ANIHWA call 2: Better bone quality in laying hens

Lead Research Organisation: University of Edinburgh
Department Name: The Roslin Institute

Abstract

Laying hens can produce eggs economically for over a year; a highly digestible protein that has done much to improve world nutrition. However the long period of egg production can come with correlated problems of bone pathology. During egg laying oestrogen induces the formation of medullary bone, a form of calcium storage, in the cavities of the long bones. This bone is highly labile and turns over rapidly during shell formation. The bone forming osteoblasts are almost exclusively active during the formation of medullary bone during lay; however the osteoclasts, which reabsorb the medullary bone for calcium transport to the shell gland, act also on the structural cortical bone. This results in weaker bones (osteoporosis) and susceptibility to bone fracture. Non-cage systems exacerbate the problem with increases in bone fracture and keel bone deformities (>50%). With the demand for economical food unlikely to reduce, solutions to improve bone health are required.

We have shown that there is the genetic potential within commercial pure lines to both lay a high number of eggs and have good bone quality. However the method of assessment of bone quality relies on killing the birds, which precludes subsequent breeding. To counter this, we have developed a number of approaches to discover genetic markers and we have identified a metabolic marker which explains variance in bone quality. Our aim will be to validate these markers and develop a novel phenotypic measurement for bone quality which does not require killing the hen.

The project will build on studies recently completed or under way to detect genetic markers which predict bone quality which have been confined to one line of hens. The study will use quasi static strength measurement, density measurement as well as analytical techniques (infrared spectrometry, 2D X-ray diffraction) to study the chemistry and structure of bone to give a comprehensive insight in to factors defining bone phenotype. These populations, which will be from two types of hen, will be used to validate the markers for use in selection. The populations will also be used to validate the new phenotypic tool (quantitative axial ultrasound) and for the measurement of the blood metabolite which we have shown to be correlated to bone density.

By using an array of approaches we expect to deliver practical solutions to breeders that will allow the genetic potential of laying hens with better bone to be realised.

Technical Summary

The principle barrier to genetic progress in improving bone quality in laying hens is the lack of reliable selection methods. The methods which have been successful experimentally rely on killing birds to make the phenotypic measurements and retrospective selection.
The project has 3 components aimed at delivering markers to use prospectively rather than retrospectively in selection. The project combines the discovery of markers with their validation to ensure confidence in their use.
1) Molecular genetic approaches to define chromosomal loci controlling bone quality and the validation of markers derived from the studies to predict bone quality. To validate genetic markers in other genetic lines we will collect an extensive phenotype database from genetically distinct lines. We will use GWAS data already collected for association with bone strength and identify new markers.
2) The validation of a metabolic marker for its association with bone quality and its potential as a marker for selection. Our genetic and genomic approaches have identified the potential role of a metabolite in predicting bone strength possibly due to an effect on collagen crosslinking. Measurements will be made to establish the measurement of the metabolite and its predictive ability for bone quality.
3) A phenotypic approach to appraise bone quality phenotype in living hens that can be used as a direct assessment of bone quality. The ability of axial transmission of ultrasound in the surface of cortical bone to correlate with incidence of bone breakage will be studied. A fully replicated trial using nutritional treatments known to produce poorer bone quality will be established and the correlation of SOS with measurements of bone quality will be made. In the populations from 1 axial speed of sound sonography (SOS) of tibia and keel in young and end of lay hens will be made to estimate genetic parameters.

