Benefits of genetics and genomic in improvement of poultry breeds throughout the years.

1. ‫الرحيم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬
Genetic Improvement Programs in
Poultry Breeds.
 Presented by : MOHAMED ADINANI & ABUBAKAR MOHAMMED AHMAD
 Supervised by : Dr. AMANI ZEINELABDEEN

2. CONTENT:
 Introduction.
 Selection of Chickens.
 Genetics of Disease Resistance in Poultry.
 Genetic Improvement in Broilers.
*Genetic Selection in Broilers.
*Performance Traits of Economic Importance.
 Genetic Improvement in laying Hens.
*Breeding Goals for layers.
*Areas of Improvement.
 Conclusion.
 References.

3. Introduction :
 After humans observed the benefits they could obtain from domestic animals, they continued to
maintain their influence on domesticated animals with more and more sophisticated technologies as
time goes, as seen, for example, with the method of genomic selection currently used.
 Subsequent to breed standardization, specialized lines have been developed for a high growth rate or
egg production, by applying breeding goals and modern methods of selection relying on the
quantitative genetics theory. New breeds or lines can still be created by crossing the existing breeds
or by biotechnology, with transgenesis or, more recently, genome editing.
 The quantitative genetics was applied with a high efficiency to industrial chicken breeding. Very high
performance levels have been reached for growth or for egg laying in highly specialized lines which
are kept in well controlled environments.

4. Selection of chicken :
 Domestication is a continuous process of interaction between humans and the target animal.
Further differentiation of domestic birds has taken place as a result of new mutations, drift and
adaptation to local conditions. In particular, plumage color mutations and morphological mutations
have been accumulating, following domestication of all bird species.
 The selection and breeding program in poultry has been changing as per the knowledge gained
and the needs. The individual poultry flocks were evaluated and after retaining the selected birds,
which transformed the poultry breeding for production of the high-yielding modern layer and
broiler strains.
 The purebreds were also replaced by commercial hybrids as terminal cross as well the specialized
egg and meat type birds replaced dual type birds.

6.  Layer :
 for layer, the objectives primarily is “To obtain maximum number of saleable eggs per hen housed at
low feed cost per egg and the eggs should have optimal internal and external qualities.
 Stock should have low mortality and high adaptability to different environments. Layer breeders apply
selection to improve over 30 traits important for commercial egg production. Breeders today select for
the age at sexual maturity, the rate of lay, livability, egg weight, body weight, feed conversion, shell
color, shell strength, albumen height, egg inclusions (blood and meat spots), and temperament.
 Broiler:
 for broilers, selection strategies concentrate on rapid growth and carcass traits. The most practiced
strategy for broiler is “selection at commercial weight,” which employs selection at a weight that
matches the market weight and the age at selection becomes progressively earlier as growth potential
increases.
 The other two strategies are the selection at a commercial age and multi-stage selection. Different
breeding and selection technologies at different period of time were employed for the genetic
improvement of poultry. Breast muscle weight, meat quality, and FCR are major traits; in addition to
these, thrust is also being given on skeletal abnormalities, metabolic disorders and welfare. In
developing or maintaining a strain of broilers, geneticists must consider a balance of characteristics
related to growth versus reproduction .

7. Genetics of Disease Resistance in Chicken:
 Worldwide egg and poultry meat production is close to 73 million tons and 100 million tons
respectively. Despite such an increase in the growth of poultry industry, this industry is consistently
threatened by various diseases, including those caused by viral, bacterial and parasitic infections.
These diseases can lead to substantial economic losses.
 Chicken have developed different responses to counter these diseases. These responses include
immunological and genetic responses of the poultry. The genetic interaction between the host and
the pathogen is a key factor in deciding the disease resistance.
 Current knowledge of chicken immunogenomics such as the quantitative trail locus mapping of the
combination of DNA variations, immune response by the host and the transcriptome can be used to
identify disease resistant genes. Disease resistant genes are those encoding antibodies, microRNA
and other materials that help the host resist the damage caused by pathogens.

8.  For effective control of different infectious diseases in chicken, the best and most reliable approach is
the improvement of the genetics of disease resistance.
 Enhancement of immune responses may lead to improved efficacy of vaccines and disease resistance,
hence reduction in drug residues in the food products.
 Introducing new technologies that will help us to unveil the underlying transcriptional and other
molecular mechanisms for disease resistance in chicken is a promising tool to improve genetic
resistance for diseases.
 Technologies that aid in identification of disease resistant genes include next generation sequencing,
microarray analysis, RNA sequencing and high density SNP genotyping.
 The development and distribution of disease resistant poultry flocks represents a proactive strategy for
controlling diseases in chicken an complements current approaches for disease control by drugs and
vaccination.

10. Genetic improvement in broiler
 Since the 2000s, poultry has been the fastest-growing meat product in the world, with an average
annual growth rate higher than 3%. It has become the most produced meat in the world since 2017
and is expected to account for almost half of the total growth in meat production in the coming
decade.
 This expansion of poultry production, has been concomitant with the emergence of industrial poultry
production based on the use of highly productive genetic strains and the optimization of breeding
and sanitary conditions as well as inputs (particularly food). while feeding programs have evolved in
order to cover the high nutritional requirements of the modern hybrids.

