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The Impact of Genetics on
Poultry Production in China
Ning YANG, Ph.D.
Professor and Head
Dept. of Animal Genetics and Breeding
College of Animal Science and Technology
China Agricultural University
Beijing 100094, CHINA
[email protected]
Facts of Poultry Production in China
 Largest poultry population in the world:
15.198 billion birds in stock plus slaughtered
in 2005
 Top egg producer in the world, 28.795 million
tons in 2005, representing 40% of world total
production
 Second largest poultry meat producer in the
world
 A kingdom of waterfowl, with over 70% ducks
and 85% geese in the world
China is a domestication center of
chicken and waterfowls, and has over
5000 yrs history of poultry production
Extensive genetic diversity of Chinese local
chicken breeds
Chicken breeds in Jiangxi
Baier
Kangle
Lingkun
Silkie
Yuganwugu
Chongrenma
Ningdusanhuang
Dongxiangluke
Significant Contribution of Chinese Native Chicken
to the International Chicken Genome Project
2.8 million SNPs were identified in the chicken
Before 1980, the poultry production in China
were mainly in the form of backyard farming,
with vast diversity of native breeds and low
production efficiency
The Age of Genetics
In 1900, Redicovery of Gregor
Mendel’s Genetic Principles
Jay Lush:
Founder of the Science of
Animal Breeding
Genetics has changed world poultry industry
Dr. Paul Siegel’s chicken lines have demonstrated
the power of genetic selection
Great Changes for Broiler Carcass
During Past 20 Years
1985
2005
Chicken meat providers in China
 Broilers  Native chickens  Spent hens
 color-feathered
 slow-growing
 Improved or unimproved
~2.5 billions
>3 billions
1 billion
Broiler Chickens
 Mainly produced in Northern China
 Integrated production system
 Breeder, feedmill and processing
 Company plus household farms
 Better service to farmers
 Branded products
 Export to Japan, Korea et al.
Pipeline for Broiler Production in China
A
B
C
D
X
X
X
X
Pure Lines in USA
GGP
X
X
x 45
X
x 125
GP, 600,000
PS, 25million
CS,~ 3 billion
Major Players for Broiler Breeders in China
 Aviangen
 Arbor Acres
 Ross
 Cobb-Vantress
 Avian
 Cobb 500
 Others
 Hubbard
 Indian River
In certain parts of the World, consumers
have strong preference for quality
chickens with:
 Specific appearance (feather color, shanks,
skin, comb, et al)
 More tasty meat
They are willing to pay higher price for the
so-called quality chickens
Comparisons
 Broilers
 Quality chickens







 Developed from native
chickens
 Specific appearance
 slow-growing (70~120d)
 Poor FCR (2.1~3)
 Tasty and chewy
 Better disease resistance
 Easy to manage
 Higher production cost
Fast growth rate (40d)
Better FCR (1.6)
More meat (Breast 20%)
Soft meat
Less flavor
Need good facility
Hard to manage
 Reasonable cost
Examples for quality chickens
Three-Yellow (3Y) in China
 Yellow is a royal color in China
 Yellow feather
 Yellow skin
 Yellow shank
 Sold as live birds:
 biosecurity risks
 Developing Fast
 Export to Hong Kong
Other examples
 Other types of quality chickens
partridge, black-boned, silkies
Comparisons of Breeding Objectives
 Broilers
 Quality chickens










Growth rate
FCR
Carcass composition
Livability
Breeder performance
Appearance
Meat flavor
Breeder performance
Growth rate
FCR
 More difficult to achieve
Quality Traits
Appearance
so-called packaging traits
 No unique pattern as consumers’ views vary
 Color of plumage, skin or shank: yellow
(buff), red, partridge, and black
 Redness and size of comb
 Sex maturity
Plumage colors
Does plumage color really matter?
Yes!
 Sold mainly in live-bird market.
 Tradition
No!
 We need meat rather than feather.
 No solid evidence that plumage color is
associated with flavor
Genes for feather color
Table 1: genotypes of white-feathered chicken
types
genotypes
notes
Domonant
white
Recessive
white
Recessive
white
Recessive
white
Recessive
white
IICCOOPPAA White leghorn
iiccOOPPAA
iiCCooPPAA
iiCCOOppAA Recessive epistatic pp gene
iiCCooPPaa
Good News: Functional Genes have been identified
PMEL17 for I, and TYR for C
Comb
 Redness and size of comb are important
indicators for sex maturity
 Pullets reaching sexual maturity deposit
sufficient intramuscular and subcutaneous
fat, crucial for enhancing meat flavor
 Pullets with bright red, upright and big comb
are considered first-class quality chickens in
China
Meat Flavor
 Eating quality: both taste and odor
 Content of fatty acids, amino acids, and
nucleotides
 Content of intramuscular and subcutaneous fat
and lipids are crucial for enhancing meat flavor.
 Determined by breeds and marketing age
 The meat flavor can be enhanced by free range
system
Meat Flavor
 IMP:
Inosine-5’-monophosphate
IMP
La
ye
Po
r
ly Xi
mo nh
ut ua
h
Ro
ck
Bi
an
Be
ij
in
gyo
u
5
4.5
4
3.5
3
mg/g 2.5
2
1.5
1
0.5
0
breeds
3
2.5
2
IMP(mg/g) 1.5
AA
Beijing-you
1
0.5
0
28
56
90
days
IMP content of breast
muscle in AA broilers
and Beijing-you
2.05
2
1.95
1.9
IMP(mg/g)
1.85
1.8
1.75
1.7
AA
Beijing-you
28
56
90
days
IMP content of leg
muscle in AA chicken
and Beijing-you
Meat Texture
 Density and diameter of muscle fiber
 Muscle fiber type
Muscle Fibers
P
WP Rock
F2
F2
Silkie
F2
F2
China continues 21th year as top egg
producing country in the world
3500
3000
All eggs
Chicken eggs
总产量(吨)
2500
2000
1500
1000
500
0
1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004
年份
Genetic selection has also significantly changed the
Laying Performance
Rate of Lay(%)
海兰褐20-72周龄产蛋曲线
Egg Production Curve (1990 vs 2005)
100
80
60
40
产蛋率(2005年)
产蛋率(1990年)
20
0
20 25 30 35 40 45 50 55 60 65 70 wks
Dominating Layer Breeders in China
 Hyline ~ 40%
 Hyline Brown
 Hyline W36
 Lohmann
 Lohmann Brown
 Others
 ISA Brown
 Hisex
Application of sex-linked dwarf gene (dw)
 Dw gene was identified in 1959 (Hutt)
 Main phenotypic effect: reduced growth and lower body
weight, leading to better feed efficiency
 dw gene has been cloned and identified as the deficiency of
growth hormone receptor gene
Exon 5 Exon 6 Exon 7 Exon 8 Exon 9
Exon 10
DW
Liver Cell
1775bp
dw
Dwarf layers have been developed in China
and extended widely as an efficient type of
egg layers (FCR~2.05)
Thank you !
Hunting for Blue-eggshell Gene
• Gene O was positioned on Ch.1