Impact of litter size and birth weight on Impact of litter size and birth weight on growth performance, carcass

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Federal Department of Economic Affairs FDEA Agroscope Liebefeld-Posieux ALP Research Station ALP Milk and meat production

COST Action 925 meeting

COST Action 925 meetingViborg, DenmarkViborg, Denmark 6

6--7 September 20077 September 2007

J. BéJ. Bérardrard^1-¹^-2², M. Kreuzer, M. Kreuzer²²and G. Beeand G. Bee^*1^*1

Impact of litter size and birth weight on Impact of litter size and birth weight on growth performance, carcass

growth performance, carcass

characteristics, and meat quality in pigs characteristics, and meat quality in pigs

1Agroscope Liebefeld-Posieux, Research Station ALP, 1725 Posieux, Switzerland

2ETH Zurich, Institute of Animal Science, 8092 Zurich, Switzerland

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COST Action 925 meeting Viborg, Denmark 6-7 September 2007

Genetic selection strategy in the last decade Genetic selection strategy in the last decade

increase in the litter size increase in the litter size

•

increased ovulation rate

•

higher embryonic survival

•

without a concomitant improvement of the uterine capacity

intrauterine crowding

when litter size increases:

1.

the uterine blood flow increases

2.

the number of fetuses increases

Result: reduced uterine blood flow (nutrient supply) per foetus

In the last decade a marked increase in the litter size of sows have been reported by many authors.

Genetic selection strategies resulted in increased ovulation rate and higher embryonic survival, without a concomitant improvement of the uterine capacity (Foxcroft, 2007).

Uterine capacity introduces an important concept: Intrauterine crowding

It was proved that when litter size increases, the uterine blood flow increases as well but to a lower extent than the number of fetuses, resulting in a reduced uterine blood flow, and

consequently lower nutrient supply per foetus (Pere and Etienne).

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Litter size and birth weight are related Litter size and birth weight are related

•

• large litter sizelarge litter size

• decreasing average birth weight

• larger variation in birth weight

• higher percentage of low birth weight pigs

•

• low birth weightlow birth weight

• impaired survival rate

• impaired growth performance

• lower lean percentage / greater carcass fatness

• impaired meat quality

Partition of piglets with regard to their birth weight and litter size

Birth weight, kg

< 0.6 0.6 - 0.7 0.7 - 0.8 0.8 - 0.9 0.9 - 1.0 1.0 - 1.1 1.1 - 1.2 1.2 - 1.3 1.3 - 1.4 1.4 - 1.5 1.5 - 1.6 1.6 - 1.7 1.7 - 1.8 1.8 - 1.9 1.9 - 2.0 2.0 - 2.1 2.1 - 2.2 2.2 - 2.3 > 2.4

% of total born

0 2 4 6 8 10 12 14

>= 16 piglets 14 - 15 piglets

<= 11 piglets

For this reason increasing litter size, average birth weight decreases and variation in the birth weight increases

Moreover, as shown in this graph the percentage of low birth weight piglets is higher.

It was proved that low birth weight pigs have not only to impaired growth performance and carcass characteristics but also impaired meat quality than their heavier siblings

Some of these effects might be linked to prenatal events such as myogenesis.

However, no information is available if low birth weight pigs from small litters grow slower, have a fatter carcass and impaired meat quality - as lower water holding capacity or lower tenderness score - than low birth weight pigs from large litters.

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Objectives Objectives

Test the hypothesis that effects of birth weight on Test the hypothesis that effects of birth weight on

• growth performance

• carcass characteristics

• meat quality

differ when pigs originate from small or large litters differ when pigs originate from small or large litters.

Determine whether birth weight of the piglets and/or litter size affects early postmortem proteolysis?

Thus, the first objective of this study was to test the hypothesis that effects of birth weight on growth, carcass characteristics, and meat quality of pigs differ when pigs originated from large or small litters.

Recent studies, suggested that the proteolysis is positively related to the meat quality in pigs.

Therefore, in addition to various meat quality traits, in the present study we also monitored whether birth weight or litter size affects early postmortem proteolysis.

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The 60 Swiss Large White barrows used in this study were originated from 20 litters.

