05.05.2014

1

NUTRITION AND PRODUCT QUALITY

Giuseppe Bee

Agroscope Institute for Livestock Sciences (ILS)Email: giuseppe.bee@agroscope.admin.ch

AWAITING CHALLENGES

• By 2050 world population will grow from 7.2 to 10.9 billion (USCB)

• Food production needs to increase by 60 to 70% in the next 35 yrs.

• By 2020 an increase of 20% needs to be already achieved (OECD).

• Food from animal sources plays a key role thus animal protein

production needs to grow at least 3 times by 2050 (FAO).

• Swine, poultry, beef and fish production needs to be multiplied by 1

and 10, respectively.

• Conclusion and key challenge:

• Due to lack on arable land, increase in intensification is inevitable.

• Environmental friendly, sustainable food and animal feed production

with limited availability of resources.

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CHALLENGES FOR THE SWINE PRODUCTION SECTOR

• Swine producers will have “to do more with less”.

• Foreseen scenarios are:

• Higher feed costs (corn, soybean…)

• More pressure from legislation (e.g. antibiotics, animal welfare…)

• Greater expectations from consumers towards product quality

• How to achieve this goal:

• Improve feed efficiency

• Optimal relationship between slaughter weight and feed efficiency

• Improve feeding techniques and feeding programs based on pig nutrient

requirements = precision feeding

• Improve animal health

• Decrease animal losses from birth to slaughter

HOW CAN PORK QUALITY BE DEFINED?

Nutritionalquality

Eatingquality

Hygienicquality

Processingquality

• Protein

• Fat

• Mineral & vitamins

• Energy

• pH

• Water-holding capacity

• Lipid composition

• Connective tissue content

• Anti-oxidative status

• Content of microorganisms

• Residues

• Contaminants

• Appearance

• Color

• Marbling

• Odor

• Flavor

• Juiciness

• Tenderness

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RELEVANCE OF THE QUALITY CRITERIA

Price relevant

• Slaughter weight

• Lean meat content

• Fat quality (e.g. CH)

• Off-odor (production of entire males)

Not price- but quality- and

image-relevant

• Marbling• Inter- and intramuscular fat content

(IMF)

• pH45 min, pH3 h, pH24 h

• Water holding capacity (WHC)• Drip loss

• Thaw loss

• Cooking loss

IMPORTANCE OF DEPOSITED FAT

Carcass leanness determined by

Fat compartments relative importance allometric growth rate

• Subcutaneous fat 60 – 70% +++

• Perirenal fat 5% ++++

• Intermuscular fat 20 – 35% ++

• intramuscular fat < 1% +

Marbling is a major trait affecting

• Nutritional quality

• Eating quality

• Processing quality

early developing

late developing

Increased IMF equals:

• enhanced acceptability

• improved perception of

texture and taste

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NUTRITION AND FAT DEPOSITION RATE

IMF

Feed

restriction

Compensatory

growth

Protein level

Protein : energy

ratio

Lysine level

↓↓↓

↑↑↑

↑↑↑

Lebret et al., 2001

Anim. Sci. 72:87-94

Gondret and Lebret, 2001

J. Anim. Sci. 80:3184-3194

13.1% CP18.3% CP

↑↑↑Lebret et al., 2001

Anim. Sci. 72:87-94IMF, %

IMF, %

IMF, %

Backfat ↑↑ ←

Backfat ↑↑ ←

→ Backfat ↓↓↓ → Backfat ↑

IMF CONTENT AND EATING QUALITY

Influence of intramuscular fat content on willingness to eat

(A) and to purchase (B) pork Fernandez et al., 1999Meat Sci. 53:67-92

Before tasting

Before tasting

After tasting

After tasting

Increased IMF levels on

consumer acceptability

• Is favorable up to 2.5 –

3.5% IMF

• Favorable effect of IMF

is only valid if it is not

associated with an

excessive increase in

intermuscular fat

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OPPORTUNITIES AND POTENTIAL OF THESE STRATEGIES

• Genetic baseline for IMF deposition

• e.g.: Duroc > Landrace > Large White > Pietrain

• Market demand

• Choose feeding strategies accordingly

• Progressive EAAS:energy ratio reduction + limiting dietary energy

• Increase in IMF > adipose tissue

Relationship is questioned

Rincker et al., 2008J. Anim. Sci. 86:730-737

Tenderness

Pork flavor

Juiciness

Shear force

Marbling does not influence eating experience and tenderness.

