The Impact of Genetics on Poultry Production in China

Ning YANG, Ph.D.

Professor and HeadDept. of Animal Genetics and BreedingCollege of Animal Science and TechnologyChina Agricultural University

Beijing 100094, CHINA

nyang@cau.edu.cn

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 JiangxiChicken breeds in Jiangxi

Ningdusanhuang

Baier

DongxianglukeYuganwugu

SilkieLingkun

ChongrenmaKangle

Significant Contribution of Chinese Native Chicken Significant Contribution of Chinese Native Chicken to the International Chicken Genome Projectto 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

1985

2005

Great Changes for Broiler Carcass During Past 20 Years

Chicken meat providers in China Broilers Native chickens

color-feathered slow-growing Improved or unimproved

Spent hens

~2.5 billions >3 billions 1 billion

Broiler Chickens Mainly produced in Northern China

Integrated production systemBreeder, feedmill and processing Company plus household farmsBetter service to farmersBranded productsExport to Japan, Korea et al.

X

A B C D

X X X

XX

X

x 125

x 45

GP, 600,000

PS, 25million

CS,~ 3 billion

Pipeline for Broiler Production in China

Pure Lines in USA

GGP

Major Players for Broiler Breeders in China Aviangen

Arbor AcresRoss

Cobb-VantressAvian Cobb 500

OthersHubbard 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 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

Broilers 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 Quality chickens

Appearance Meat flavor Breeder performance Growth rate FCR

More difficult to achieve

Broilers

Growth rate FCR Carcass composition Livability Breeder performance

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 colorTable 1: genotypes of white-feathered chicken

types genotypes notes

Domonant white IICCOOPPAA White leghorn

Recessive white iiccOOPPAA

Recessive white iiCCooPPAA

Recessive white iiCCOOppAA Recessive epistatic pp gene

Recessive white 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:

00. 51

1. 52

2. 53

3. 54

4. 55

mg/ g

breeds

I MP

Inosine-5’-monophosphate

0

0. 5

1

1. 5

2

2. 5

3

I MP(mg/ g)

28 56 90

days

AABei j i ng- you

1. 7

1. 751. 8

1. 851. 9

1. 952

2. 05

I MP(mg/ g)

28 56 90

days

AABei j i ng- you

IMP content of breast muscle in AA broilers and Beijing-you

IMP content of leg muscle in AA chicken and Beijing-you

Meat Texture Density and diameter of muscle fiber

Muscle fiber type

Muscle Fibers

PP

FF22 FF22

WP RockWP Rock SilkieSilkie

FF22 FF22

China continues 21th year as top eggproducing country in the world

0

500

1000

1500

2000

2500

3000

3500

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

年份

()

总产

量吨

Al l eggsChi cken eggs

Genetic selection has also significantly changed the Laying Performance

Egg Production Curve (1990 vs 2005)

Dominating Layer Breeders in China

Hyline ~ 40%Hyline BrownHyline W36

LohmannLohmann Brown

OthersISA Brown Hisex

1775bp1775bp

DWDW

dwdw

Exon 5Exon 5 Exon 6Exon 6 Exon 7Exon 7 Exon 8Exon 8 Exon 9Exon 9 Exon 10Exon 10

Liver Cell

Dw gene was identified in 1959 (Hutt)Dw gene was identified in 1959 (Hutt)

Main phenotypic effect: reduced growth and lower body Main phenotypic effect: reduced growth and lower body weight, leading to better feed efficiencyweight, leading to better feed efficiency

dwdw gene has been cloned and identified as the deficiency of gene has been cloned and identified as the deficiency of growth hormone receptor genegrowth hormone receptor gene

Application of sex-linked dwarf gene Application of sex-linked dwarf gene ((dwdw))

Dwarf layers have been developed in China and extended widely as an efficient type of egg layers (FCR~2.05)

Thank you !Thank you !

Hunting for Blue-eggshell Gene

• Gene O was positioned on Ch.1