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Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus

BACKGROUND: A host can adopt two response strategies to infection: resistance (reduce pathogen load) and tolerance (minimize impact of infection on performance). Both strategies may be under genetic control and could thus be targeted for genetic improvement. Although there is evidence that supports...

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Autores principales: Lough, Graham, Rashidi, Hamed, Kyriazakis, Ilias, Dekkers, Jack C. M., Hess, Andrew, Hess, Melanie, Deeb, Nader, Kause, Antti, Lunney, Joan K., Rowland, Raymond R. R., Mulder, Han A., Doeschl-Wilson, Andrea
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5396128/
https://www.ncbi.nlm.nih.gov/pubmed/28424056
http://dx.doi.org/10.1186/s12711-017-0312-7
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author Lough, Graham
Rashidi, Hamed
Kyriazakis, Ilias
Dekkers, Jack C. M.
Hess, Andrew
Hess, Melanie
Deeb, Nader
Kause, Antti
Lunney, Joan K.
Rowland, Raymond R. R.
Mulder, Han A.
Doeschl-Wilson, Andrea
author_facet Lough, Graham
Rashidi, Hamed
Kyriazakis, Ilias
Dekkers, Jack C. M.
Hess, Andrew
Hess, Melanie
Deeb, Nader
Kause, Antti
Lunney, Joan K.
Rowland, Raymond R. R.
Mulder, Han A.
Doeschl-Wilson, Andrea
author_sort Lough, Graham
collection PubMed
description BACKGROUND: A host can adopt two response strategies to infection: resistance (reduce pathogen load) and tolerance (minimize impact of infection on performance). Both strategies may be under genetic control and could thus be targeted for genetic improvement. Although there is evidence that supports a genetic basis for resistance to porcine reproductive and respiratory syndrome (PRRS), it is not known whether pigs also differ genetically in tolerance. We determined to what extent pigs that have been shown to vary genetically in resistance to PRRS also exhibit genetic variation in tolerance. Multi-trait linear mixed models and random regression sire models were fitted to PRRS Host Genetics Consortium data from 1320 weaned pigs (offspring of 54 sires) that were experimentally infected with a virulent strain of PRRS virus to obtain genetic parameter estimates for resistance and tolerance. Resistance was defined as the inverse of within-host viral load (VL) from 0 to 21 (VL(21)) or 0 to 42 (VL(42)) days post-infection and tolerance as the slope of the reaction-norm of average daily gain (ADG(21), ADG(42)) on VL(21) or VL(42). RESULTS: Multi-trait analysis of ADG associated with either low or high VL was not indicative of genetic variation in tolerance. Similarly, random regression models for ADG(21) and ADG(42) with a tolerance slope fitted for each sire did not result in a better fit to the data than a model without genetic variation in tolerance. However, the distribution of data around average VL suggested possible confounding between level and slope estimates of the regression lines. Augmenting the data with simulated growth rates of non-infected half-sibs (ADG(0)) helped resolve this statistical confounding and indicated that genetic variation in tolerance to PRRS may exist if genetic correlations between ADG(0) and ADG(21) or ADG(42) are low to moderate. CONCLUSIONS: Evidence for genetic variation in tolerance of pigs to PRRS was weak when based on data from infected piglets only. However, simulations indicated that genetic variance in tolerance may exist and could be detected if comparable data on uninfected relatives were available. In conclusion, of the two defense strategies, genetics of tolerance is more difficult to elucidate than genetics of resistance. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12711-017-0312-7) contains supplementary material, which is available to authorized users.
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spelling pubmed-53961282017-04-20 Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus Lough, Graham Rashidi, Hamed Kyriazakis, Ilias Dekkers, Jack C. M. Hess, Andrew Hess, Melanie Deeb, Nader Kause, Antti Lunney, Joan K. Rowland, Raymond R. R. Mulder, Han A. Doeschl-Wilson, Andrea Genet Sel Evol Research Article BACKGROUND: A host can adopt two response strategies to infection: resistance (reduce pathogen load) and tolerance (minimize impact of infection on performance). Both strategies may be under genetic control and could thus be targeted for genetic improvement. Although there is evidence that supports a genetic basis for resistance to porcine reproductive and respiratory syndrome (PRRS), it is not known whether pigs also differ genetically in tolerance. We determined to what extent pigs that have been shown to vary genetically in resistance to PRRS also exhibit genetic variation in tolerance. Multi-trait linear mixed models and random regression sire models were fitted to PRRS Host Genetics Consortium data from 1320 weaned pigs (offspring of 54 sires) that were experimentally infected with a virulent strain of PRRS virus to obtain genetic parameter estimates for resistance and tolerance. Resistance was defined as the inverse of within-host viral load (VL) from 0 to 21 (VL(21)) or 0 to 42 (VL(42)) days post-infection and tolerance as the slope of the reaction-norm of average daily gain (ADG(21), ADG(42)) on VL(21) or VL(42). RESULTS: Multi-trait analysis of ADG associated with either low or high VL was not indicative of genetic variation in tolerance. Similarly, random regression models for ADG(21) and ADG(42) with a tolerance slope fitted for each sire did not result in a better fit to the data than a model without genetic variation in tolerance. However, the distribution of data around average VL suggested possible confounding between level and slope estimates of the regression lines. Augmenting the data with simulated growth rates of non-infected half-sibs (ADG(0)) helped resolve this statistical confounding and indicated that genetic variation in tolerance to PRRS may exist if genetic correlations between ADG(0) and ADG(21) or ADG(42) are low to moderate. CONCLUSIONS: Evidence for genetic variation in tolerance of pigs to PRRS was weak when based on data from infected piglets only. However, simulations indicated that genetic variance in tolerance may exist and could be detected if comparable data on uninfected relatives were available. In conclusion, of the two defense strategies, genetics of tolerance is more difficult to elucidate than genetics of resistance. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12711-017-0312-7) contains supplementary material, which is available to authorized users. BioMed Central 2017-04-19 /pmc/articles/PMC5396128/ /pubmed/28424056 http://dx.doi.org/10.1186/s12711-017-0312-7 Text en © The Author(s) 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Lough, Graham
Rashidi, Hamed
Kyriazakis, Ilias
Dekkers, Jack C. M.
Hess, Andrew
Hess, Melanie
Deeb, Nader
Kause, Antti
Lunney, Joan K.
Rowland, Raymond R. R.
Mulder, Han A.
Doeschl-Wilson, Andrea
Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
title Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
title_full Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
title_fullStr Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
title_full_unstemmed Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
title_short Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
title_sort use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5396128/
https://www.ncbi.nlm.nih.gov/pubmed/28424056
http://dx.doi.org/10.1186/s12711-017-0312-7
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