohydrogenation
•
High levels lipid adversely affect rumen function
•
Max amount PCLA supplied daily to small intestine
of av. 40 kg lamb calculated = 0.28 kg CLA/kg BW
•
Predicted that lambs would consume 1 kg DM/day
therefore highest PCLA inclusion was 100 g/kg DM
•
25 and 50g/kg DM groups for dose response
Trial Outline
• 36 ewe lambs
1.
2.
3.
4.
5.
6.
7.
Control (n=6)
Low PCLA (n=5)
Med PCLA (n=5)
Hi PCLA (n=5)
Low Megalac (n=5)
Med Megalac (n=5)
Hi Megalac (n=5)
Inclusion g/kg feed
25
50
100
21.7
43.3
86.6
GE/day (MJ)
18.42
19.42
19.86
21.30
19.14
19.86
21.30
• Megalac controls for lipid coating of PCLA
• Fed for 10 wks, control group designed to grow at 180 g/d
Sample analysis
• Fatty acid composition
– Did the CLA get into the animals tissues?
• Carcass characteristics
– Repartitioning effects of CLA?
Subcutaneous CLA content
trans-10, cis-12
2.5
2.5
2
2
moles/100 moles
moles/100 moles
cis-9, trans-11
1.5
1
0.5
1
0.5
0
pCLA
Meg
1.5
0
Control
25
50
Amount of supplement
100
pCLA
Meg
Control
25
50
Amount of supplement
100
Omental CLA content
trans-10, cis-12
2.5
2.5
2
2
moles/100 moles
moles/100 moles
cis-9, trans-11
1.5
1
1.5
1
0.5
0.5
0
0
pCLA
Meg
Control
25
50
Amount of supplement
100
pCLA
Meg
Control
25
50
Amount of supplement
100
Perirenal CLA content
trans-10, cis-12
2.5
2.5
2
2
moles/100 moles
moles/100 moles
cis-9, trans-11
1.5
1
1.5
1
0.5
0.5
0
0
pCLA
Meg
Control
25
50
Amount of supplement
100
pCLA
Meg
Control
25
50
Amount of supplement
100
L. dorsi CLA content
trans-10, cis-12
2.5
2.5
2
2
moles/100 moles
moles/100 moles
cis-9, trans-11
1.5
1
1.5
1
0.5
0.5
0
0
pCLA
Meg
Control
25
50
Amount of supplement
100
pCLA
Meg
Control
25
50
Amount of supplement
100
Liver CLA content
trans-10, cis-12
2.5
2.5
2
2
moles/100 moles
moles/100 moles
cis-9, trans-11
1.5
1
1.5
1
0.5
0.5
0
0
pCLA
Meg
Control
25
50
Amount of supplement
100
pCLA
Meg
Control
25
50
Amount of supplement
100
Effect of dietary CLA on carcass fat
300
Fat (g/kg)
250
200
150
pCLA
Meg
100
Control
25
50
Amount supplement
100
Carcass characteristics
• No change in carcass composition
 Carcass cold weight
 Back fat thickness
 Omental and perirenal depot whole weights
 Muscle weight (L. Dorsi, V. Lateralis, S.
Tendenosus)
 Eye muscle depth or width
 Liver weight
BUT definite incorporation of CLA into tissues
Accumulation of CLA(t10,c12) in
subcutaneous adipose tissue
CLA(t10,c12)g/100g FA
0.8
pig
sheep
0.6
0.4
0.2
0
0
0.2
0.4
0.8
1.2
1.4
1.6
Dietary CLA(t10,c12) (g/kg diet)
Pig data: adapted from Ostrowska et al (2003)
2.8
5.6
Effect of dietary CLA on carcass fat
PIGS
SHEEP
350
300
300
pCLA
Meg
250
Fat (g/kg)
Fat (g/kg)
250
200
200
150
150
100
0
0.2
0.4
0.8
1.2
1.6
dietary CLA(t10,c12) (g/kg)
100
0
1.4
2.8
5.6
dietary CLA(t10,c12) (g/kg)*
Adapted from Ostrowska et al (2003)
*Corrected for protection
Conclusion
• Tissue CLA content increased but no effect on
carcass
• Maybe ruminant adipose tissue responds
differently to monogastrics?
Conclusions
• Animal products continue to supply a major
proportion of dietary saturated fatty acids
• SCD plays a major role in determining the nature
of fatty acids synthesized in tissues
• It is possible to increase the concentration of
“healthy” fatty acids (e.g. n-3 PUFA & CLA) in
meat & dairy produce but whether the changes can
be great enough to have a significant impact on
human health remains to be established
Acknowledgement
•
•
•
•
Professor Andrew Salter
Dr Sean Richards
Dr Zoe Daniel
Dr Richard Wynn