10 litters with 10 or less piglets/litter (small litter) and 10 litters with 14 or more piglets/litter (Large litter). The mummies were also included in the litter size. (runt pigs excluded)

3 piglets were selected per litter: the lightest, heaviest, and the piglets with a birth weight nearest to the average birth weight of the litter were selected.

Pigs were individually penned and They had free access to the same standard starter, grower, and finisher diet.

Individual feed intake and BW was determined weekly.

Experimental design Experimental design

3 piglets/litter were selected

• lightest birth weight (L-BtW)

• birth weight nearest to the average birth weight (M-BtW)

• heaviest birth weight (H-BtW)

60 barrows

(from 20 litters)

10

small litterssmall litters

(≤10piglets/litter)

10

large litterslarge litters

(≥14piglets/litter)

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Growth performance

• ADWG

• ADFI

• Feed efficiency

Proteolysis in the LM and STD

(30 min, 24 and 72 h postmortem)

• Titin and nebulin (SDS-PAGE)

• Integrin and desmin (Western-blot) Carcass characteristic

• Hot carcass weight

• Carcass yield

• Lean meat percentage

• Back fat percentage

• Organ weights

Meat quality traits in the LM and STD

• pH 30 min and 24 h (postmortem)

• Drip loss (after 48h)

• Shear force

Growth performance, carcass characteristics, Growth performance, carcass characteristics, and meat quality

and meat quality

LM= longissimus dorsi muscle

STD= dark portion of the semitendinosus muscle

In addition to growth performance parameters, at slaughter the left carcasses were dissected according to Swiss cutting standards, and the lean meat, backfat percentages and the organs weight were determined.

To investigate meat quality the pH at 30 min and 24 h post mortem, the drip loss percentage after 48 h and shear force values were determined In the longissimus muscle and the dark portion of the semitendinosus muscle

Proteolysis was determined in the both muscles using SDS-PAGE for titin, nebulin and using immunoblot for integrin and Desmin all proteins were determined 30 min, 24 h and 72 h postmortem.

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Birth weight

L-BtW M-BtW H-BtW

kg

1.0 1.2 1.4 1.6 1.8 2.0

2.2 Small litter Large litter LS; P = 0.02 BtW; P < 0.01 LS x BtW; P = 0.07

Growth performance Growth performance

Barrows from large litters were on average lighter than from large litters.

As indicated by the LS BtW interaction, low and medium BtW barrows from large litters tended to be lighter at birth than from small litters. whereas BTW of high BtW barrows not differ between litter size

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Growth performance Growth performance

ADG

L-BtW M-BtW H-BtW

kg/d

0.75 0.80 0.85 0.90

0.95 LS; P =0.47 BtW; P < 0.01 LS x BtW; P = 0.63

Age at slaughter

L-BtW M-BtW H-BtW

d

150 155 160 165 170

175 LS; P =0.95

BtW; P < 0.01 LS x BtW; P = 0.85

Growth performances were no affected by litter size

For this reason in the next graphics only the difference between BtW classes have been reported

As shown in these graphics L-BtW barrowrs grew slower and need more time to reach the market weight which was fixed in our experiment at 105 kg than M- and H- BtW barrowrs.

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ADFI

L-BtW M-BtW H-BtW

kg/d

2.0 2.1 2.2 2.3 2.4

2.5 LS; P = 0.87 BtW; P = 0.04 LS x BtW; P = 0.72

Growth performance Growth performance

Feed conversion ratio

L-BtW M-BtW H-BtW

kg/kg

2.5 2.6 2.7 2.8

2.9 LS; P = 0.82

BtW; P = 0.04 LS x BtW; P = 0.79

Average daily feed intake in the grower-finisher period was lower in low compared to medium or high BtW barrows.

Consequently low birth weight barrows were less efficient than medium or high BtW barrows.