Planned Impact

Eggs are an ideal source of nutrients in particular protein and have wide cultural acceptance. They are produced extremely efficiently however there are costs in terms of skeletal health which can represent a welfare issue. As the pressure grows for sustainable intensification the ability of hens to lay for longer is growing. To improve welfare and try and accommodate the conflicting demands it is necessary to find ways to improve by selection the bones of laying hens.
The principle benefit from this research will be methods to select hens to improve bone quality and to gain a greater understanding of the factors which underlie poor bone quality. This will translate in to benefit to the birds themselves and help to address the conflicting demands that agricultural production faces. This should address some of the welfare concerns that have been expressed over the egg production industry .
We have a long history of communication of our work to industry and scientists through scientific conferences including those of the WPSA which typically comprise 50% industry: 50% academia. We will present the work to these and more discipline specific conferences during the project and publish the results in both discipline led and wider industry publications during the project. To ensure wider dissemination appropriate industry days and agricultural events will be used along with a specific meeting organised to target the full range of organisations with an interest in this topic.
There are considerable opportunities to establish transfer of skills in the project. At The Roslin Institute we have a wealth of practical experience in assessing bone quality in chickens. Bob Fleming and Heather McCormack have in the region of 50 years of experience collectively. We already have plans for exchange of personnel between Granada and the Roslin Institute to learn histological and morphological techniques and this will strengthen this link. Similarly opportunities exist with SLU and indeed with Lohmann Tierzucht to transfer expertise. This transfer of knowledge will be critical for the future of research and practical progress on bone quality in laying hens in Europe. SRUC and the Roslin Institute are likely to have a greater alignment in coming years and the area of bone biology is an area where we are likely to be able to bring synergy to the topic. This project will increase the chances that this occurs
 
Description We have completed the practical experiments using ultrasound to assess bone quality. The humerus was found to be the bone of choice for measurement. We were able to obtain good repeatability in all the studies and respectable heritability. In the nutritional experiment we were able to create different levels of bone strength but this did not correlate well with ultrasound velocity through the bone. It now appears that the results showed strong evidence of correlation with the amount of medullary bone when it was present. We have now calculated the genetic correlations in the 2 pedigree populations with all the bone quality traits to see if we can understand what is contributing to the ultrasound trait variation. This has strongly suggested that we are measuring medullary bone quality. Despite some issues that need to be resolved we believe there is potential of the method if it can be optimised for poultry. Detailed studies on the genomic loci controlling bone quality have been successful and a significant amount of variation explained. Some of the loci have been successfully replicated in other lines of hen.
The genetic correlations show contrary to popular belief there is no relation with the persistency of egg production. In one line however it is evident that the onset of egg laying has an effect on bone quality.
Exploitation Route We already have lent the ultrasound machine to allow the breeding company to make additional measurements and evaluate it for selection.
We are part of a newly launched COST action on Keel Bone Damage (KBD) in laying hens. Our experiences in this project will be used to inform the strategies for measuring keel bone damage and improving cage design, nutrition and genetics to minimise KBD.Our experience has led to the funding of a new project to develop a practical x-ray phenotype. The genomic regions highlighted have stimulated investigations into the biology of the how the regions have an effect and in one case a trial on a dietary approach to bone strength.
Sectors Agriculture, Food and Drink

 
Description The project is in collaboration with a poultry breeder, LTZ. They have utilised the ultrasound measurement in some of their studies and they have shown a clear enthusiasm to take up the bone markers and test them on more lines in addition to our studies. We have now won a project from FFAR to develop a phenotype for use in practice.
First Year Of Impact 2015
Sector Agriculture, Food and Drink
Impact Types Societal,Economic

 
Description Accelerating advances in animal welfare
Amount $486,594 (USD)
Funding ID 550396 
Organisation Foundation for Food and Agriculture Research 
Start 04/2018 
End 03/2022
 
Description COST Action
Amount € 3,000 (EUR)
Funding ID CA15224 
Organisation European Cooperation in Science and Technology (COST) 
Sector Public
Country European Union (EU)
Start 04/2016 
End 03/2020
 
Description Flexible Talent Mobility Award collaboration on poultry welfare traits
Amount £8,506 (GBP)
Organisation University of Edinburgh 
Sector Academic/University
Country United Kingdom
Start 01/2018 
End 02/2020
 
Title Better bones 
Description Phenotyped laying hen population with/without DNA for bone quality 
Type Of Material Database/Collection of data 
Year Produced 2015 
Provided To Others? Yes  
Impact Collaboration with colleagues in Germany, Sweden and Spain has resulted in GWAS and other publications 
 
