Yesterday, today and tomorrow of the layer breeding industry

Yang Ning ¹ Sun Congjiao ²KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

1.
Chairman of the World Poultry Society (WPSA), Chief Scientist of the National Layer Industry Technology System, Leader of the Expert Group of the National Layer Genetic Improvement Program, Professor, College of Animal Science and Technology, China Agricultural University 2.
Associate Professor, College of Animal Science and Technology, China Agricultural UniversityKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　China's native chicken breeds are rich in resources, but the breeding history is relatively short.
The breeding of layer hens has only gradually gotten on track after the reform and opening up.
After more than 40 years of continuous development, the layer industry has made major achievements.
my country produces about 26 million tons of eggs per year, accounting for nearly 40% of the world's total production, ranking first in the world.
The cultivation and promotion of China's excellent domestically produced layer breeds has broken the foreign monopoly on the source of high-yielding layers, and the current domestic breed's seed supply capacity can meet market demand.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　1.
The development history of laying hensKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　Chickens are currently the largest domesticated animal on the planet, with a long history of domestication.
Darwin proposed in his book "The Variation of Animals and Plants at Home" published in 1868 that domestic chickens originated from the red wild fowl (Gallus gallus), which was also confirmed by early morphological and genetic studies.
On this basis, animal taxonomists further divided the red rock fowl into five subspecies, namely, the named subspecies (Gallus gallus gallus), the southern Yunnan subspecies (Gallus gallus spadiceus), the Java subspecies (Gallus gallus bankiva), and the Indian subspecies.
Subspecies (Gallus gallus murghi) and Hainan subspecies (Gallus gallus jabouillei).
In 2020, Chinese scientists published the latest research results on the origin and domestication of domestic chickens, and found that domestic chickens formally diverged from the southern Yunnan subspecies of red wild chickens 9,500 years ago.
This subspecies is mainly distributed in southwest China, northern Thailand, Myanmar and other regions.
This region should be the domestic chicken domestication center (Figure 1).
After domestication of domestic chickens, with the migration and trade activities of humans, they were first carried to Southeast Asia and South Asia, and then hybridized with other subspecies of red wild fowls there to different degrees.
This gene exchange promoted domestic chickens’ exposure to the new environment.
The rapid adaptation of the animal, and enriches its unique behavior, morphology and reproductive traits.
The breeding history of domestic chickens in the Americas and Australia is much shorter.
In 1493, as Columbus's second passenger to the Americas, he did not reach the Americas.
It was not until 1788 that domestic chickens arrived in Australia with the British First Fleet.
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KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

Figure 1 The southern Yunnan subspecies distributed in southwestern China, northern Thailand, Myanmar and other regions have been domesticated into modern domestic chickensKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

(Drawing based on the results of Wang et al.
, 2020, Cell Research article)KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　(1) The breeding process of foreign layer hensKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　Before the 19th century, independent breeding work was basically not carried out, but there will be certain hybridization between different chicken breeds.
For example, the white cornish chicken, which originated in England, was composed of white Malay chicken and dark chicken around 1890.
Cornish chicken crossbred.
The initial artificial selection of chickens also focused on appearance traits such as body shape and appearance.
For example, the Los Angeles red chicken, which originated in New England in the early days, was a cross between red Malay game cock, brown Laihang chicken and Asian chicken, with complex pedigree and single crown.
, Rose crown, and even bean crown, and with the choice of appearance traits, the Luodao red chicken is generally single crown, which is widely used in the hybrid system of modern laying hens.
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　　At the beginning of the 20th century, with the gradual improvement of people's understanding of the value of chicken production, commercial chicken breeding rose, which led to the essential changes in chicken breeding.
The breeding goal shifted from focusing on body shape and appearance to focusing on economic traits.
This change prompted the transformation of chicken breeding from the experience stage to the modern breeding stage.
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　　For a long time, the main purpose of human raising chickens is to obtain eggs, a food with high nutritional value, and to obtain delicious meat by eliminating laying hens and roosters.
After World War II, the value of broiler production was valued, broiler production began to appear as an independent production department, and layer and broiler breeding began to differentiate (Figure 2).
Laying hen breeding, focusing on the selection and improvement of egg production performance, egg quality, feed utilization and other traits, began to take shape.
The German Roman Group was established in 1932, and the American Hyland Company was established in 1937.
They have more than 80 years of experience in layer breeding.
accumulation.
With the commercial development of layer breeding and the intensified competition in the seed industry market, layer breeding companies continue to merge and integrate.
At present, the global layer breeding companies have been integrated into two groups: German EW Group and Dutch Handk Animal Breeding group.
After nearly a century of development, a globalized and specialized layer breeding industry has been formed, and brilliant achievements have been made.
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KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