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Carcass yield

L-BtW M-BtW H-BtW

%

78 80 82

84 LS; P = 0.57 BtW; P < 0.01 LS x BtW; P = 0.52

Kidney

L-BtW M-BtW H-BtW

kg

0.28 0.30 0.32 0.34 0.36 LS; P = 0.89

BtW; P < 0.01 LS x BtW; P = 0.26

Carcass characteristics Carcass characteristics

Liver

L-BtW M-BtW H-BtW

kg

1.2 1.3 1.4 1.5 1.6 1.7 1.8 LS; P = 0.64

BtW; P = 0.01 LS x BtW; P = 0.26

Litter size had also no effect on carcass yield or the weight of selected organs, whereas effects of birth weight were found.

The carcass yields were higher in low compared to high BtW barrows, with intermediate values for medium BtW barrows

Liver and kidneys weight were higher in H- than on l- and M-BtW barrows.

Maybe the intestinal trait differ between BtW Classes

Unexpected no differences were found in lean meat and subcutaneous fat percentage

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Omental fat

small litter large litter

%

1.6 1.7 1.8 1.9 2.0 2.1 2.2

2.3 LS; P = 0.06 BtW; P = 0.54 LS x BtW; P = 0.63

Shoulder

small litter large litter

%

11.6 11.8 12.0 12.2 12.4

LS; P = 0.02 BtW; P = 0.60 LS x BtW; P = 0.25

Carcass characteristics Carcass characteristics

However, barrows from small litters had less omental fat and higher percentages of shoulder than barrows from L-litters.

These observations suggested that not only birth weight per se but litter size might also determine carcass characteristics.

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pH_{24 h}

(STD)

L-BtW M-BtW H-BtW

pH

5.5 5.6 5.7 5.8 5.9

6.0 LS; P = 0.85 BtW; P = 0.06 LS x BtW; P = 0.21

pH_{24 h}

(LM)

L-BtW M-BtW H-BtW

pH

5.5 5.6 5.7

5.8 LS; P = 0.16 BtW; P = 0.11 LS x BtW; P = 0.34

Meat quality

Meat quality – – ultimate pH ultimate pH

The initial pH of both muscles was not affected by the litter size not BtW.

By contrast, pH 24h pm was numerically greater in the longissimus muscle of low and medium BtW barrows than in high BtW barrows.

Moreover, The ultimate pH tended to be higher in the semitendinosus muscle of medium compared to low or high BtW barrows.

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Meat quality

Meat quality - - drip loss after 48 h drip loss after 48 h

Drip loss

(STD)

L-BtW M-BtW H-BtW

%

3.0 3.5 4.0 4.5

5.0 LS; P = 0.77 BtW; P = 0.07 LS x BtW; P = 0.60

Drip loss

(LM)

L-BtW M-BtW H-BtW

%

5.0 5.5 6.0 6.5

7.0 LS: P = 0.65 BtW; P = 0.55 LS x BtW; P = 0.28

In these slides results of drip loss determined after 48 h in both muscle is reported.

drip loss in the longissimus muscle was on average about 1% lower in high than low and medium BtW barrows, these differences were not significant because of the large variability within each experimental group.

By contrast in the semitendinosus muscle drip loss tended to be lower in low compared to medium or high BtW barrows.

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Shear force

(STD)

L-BtW M-BtW H-BtW

kg

5.6 5.8 6.0 6.2 6.4 6.6

6.8 LS; P = 0.92 BtW; P < 0.01 LS x BtW; P = 0.34

Shear force

(LM)

L-BtW M-BtW H-BtW

kg

3.8 4.0 4.2 4.4 4.6

LS; P = 0.81 BtW; P = 0.58 LS x BtW; P = 0.45

Meat quality

Meat quality – – shear force shear force

The semitendinosus of barrows of the medium BtW barrows was more tender (lower shear force value) than of the low and high BtW barrows.

