Kevin J Shingfield's presentation from the Sustainable Food Trust's meeting: What role for grazing livestock in a world of climate change and diet-related disease?

1. Benefits of forage systems on product
quality: mechanisms and implications
Kevin J. Shingfield
kes14@aber.ac.uk

2. Ruminant foods: Food choices, health and
environmental impact
• Desirable products
• High biological value protein
• Source of bioactive lipids
• Rich in micronutrients
• Rich in saturates
• Contain trans fatty acids
• Environmental footprint

3. Impact of grazing on nutritional value
• Increase carotenoids/tocopherols
• Enrich PUFA (18:3 n-3)
• Elevate cis-9, trans-11 CLA
• Lower 12:0, 14:0 and 16:0
• Increase carotenoids/tocopherols
• Lower n-6/n-3 PUFA ratio
• Increase 18:3/20:5/22:6 n-3
• Elevate cis-9, trans-11 CLA

4. Incidence of chronic human diseases
• Coronary heart and cerebrovascular disease is the leading
cause of death worldwide
• 80% of the burden now occurring in developing countries
Direct and indirect costs of CVD per annum
• EU25 € 200bn (Allender et al., 2008)
• US $ 403bn (Thom et al., 2006)
• India $ 237bn (International Heart Summit, 2011)

5. trans fatty acids and health
• trans fatty acids increase in coronary heart disease risk
(Willett et al., 1993; Kromhout et al., 1995; Ascherio et al.,
1999)
• trans fatty acids increase LDL but lower HDL cholesterol and
elevate total:HDL cholesterol ratios (Mozaffarian et al.,
2006)
• trans fatty acids elevate plasma TAG (Mensink et al., 2003),
Lp(a) lipoprotein (Ascheiro et al., 1999) and decrease mean
LDL particle size (Mauger et al., 2003)
• Possible role of trans fatty acids in inflammation which is a
risk factor for atherosclerosis and sudden cardiac arrest
(Mozaffarian et al., 2006)

6. • CLA inhibits chemically induced mouse epidermal tumours
(Ha et al., 1987)
• CLA inhibits chemically induced forestomach neoplasia in
mice (Ha et al., 1990)
• CLA protects against abberant crypt foci formation in the rat
colon (Liew et al., 1995)
• CLA shown to be a potent anticarcinogen in the mammary
model of cancer in rats (Ip et al., 1991; 1994; 1999)
cis-9, trans-11 CLA and health

7. Long chain n-3 fatty acids and health
• Lower cardiovascular disease risk
• Anti-arrhythmic effects on heart muscle
• Improve arterial plaque stability
• Anti-thrombotic properties
• Lower endothelial activation
• Role in infant brain and retina function
• Positive effect on immune function
Ruxton et al., 2005

8. Effect of grazing: Mechanisms

9. Mouth
Abomasum
Dietary Lipid
18:2n-6 and 18:3n-3
CLA and CLNA
trans 18:1
18:0
Lipolysis
Biohydrogenation
Ruminal lipolysis and biohydrogenation
18:3 n-3 92%
18:2 n-6 86%

10. Ingested plant cellsFrom
mouth Abomasum
Organelle phospho- &
galacto lipid
Free fatty acids
Organelle phospho- &
galacto lipid
Intact cell Ruptured cell
Rumen microflora
Bacterial
lipolysis
Free Pool C18 PUFA
Conjugated dienes and trienes
Trans monoenes
18:0
Protozoa
Green odour
compounds
Plant
lipolysis
Rumen
Fresh forage: Possible mode of action
Lee et al., 2007;
Huws et al., 2011, 2012
Esterified lipid
Trans FFA
PUFA

11. Ruminal protozoa are rich in polyunsaturated fatty
acids due to ingestion of chloroplasts
Scale bars – 20 µm
Epidinium sp. isolated from the rumen of steers fed fresh grass
Huws et al. (2009). FEMS Microbiology Ecology, 69: 461-471. Huws et al., 2009

12. Distribution of trans 18:1 isomers
0.28 0.24 1.03 3.02 3.8
49.4
10.2
17.6
6.9 7.5
0
10
20
30
40
50
60
4 5 6-8 9 10 11 12 13/14 15 16
(%)
Double bond position
Pasture (Beef muscle)
0.2 0.2
14.7
17.3
21.7
20.3
14 13.6
3 2.3
0
5
10
15
20
25
4 5 6-8 9 10 11 12 13/14 15 16
(%)
Hydrogenated oil
Stender and Dyerberg, 2003; Dannenberger et al., 2004

13. Shingfield and Wallace, 2014
Synthesis of CLA in ruminants

14. Effect of grazing: Implications

15. Breeding for improved product quality
Breeding: combining novel
characteristics with an existing
set of required traits

16. Enhancing the positive characteristics of grazing on
the nutritive value of ruminant foods
• Grass breeding
Selection for the proportions of 18:3n-3 and/or tocopherols
Production of higher lipid varieties
• Rumen microbiology
Development of targeted anti-microbial agents
Testing of aldehydes and volatile components
• Animal breeding
Optimising animal genetics for grazing
Selection of animals with higher desaturase activity and/or lower
activity of enzymes involved in de novo fatty acid synthesis
Developing proxy traits for ruminal lipolysis and/or biohydrogenation

17. Thank you for your attention