Figure 2 Red rock fowl (left) Modern layer (middle, Bai Laihang) Broiler (right, Cornish)KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　(2) The breeding process of China's laying hensKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　China's indigenous chicken breeds have a history of domestication for thousands of years, and the complex and diverse ecological environment and socio-economic conditions have gradually formed a variety of indigenous chicken breeds.
As early as the Zhou Dynasty, the ancestors used chickens to drive away evil spirits.
In ancient China, for a long time, roosters were viewed as cockfighting.
They appreciated the combative characteristics of roosters and gave hens the moral concept of "benevolence" when protecting chickens.
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　　The Chinese people have the custom of raising local chickens for a long time, but the breeding work started late, and specialized modern breeding started after the country listed the breeding of laying hens as a key project in the "sixth five-year plan".
In the past 30 years, my country has used the high-yielding layer breeding materials imported from abroad and the local breed resources of our country to breed domestic layer hens.
Among them, "Jingbai 939" is the earliest supporting line for laying hens cultivated in my country, and it is a supporting line for powder-shell laying hens successfully bred by Beijing Poultry Company in 1993.
In 2000, the Shanghai Xinyang Poultry Breeding Center successfully bred "Xinyang Brown-shell Layers"; in 2004, the College of Animal Science and Technology of China Agricultural University bred the food-saving "Nongda No.
3 Small Layers"; 2009, Beijing Hua Duyukou Poultry Industry Co.
, Ltd.
has successively cultivated new breeds of high-yielding laying hens such as "Jinghong No.
1" and "Jingfen No.
1".
After 2010, the number of varieties cultivated gradually increased.
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　　With the changes in the entire layer breeder industry, similar to the development trend of international layer breeders, domestic layer breeders have been integrated and concentrated in a few breeding companies, such as Beijing Huaduyukou Poultry Industry Co.
, Ltd.
and Beijing Zhongnong Model Layer Breeding Co.
, Ltd.
, among which 5 are selected as national core breeding farms.
While breeding companies are developing towards large-scale and intensive development, domestic varieties have gradually become the mainstream.
In recent years, the market share of domestic breeds has continued to increase (Figure 3).
In 2006, domestic breeds and imported breeds accounted for about 31% of my country’s ancestral laying hens.
By 2019, 490,200 sets of ancestors were added.
Among them, domestically cultivated varieties accounted for 81.
7%.
The laying hen industry in my country has basically got rid of the dependence on introduced breeds, and the seed production capacity of the domestically produced ancestors can fully meet domestic demand.
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KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