11. 1- genetic selection in broiler :
 Intense genetic selection for economically important traits like body weight, growth rate, feed
efficiency, and those associated with carcass-processing characteristics have been instrumental in
increasing productivity and efficiency of the broiler industry.
• Over the past 20 years , poultry breeding companies have placed considerable selection pressure on
breast meat yield. This, in turn, has increased overall eviscerated body weight of broilers.
Genetic improvement is expected to result in broilers reaching a 2.34 kg market-ready body weight in less
than 29 d by the year 2034.

12. 2-Performance traits of economic importance :
 A study conducted in Brazil with approximately 29, 000 broilers reported heritability and correlation
coefficients of some traits of economic importance for the broiler industry .
 Among these traits, body weight at 38 d of age and abdominal fat content had the greatest
heritability with 0.40 and 0.53, respectively. Meanwhile, feed intake and feed conversion ratio had the
lowest heritability with 0.20 and 0.16.
 Additionally, body weight at 42 d of age was highly correlated with feed intake, eviscerated body
weight, and leg weight. In a similar manner, feed intake was also highly correlated with breast weight
and abdominal fat content.

15. Genetic improvements in laying hens.
 Egg production has been improved consistently since the late 1930s, and the industry
continues to improve the efficiency of production by at least 1% per year (Hy-Line and
industry data).
 This requires the simultaneous improvement of multiple traits, including egg number,
egg size, liveability, persistency, mature body weight and Liveability. A major component
of this progress has been selection for improved robustness and disease resistance.
 United States industry estimates are that egg number to 60 weeks has improved by more
than one egg per year and the feed conversion ratio (FCR) is improving by 0.01 per year.

16. Fig; Genetic progress in Layers throughout the years.

17. Breeding goals for layers.
 All breeding plans for commercial breeding companies have one major objective in
common: to increase the genetic potential of the stock to produce saleable, high quality
products at minimum cost in a given production system.
 Breeders of egg-type chickens concentrate on four major objectives. They are:
 Maximum number of saleable eggs per hen housed.
 Low feed cost per egg or per kg egg mass.
 Optimal internal and external egg quality.
 Low mortality and high adaptability to different environments.

18. AREAS OF IMPROVEMENT IN LAYERS:
 1- Feed Consumption Rate (FCR).
 2- Persistency of Egg Production.
 3- Egg Quality.

19. 1. Feed Conversion Rate. (kg feed per kg egg
mass)
 The most important influence of genetics on the development of the poultry industry
has been the improvement in FCR. Feed expenses are the main cost in egg production
and account for more than 60% of the production costs in laying hens.
 Sustained improvements in FCR have an impact on the industry through the requirement
for less feed per unit weight of product. This affects the demand for animal feed
resources (mainly grains) and ultimately the cost of production.
 The most commonly used criteria for feed efficiency in laying hens are daily feed intake
per hen, feed intake per egg, feed conversion (kg feed per kg egg mass) and egg income
minus feed cost.

20. CONT…
 Comparing modern egg layers with those available 30 years ago shows that in 1975 it
took 2.4 tons of feed to produce each ton of eggs whereas today it takes 1.9 ton of feed
to produce 1ton of eggs. (Hy-Line and FAO:
http://faostat. fao.org).
 Today at least 115 million tons of feed is used to produce eggs. Using the 1975
genotypes to produce all of today’s eggs would require 144 million tons of feed, an
increase of 26%.

22. 2. PERSISTENCY OF EGG PRODUCTION
 The persistency of egg production: is the number of weeks during which a level of
constant production of eggs is maintained. (usually measured after the peak)
 breeding programs are particularly focusing on in improving laying persistency and egg
quality at the end of the laying cycle.
 A typical egg production curve for a flock increases rapidly during the first eight or nine
weeks of production, maintains a constant production for a certain time, and then
decreases slowly.
 A hen with a flatter egg production curve is considered to be more persistent than a hen
with a curve that decreases rapidly after peak production.
 Thus hens that are more persistent can be more desirable because the producer can
depend on a longer period of constant production.

23. Fig; Normal egg production curve. (age of birds against flock production %) .

24. 3. BREEDING FOR EGG QUALITY.
 Egg quality traits are of utmost importance in layer breeding programs due to their
effect on profitability in the egg production industry.
 Breeding programs are used to improve both internal and external characteristics of eggs
in including (egg weight, eggshell thickness, albumen height and egg shape index)
Table; Quality of eggs of three strains of layer (Silversides et al., 2006).

25. CONCLUSION:
 Advances in molecular biology and genetic sciences have contributed
to new techniques for selection in animal breeding, which lead to the new
revolution of breeding in animal science and especially in Poultry field.
 Accurate date recording in different environment, combined with
genomic data, will make selection faster and more accurate, and enhance
progress in both layers and broilers (in feed conversion, meat quality, egg
quality, livability, behaviors and other traits).

26. REFERENCES
 A. K. Thiruvenkadan. (2010). Layer breeding strategies. World’s Poultry
Science Journal, Vol. 66, September 2010.
 J.C. McKay. (2009). Biology of Breeding Poultry. Poultry Science Symposium
Series, Vol. 29.
 Samuel E. Aggrey, Huaijun Zhou, Michele Tixier–Boichard, and Douglas D.
Rhoads. (2020). Advances in Poultry Genetics and Genomics.
 W.M. Munir and S.E. Aggrey. (2003). Poultry Genetics, Breeding, and
Biotechnology
 Xiaojun Liu. (2018). Application of Genetics and Genomics in Poultry
Science.
 FAO: http://faostat. fao.org).
 https://lohmann-breeders.com