Additionally, consumers appear to select less marbled pork in the retail case because they

prefer to purchase leaner pork.

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WATER-HOLDING CAPACITY (WHC) AND TENDERNESS

pH decline post-mortem• Muscle glycogen stores

• Glycolysis rate

Proteolysis (muscle to meat conversion)

• Calpain activity

• Muscle calcium level

WHAT ARE MAJOR INFLUENCING FACTORS?

• Pre-slaughter handling of the pigs

• Fasting time, transport time, lairage time, animal handling to the

stunning area

• Post-slaughter handling of the carcass

• Carcass chilling regime (e.g. duration of blast-chilling), hot or cold-

deboning

• Nutritional strategies which affect:

• Muscle protein turnover

• Calcium metabolism

• Glycogen metabolism

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MUSCLE PROTEIN TURNOVER: WHC AND TENDERNESS

• Compensatory growth

• Elevates muscle protein turnover

• Challenge is to establish optimal length of compensatory period → level of protein

degradation

• Dietary vitamin D3 → elevates tissue calcium level

• Effects on calpain activation = important for early post-mortem proteolysis

• Duration prior to slaughter and level

Protein

synthesis

Protein

degradation

Feeding strategy → Proteolytic potential → + / - proteolysis

• WHC

• tenderness

in vivo

muscle growth

After slaughter

(post-mortem)

Adapted from Kristensen et al., 2002J. Anim. Sci. 80:2862–2871

MUSCEL GLYCOGEN METABOLISM: WHC, COLOR…

Ways to reduce muscle glycogen stores

• Short time feeding of a high fat (18%)/protein (24%) and low

carbohydrate (<5%) diet

• Reduced muscle glycogen stores

• Higher pH 45 min, enhanced WHC

• Delayed conversion of glycogen to lactate

Muscle gylcogen Lactate

Anaerobic process

pH-decline• WHC

• Drip loss

• Juiciness

• Meat color• Lightness

Feed-induced drop of muscle glycogen level in the muscleRosenvold et al., 2001Meat Sci. 57:397-406

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MUSCEL GLYCOGEN METABOLISM: WHC, COLOR…

Delayed glycolysis resulting in longer sustained calpain induced

proteolysis:

• Improve WHC

• Drip loss

• Color

Muscle gylcogen Lactate

Anaerobic process

slowed

Creatine(e.g.: Creatine monohydrate)

Phosphocreatine(muscle energy reserve)

Different effects of dietary creatine monohydrate fed to Duroc

and Landrace pigs on WHC (Young et al. 2004)

ADIPOSE TISSUE QUALITY IS IMPORTANT

Adipose tissue

Fat content & composition

Texture of fat

Oxidative stability

These traits are dependent on the fatty acid composition of the adipose

tissue

• Saturated fatty acid (SFA: 16:0, 18:0)

• Monounsaturated fatty acid (MUFA: 16:1, 18:1)

• Polyunsaturated fatty acid (PUFA: 18:2, 20:4, 18:3, 20:5)

Firm texture and high

oxidative stability is a

prerequisite for the production

of high quality meat products

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Fat composition – de novo synthesis or diet

18:2n-6

18:3n-6

20:3n-6

20:4n-6

18:3n-3

18:4n-3

20:4n-3

20:5n-3 (EPA)

22:6n-3 (DHA)

22:5n-3 (DPA)