Figure 3 Proportion of the ancestors of domestic and imported layer breeds from 2006 to 2019 (China Animal Husbandry Association)KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　2.
Development of modern layer breeding at home and abroadKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　(1) Foreign developmentKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　The international modern breeding of laying hens started in the 1930s and 1940s.
The most important aspect of laying hen breeding is the selection and improvement of laying performance.
Laying performance is affected by many factors, including age at the start of laying, laying intensity, continuity of laying, and laying cycle.
In order to realize modern layer breeding, it is necessary to be able to measure the individual egg production of individual chickens.
The invention of the self-closing laying box and the application of individual single cage breeding technology have realized the individual record of the number of eggs laid, and the large-scale incubator has solved the incubation and hatching.
The problem is that it is easy to establish a pedigree, and it also avoids nesting (also called "brooching", which is a kind of maternal behavior in poultry).
It is specifically manifested as a period of time after laying eggs, the body temperature rises, the coat is fluffy, the eggs are nested, and the laying is stopped.
Egg), which improves egg production.
In the 1940s, heterosis was fully utilized in the breeding of laying hens, and the method of repetitive cross-breeding was also implemented.
During this period, the development of biostatistics promoted the application of selection index method and partial regression coefficient method in layer breeding, which greatly promoted the work of layer breeding.
With the development of classical quantitative genetics, family selection and BLUP breeding value selection have entered modern layer breeding.
With the application of the latest genome selection technology, the technical level of layer breeding has reached a new height.
In addition, the research and use of vitamin D at the beginning of the 20th century provided important nutritional conditions for breeding chicken houses.
The application of the chick self-separation technology (using the phenotype controlled by the sex chromosomes to show different characteristics in different sexes, such as feather color and feather speed, etc.
), reduces the number of roosters raised, makes full use of breeding equipment, and speeds up breeding pace.
The implementation of sanitation and anti-epidemic measures ensured the health of the population, and only then has it slowly realized the modern industrialized laying hen breeding model (Figure 4).
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KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

Figure 4 Free-range chicken farms and modern caged chicken houses in the 1920s in the United StatesKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　At present, the main international laying hen breeds have formed many brands, mainly including Roman, Hyland, Nick, etc.
of EW Group, as well as Isa, Hessex, Bovans, Deka, Chevron, etc.
of Handke Group.
Warren, Babcock and other brands.
Each brand is subdivided into multiple series, including brown shell, powder shell, white shell, etc.
, to meet the diversified needs of customers in different regional markets.
The main international consumption of brown and white shell eggs (ratio is about 6:4), while the United States mainly consumes white shell eggs (about 90%), China's consumption is more diversified, including brown shell (55%), flour Shell (43%), white shell (1%) and green shell (1%).
The scale and market share of international layer breeding companies are highly concentrated.
Today's international (except China) layer market is mainly the competition between the products of Hyland, Roman and Yisha Breeding Company, which accounts for 40% of the world's layer stock.
The Chinese market is mainly the competition between the breeds under the German EW Group and the domestically produced “Jing” series of layer breeds independently cultivated by Beijing Huadu Yukou Poultry Co.
, Ltd.
The market share of high-yielding layer breeders is each accounted for About 45%.
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　　(2) Domestic developmentKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　Since the reform and opening up, the breeding work of laying hens in my country has achieved remarkable results.
After more than 40 years of hard work, the scientific and technological strength of layer breeding has been significantly enhanced, and a good breed breeding system with enterprises as the main breeding body has basically taken shape.
A number of modern breeding farms and expansion bases have been established (Figure 5), which has contributed to the development of the layer industry.
Important contribution.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

