The interaction of gender and MC4R genotype on feed intake and lean meat gain in growing finishing pigs

A. Van den Broeke, M. Aluwé,  F. TuyttensS. Janssens, A. Coussé, N. Buys, S. Millet

Institute for Agricultural and Fisheries ResearchAnimal Sciences Unit

www.ilvo.vlaanderen.be

EAAP 2014

IntroductionMelanocortin 4 receptor: (Asp298Asn polymorphism) 

→ association studies→ increased daily gain and lower lean meat content in pigs 

Rodents and human:  feed intake Effect on feed intake in pigs not well studiedAim: • effect on DFI• effect on  DG and DLMG• effects on carcass quality • effect on FCR

Function MC4R

Function MC4R in rodents and humans:• part of leptin‐melanocortin pathway

• information adipose  ssue → hypothalamic responses

• changes in feed intake andmetabolic rate 

Leptin-melanocortin pathway

Leptin

ARC

Anorexigenic signalDecreased feed intakePVN

AgRP

AgRP

MC4R

MC4RMC4R

MC4R

MC4R

AgRP α-MSH

α-MSH

Other sites

AgRP

AgRP

AgRP

MC4R

MC4R

MC4R

MC4R MC4R

α-MSH

α-MSHMC4R

α-MSH

Increased energy expenditure

‐

LEPR

LEPR

LEPR

LEPR

α-MSHMC4R

Experimental design• interventional study• offspring of a commercial cross (hybrid sow X Piétrain) • Homozygous littermates of AG sow x AG sire

n EM G

AA 6ˣ11 6ˣ11

GG 6ˣ11 6ˣ11

Performances

• ad libitum three phase‐ feeding• 20‐40 kg: NEv: 9.6 MJ/kg; dLYS: 9.5 g/kg• 40‐70 kg: NEv: 9.4 MJ/kg; dLYS: 8.5 g/kg• 70‐110 kg: NEv 9.2 MJ/kg; dLYS: 7.5 g/kg

• Weekly data collection• individual weight• feed consumption per pen

• Slaughter: intended average live weight of 110 kg

Carcass quality

Carcass quality (n= 237)Individual data collection in slaughterhouse

• muscle thickness• backfat thickness• meat percentage

Performances: DFI

Gender P=0.528

Genotype P=0.001

1700

1800

1900

2000

2100

2200

g

Average daily feed intake (mean ± s.d.)

EM AA EM GG G AA G GG

n=44 pens

Performances: ADG

Gender P<0.001

Genotype P<0.001

GenderˣGenotype P=0.044

700725750775800825850875900925

g

Average daily gain

EM AA EM GG G AA G GG

bb

n=254 animals

a

b

Performances: DLMG

Gender P=0.051

Genotype P=0.544

n=254 animals

340

360

380

400

420

440

460

g

Daily lean meat gain

EM AA EM GG G AA G GG

Carcass quality

• No gender x genotype interaction for any carcass trait

0

5

10

15

20

mm

Back fat thickness

EM AA EM GG G AA G GG

Carcass quality: fat

CGM device

Gender P=0.875

Genotype P<0.001

60

61

62

63

64

65

66

67

%

Meat percentage

EM AA EM GG G AA G GG

Carcass quality

Gender P=0.281

Genotype P<0.001

2.2

2.3

2.4

2.5

2.6

2.7

2.8

g/g

Feed conversion ratio

EM AA EM GG G AA G GG

Gender P<0.001

Genotype P=0.570

Performances: FCRn=44 pens

• ↑ DG of AA animals due to↑ DFI• No effect on DLMG • Extra DG: extra fat deposition

• No effect on FCR although AA lower lean meat percentage:  • faster growth AA animals: relatively lower maintenance requirements

• decreased energy expenditure??

Discussion

Leptin-melanocortin pathway

Leptin

LEPR

LEPR

ARC LEPR

LEPR

Anorexigenic signalDecreased feed intake

α-MSH

PVN

AgRP

AgRP

MC4R

MC4RMC4R

MC4R

MC4R

MC4R

AgRP α-MSH

α-MSH

Other sites

AgRP

AgRP

AgRP

MC4R

MC4R

MC4R

MC4R MC4R

α-MSH

α-MSHMC4R

α-MSH

Increased energy expenditure

‐

Leptin-melanocortin pathway

Leptin

ARC

Anorexigenic signalDecreased feed intake

α-MSH

PVN

AgRP

AgRP

MC4R

MC4RMC4R

MC4R

MC4R

MC4R

AgRP α-MSH

α-MSH

Other sites

AgRP

AgRP

AgRP

MC4R

MC4R

MC4R

MC4R MC4R

α-MSH

α-MSHMC4R

α-MSH

Increased energy expenditure

‐

??

??LEPR

LEPR

LEPR

LEPR

AA GG

Conclusions

↑ ADFI ↓

↑ ADG, EM ↓

↓ Meat percentage ↑

↑ Back fat thickness

↓

Thank you for your attention!