24:6n-3

D6-desaturation

elongation

D5-desaturation elongation

Elongation & D6-desaturation

Linoleic acid Linolenic acid

b-oxidation

Glucose

Stearic acid

Palmitic acid

Oleic acid

Feed

Differences in the composition between tissues

Inner layer

Outer layer

These differences are independent of

• Nutrition

• Breed

• Sex

• Management

Unsaturation degree (=ratio of PUFA + MUFA : SFA) of fat deposits

follows a negative gradient from outside to inside

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NUTRITIONAL FACTORS ASSOCIATED WITH FAT QUALITY

Unsaturation

degree

Feed

restriction

↑↑↑ → Fat deposition rate ↓↓↓

SFA MUFA PUFA

Rel

ativ

e to

to

tal f

atty

aci

ds,

%

0

10

20

30

40

50

HS (TZ: 842 g/d)

LS (TZ: 461 g/d)

H: 14.0 MJ VES/kg

L: 8.8 MJ VES/kg

(Bee et al., 2002)

Dietary fat

composition

= ↑ PUFA levelPUFA level in the diet, g/MJ VES

0.7 1.0 1.2 1.6

PUFA

leve

l, %

of t

otal

fatt

y ac

ids

6

8

10

12

14

16

18

20

22

Backfat - outer layer

Backfat - inner layer

Leaf fat

(Perdrix und Stoll., 1995)

↑↑↑

Dietary

conjugated

linoleic acid (CLA)

↓↓↓ → Fat deposition rate ↓

Intrinsic factors (gender, breed, age) affecting

the extent of deposited fat tissue are the baseline

for the impact of the mentioned extrinsic factors

Oxidative

stability

Antioxidants

• Vitamin E

• Selenium

• Vitamin C

↑↑↑

WHICH QUALITY IS REQUESTED?

Contradiction between requirements

• Meat processors

• Firm fat = high proportion of SFA and limited proportion of PUFA +

MUFA

• Not prone to oxidative alterations

• Less problematic due to the availability of antioxidants

• Human nutrition

• Limit SFA and increase PUFA intake

• Lower n-6 to n-3 fatty acid ratio of dietary fat

• Greater proportion of long chain n-3 fatty acids

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POSSIBLE STRATEGIES FOR “TO DO MORE WITH LESS”

• Improve production efficiency

• Selection for decreased residual feed intake (RFI*)

• Selection for “less demanding” pigs

e.g. able to cope with lower dietary protein supply

able to cope with greater dietary crude fiber feed

• Use of alternative feed sources

• High crude fiber feedstuff + enzyme supplements

• Insect proteins

• Lecithin

• Precision feeding

• Improve growth models including impact on muscle development

*RFI = difference between observed and expected feed intake based on maintenance and requirement. Low RFI = more efficient pigs

AWAITING CHALLENGES: SELECTION FOR LOW RFI

Low RFI

Carcass fat IMF

MuscleMuscle fiber

hypertrophyGlycogen

pHultimate

WHC

↓↓

↑↑

↓↓

↑↑ ↑↑

↓↓

↓↓

Tenderness↓↓

Possible strategies to counteract the negative effects of RFI selection

• Gradually reduce lysine supply (precision feeding)

• Elevate IMF without affecting overall carcass fat deposition

• Use compensatory growth strategy

• Elevate proteolytic potential of the muscle the day of

slaughter

• Use glycogen reducing diets prior to slaughter

• Reduce glycogen stores and delay pH decline and improve

WHC

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AWAITING CHALLENGES: SELECTION FOR HYPERPROLIFICACY

Increasing

litter size

Low birth

weight pigs

Muscle fiber

hyperplasia↑↑ ↓↓

Growth

efficiency↓↓

Tenderness WHC Carcass fat

↑↑↓↓↓↓

Possible strategies to counteract the negative effects of low birth weight pigs

• Adapt feeding to impaired growth potential of these pigs

• Restricted feeding

• Improve early life feeding (lactation period)

• Artificial feeding aiming to increase muscle fiber hyperplasia

CONCLUDING REMARKS

• A variety of nutritional tools/strategies are known to affect growth

efficiency and meat quality

• Interactions among these nutritional tools/strategies (and intrinsic

factors) are not well understood and awaits evaluation

• New technologies (NGS, -omics) will help understand underlying

mechanisms of interactions

• Only if pre-slaughter management of pigs and post-slaughter

handling of carcasses is optimal, nutrition strategies is decisive

for pork quality.