Description Keel bone damage COST action 
Organisation Aarhus University
Country Denmark 
Sector Academic/University 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation Agricultural University Plovdiv
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation French Agency for Food, Environmental and Occupational Health & Safety (ANSES)
Country France 
Sector Public 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation Friedrich Loeffler Institute
Country Germany 
Sector Public 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation Institut de Sélection Animale BV
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation Institute of Animal Biochemistry and Genetics
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation Swedish University of Agricultural Sciences
Country Sweden 
Sector Academic/University 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation University of Bern
Country Switzerland 
Sector Academic/University 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation University of Granada
Country Spain 
Sector Academic/University 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Keel bone damage COST action 
Organisation University of Wageningen
Country Netherlands 
Sector Academic/University 
PI Contribution Ian Dunn is a work group leader and contributed to writing the proposal. We have hosted a number of visits under the scheme and ourselves have taken part in meetings workshops and training activities.
Collaborator Contribution A large number of contributors across Europe with different expertise form the collaboration on keel bone damage. Veterinarians, companies, behaviour specialists and those skilled in measuring damage.
Impact Standardised methodologies, new collaborations, spread of good practice, successful funding applications
Start Year 2016
 
Description Cost action Training School for the histological investigation of avian bone 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Interest in collaboration and potential links with industry.
Year(s) Of Engagement Activity 2019
URL http://www.keelbonedamage.eu/wp-content/uploads/FlyerTrainingSchool.pdf
 
Description How next generation sequencing is helping deliver better bones for laying hens 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact 'What have DNA sequencing technologies ever done for the animal sciences' symposium. Questions on how the information will be used to improve bone health in layers
Year(s) Of Engagement Activity 2015
URL http://www.bsas.org.uk/wp-content/uploads/2014/11/Programme-updated4.pdf
 
Description Improving bone strength in poultry 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Article written by Heather McCormack in Lohmann News on the work to improve bone strength of laying hens by using genetics. Very wide reach
Year(s) Of Engagement Activity 2015
URL http://www.ltz.de/de-wAssets/docs/e-paper/poultry-news-en-10-2015/HTML/index.html#
 
Description OPEN day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact To introduce our work on the sustainability of poultry and egg production to a wider audience. We had a number of activities which introduced the role of the cuticle in preventing bacterial penetration of the egg. For many people this was a revelation. It allowed an opening to discussions on modern farming and to challenge many misconceptions. There was also a lot of hands on opportunities. The event was so successful that we have developed it into a grant for building kits for using at farm visits.
Year(s) Of Engagement Activity 2016
URL http://www.bbsrc.ac.uk/news/people-skills-training/2016/160107-pr-farm-science-at-open-farm-sunday/
 
Description Presentation at European Poultry Genetics Symposium (Tuusula, Finland) Bone 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Talk to audience of the majority of Poultry breeders in the world, Interest from breeders and from other scientists in possible application.
Year(s) Of Engagement Activity 2015
URL http://www.epgs2015.com/program.html
 
Description Presentation at IX European Symposium on Poultry Welfare (Uppsala, Sweden) Bone 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Talk on our work to generate markers which improve bone strength to improve welfare. Much interest has resulted from groups working in this field in Europe
Year(s) Of Engagement Activity 2013
URL http://www.research.ed.ac.uk/portal/en/publications/genetic-markers-for-the-improvement-of-bone-stre...
 
Description Presentation at World Poultry Science UK spring meeting (Chester) Bone 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Identification of genetic markers for the improvement of bone strength in poultry

Interst from industry and welfare organisations
Year(s) Of Engagement Activity 2016
 
Description Working group meeting on the causes of keel bone damage 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact featured a mixture of talks about environmental, genetic, and nutritional causes of keel bone fracture alongside speakers on the etiology and pathology of
fractures. In addition to lectures, the meeting will be organized as a workshop allowing for discussion with planned deliberations intended to produce a review of the field.
Year(s) Of Engagement Activity 2019
URL http://www.keelbonedamage.eu/wp-content/uploads/Flyer-Working-Group-Meeting.pdf