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Relative abundance of intact integrin (LM)

0.5 h 24 h 72 h

relative abundance

0.0 0.1 0.2 0.6 0.8 1.0 1.2 1.4 1.6

1.8 Small litter Large litter

LS; P = 0.08 BtW; P = 0.65 LS x BtW; P = 0.33

Large Large litterlitter Small litter Small litter

0.5 h 24 h 72 h

Relative abundance of intact integrin (STD)

0.5 h 24 h 72 h

relative abundance

0.0 0.1 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

1.8 Small litter Large litter

Proteolysis

Proteolysis - - integrin integrin

- -0.310.31 -0.16

-0.07 STD

-0.16 -

-0.340.34 -0.12

LM

72 h 24 h

0.5 h Drip loss

relative abundance of intact integrin

Integrin, is a protein that link the extracellular matrix to the cytoskeleton

It was proved that Degradation of this protein contributes to increase the drip channel and consequently the increase of drip loss

Even if meat quality of LM was not affected by BtW nether by LS

Degradation of the integrin 72 h pm was greater in the longissimus muscle of barrows born from large than from small litters. However, as shown before the differences were not so great to have an impact on drip loss.

No differences were observed in the semitendinosus.

Significant correlations were found between the relative abundance of integrin at 24 h postmortem for the longissimus and at 72 h for the semitendinosus muscle with drip loss.

Our findings are in line with recent results.

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Relative abundance of intact titin (LM)

0.5 h 24 h 72 h

relative abundance

1.0 1.5 2.0 2.5 3.0

3.5 L-BtW

M-BtW H-BtW LS; P = 0.98

BtW; P = 0.06 LS x BtW; P = 0.25

T1 T2

Relative abundance of nebulin (LM)

0.5 h 24 h 72 h

relative abundance

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

1.8 L-BtW

M-BtW H-BtW

LS; P = 0.93 BtW; P = 0.07 LS x BtW; P = 0.12

LL-BtW-BtW MM--BtWBtW

0.5 h 24 h 72 h

H H--BtWBtW

LL-BtW-BtW MM--BtWBtW

0.5 h 24 h 72 h

H H--BtWBtW

Proteolysis

Proteolysis – – titin and nebulin titin and nebulin

† = P< 0.10

* = P< 0.05 0.27*

0.27*

0.05 -0.14

Nebulin

0.22 0.22†† 0.23

0.23†† -0.01

Titin

72 h 24 h

0.5 h relative

abundance

Shear force

In LD

Recent studies have also proved that titin and nebulin degradation are positively related with WHC and tenderness in pork meat

Titin of the longissimus muscle tended to be less degraded at 24 h postmortem in low BtW barrows than in medium and high BtW barrows.

By contrast nebulin was less degraded at 72 h postmortem in high and medium compared to low BtW barrows.

Significant correlations were found between the relative abundance of intact titin 24 h postmortem and intact nebulin 24 and 72 h pm for the longissimus muscle with shear force.

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• The present results confirmed the marked effect of birth weight

on growth performance

- L-BtW barrows grew slower and were less efficient

but only partly

on carcass characteristicsandmeat quality Birth

Birthweightweight

•• LowLow and mediummedium birth weight piglets were lighter in large compared to small litters.

• Impacts on growth performance, carcass characteristics, and meat quality traits were minor.

Litter size Litter size

Conclusions Conclusions

The present results confirmed the marked effect of birth weight in GP

But its impact on the carcass characteristics and pork traits could be only partly demonstrated.

We confirmed that Litter size affected birth weight which was mainly evident in low and median BtW barrows.

The impact of litter size on growth and pork quality were minor, but some tendency showed in this presentation needs further investigation.

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Conclusions Conclusions

• Postmortem proteolysiswas affected by birth weight or litter size

impacts differ between proteins and muscles

• Confirmation of the relationship between intact integrinabundance and drip loss

valid for LM and STD

results suggest that the LM from large litters has a lower water-holding capacity

• Relationship between intact titinand nebulin abundance shear force

Impacts differ between muscles

results suggest that the LM from L-BtW has lower tenderness

Proteolysis Proteolysis

Postmortem proteolysiswas affected by birth weight or litter size but its impacts differ between proteins and muscles

We also confirmed the relationship between integrindegradation and WHC

which seems to be valid not only for the longissimus but also semitendinosus muscle.

The differences between the degradation pattern of integrin in the longissimus muscle of small and large litters and the relationship with the drip loss suggest that the WHC could be affected.

We also proved that BtW affected titin and nebulindegradation and their degradation is positively correlated with tenderness

But their impact differ between muscles

Moreover results suggest that also tenderness in LD could be affected

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Thank you for your attention Thank

Thank youyou forfor your attention your attention