Figure 5 Intelligent determination and incubation hall of modern breeding farmKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　Over the past 40 years, my country has used imported high-yielding layer breeding materials (such as Bailaihang, Luodao Red, Luodao White and other standard breeds) and local breed resources in my country to cultivate specialized strains with outstanding advantages, using two-line or three-line The department's supporting model efficiently organizes the cultivation of new varieties.
As of the end of 2020, my country has independently cultivated 23 new breeds or supporting lines of laying hens approved by the National Animal and Poultry Genetic Resources Committee.
Among them, there are 13 high-yielding layer breeds (Table 1), most of which lay more than 310 eggs at 72 weeks of age.
The production performance is at or close to the level of similar foreign breeds.
It is suitable for the breeding environment in China and has a large number of promotion; local special eggs There are 10 chicken breeds (Table 2), all of which are bred on the basis of local chicken resources in China.
The production performance varies greatly.
The number of eggs laid at 72 weeks is between 220-280, although the number of eggs is relatively low.
, But the egg quality is better, the egg yolk ratio is large, the egg white is sticky, the egg shell is shiny, and the egg weight is moderate.
It is more in line with the traditional consumption habits of Chinese residents and meets the consumer needs of diversified markets.
In addition to eggs, the economic benefits of eliminating old hens from local characteristic laying hens are also higher, which is an important factor in promoting the development of local characteristic laying hens.
At present, the market share of domestically produced varieties has reached 50%, of which high-product varieties accounted for 80% and local characteristic layer hens accounted for 20%.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　The research and development of laying hen breeding technology in my country has reached the international level.
The "Fengxin No.
1" SNP chip jointly developed by China Agricultural University and Beijing Huaduyukou Poultry Industry Co.
, Ltd.
has been substantively applied in the genome selection work of some domestic breeding companies, opening the era of domestic genome selection breeding .
Secondly, molecular marker-assisted selection technology has been widely used in the breeding of domestic breeds.
For example, the SLCO1B3 gene that controls the green shell traits is applied to the breeding of green shell laying hens; the DW dwarf gene is used in the breeding of dwarf and low-cost laying hens; The detection method of fishy susceptibility alleles is applied to the breeding of high-yielding layers; the mutation sites that inhibit the dominant white feather gene are excavated, and the red feather powder shell layer breeds are bred.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　3.
Problems and gapsKSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　Compared with developed countries, there is still a certain gap in laying hen breeding in my country.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　1.
The basic work of breeding needs to be improved.
The development and application of automated, intelligent and precise measurement equipment is insufficient, the measurement time is short, and the population is small, and the work of epidemic disease purification needs to be strengthened.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　2.
The transformation and application of new breeding technologies need to be strengthened.
The selection and breeding of egg quality, feed conversion efficiency, disease resistance and other traits are progressing relatively slowly, and the application of genome selection technology is lagging behind.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　3.
The brand building of domestic varieties needs to be further improved.
The production performance of domestic excellent laying hen breeds has reached the international advanced level, but there is still a gap between some technical service teams and the promotion service level, and the brand promotion needs to be improved.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　4.
The integration of science and technology needs to be deepened.
Breeding companies generally lack high-level and experienced breeding talents, and the substantive interest linkage mechanism of science and technology companies is not perfect.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　4.
Development direction of the "14th Five-Year Plan"KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　In the future, we will continue to implement the national laying hen genetic improvement plan, insist on independent innovation, continuously improve the ability of independent innovation of breeds, and comprehensively improve the development level of my country’s laying hen breeding industry.
KSJ China Feed Industry Information Network-Based on feed, serving animal husbandry

　　1.
To build a world-class core breeding leading enterprise.
Focus on supporting layer breeding companies with good breeding foundation, strong innovation ability and high market share, integrate resources, talents, and technical elements to create an internationally competitive layer breeding group; encourage breeding companies to build modern breeding scientific research platforms, and promote Enterprises and scientific research institutions jointly build high-standard laboratories, breeding research and development centers, and breeding bases.
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　　2.
Strengthen the commercial breeding system.
Improve the in-depth integration mechanism of science and technology, establish a team of high-quality talents suitable for commercialization and efficient breeding, cultivate a number of new breeds of layer hens with strong international competitiveness, and support Chinese layer hen breeds to go abroad in accordance with the law and participate in international competition.
.
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　　3.
Consolidate the national breeding system for laying hens.
Integrate project funds, increase support for infrastructure, performance measurement, and intelligent breeding of improved seed breeding bases, establish a number of high-standard, high-level breeding bases for improved seed breeding, and improve the supply of high-quality seed sources.
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　　4.
Upgrade the national layer hen superior breed support technology system.
Laying hens will be included in the national joint research plan for improved breeds of livestock and poultry, new breeds will be cultivated, and a batch of advanced applicable technologies will be developed.
Improve the performance measurement system, study the measurement and breeding methods of new traits, and accelerate the application of new technologies such as genome selection.
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