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Fracasso G, Heylen D, Van Dongen S, Elst J, Matthysen E. Predictors of individual performance and evolutionary potential of life-history traits in a hematophagous ectoparasite. Evolution 2022; 76:799-816. [PMID: 35238032 PMCID: PMC9314103 DOI: 10.1111/evo.14463] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/12/2021] [Accepted: 01/07/2022] [Indexed: 01/22/2023]
Abstract
Little is known about the intraspecific variation of parasite life-history traits and how this variation may affect parasite fitness and evolution. We investigated how life-history traits predict success of individual tree-hole ticks Ixodes arboricola and estimated their evolutionary potential, as well as genetic correlations within stages and phenotypic correlations within and across stages. Ticks were followed individually over two generations while allowed to feed on great tits Parus major. After accounting for host and tick maternal effects, we found that short feeding times and high engorgement weights strongly increased molting success. Molting time was also positively correlated with feeding success in adults. In larvae and nymphs, we found negative phenotypic correlations between engorgement weight and both feeding and molting time, the latter supported by a negative genetic correlation. We found sex-related differences in feeding time (longer in male nymphs) and molting time (longer in male larvae but shorter in male nymphs). Also, time since the last feeding event (set experimentally) reduced larval and nymphal fitness, whereas it increased adult female fitness. Furthermore, we found significant heritability and evolvability, that is, the potential to respond to selection, for engorgement weight and molting time across all stages but no significant heritability for feeding time. Our findings suggest that variation in tick fitness is shaped by consistent individual differences in tick quality, for which engorgement weight is a good proxy, rather than by life-history trade-offs.
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Affiliation(s)
- Gerardo Fracasso
- Evolutionary Ecology Group, Department of BiologyUniversity of AntwerpWilrijkB‐2610Belgium
| | - Dieter Heylen
- Interuniversity Institute for Biostatistics and statistical BioinformaticsHasselt UniversityDiepenbeekB‐3590Belgium
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew Jersey08544
- Eco‐Epidemiology Group, Department of Biomedical SciencesInstitute of Tropical MedicineAntwerpB‐2000Belgium
| | - Stefan Van Dongen
- Evolutionary Ecology Group, Department of BiologyUniversity of AntwerpWilrijkB‐2610Belgium
| | - Joris Elst
- Evolutionary Ecology Group, Department of BiologyUniversity of AntwerpWilrijkB‐2610Belgium
| | - Erik Matthysen
- Evolutionary Ecology Group, Department of BiologyUniversity of AntwerpWilrijkB‐2610Belgium
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de Araujo Neto FR, dos Santos JCG, da Silva Arce CD, Borquis RRA, dos Santos DJA, Guimarães KC, do Nascimento AV, de Oliveira HN, Tonhati H. Genomic study of the resilience of buffalo cows to a negative energy balance. J Appl Genet 2022; 63:379-388. [DOI: 10.1007/s13353-021-00680-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 11/15/2021] [Accepted: 12/23/2021] [Indexed: 11/27/2022]
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Knap PW, Doeschl-Wilson A. Why breed disease-resilient livestock, and how? Genet Sel Evol 2020; 52:60. [PMID: 33054713 PMCID: PMC7557066 DOI: 10.1186/s12711-020-00580-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 10/01/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Fighting and controlling epidemic and endemic diseases represents a considerable cost to livestock production. Much research is dedicated to breeding disease resilient livestock, but this is not yet a common objective in practical breeding programs. In this paper, we investigate how future breeding programs may benefit from recent research on disease resilience. MAIN BODY We define disease resilience in terms of its component traits resistance (R: the ability of a host animal to limit within-host pathogen load (PL)) and tolerance (T: the ability of an infected host to limit the damage caused by a given PL), and model the host's production performance as a reaction norm on PL, depending on R and T. Based on this, we derive equations for the economic values of resilience and its component traits. A case study on porcine respiratory and reproductive syndrome (PRRS) in pigs illustrates that the economic value of increasing production in infectious conditions through selection for R and T can be more than three times higher than by selection for production in disease-free conditions. Although this reaction norm model of resilience is helpful for quantifying its relationship to its component traits, its parameters are difficult and expensive to quantify. We consider the consequences of ignoring R and T in breeding programs that measure resilience as production in infectious conditions with unknown PL-particularly, the risk that the genetic correlation between R and T is unfavourable (antagonistic) and that a trade-off between them neutralizes the resilience improvement. We describe four approaches to avoid such antagonisms: (1) by producing sufficient PL records to estimate this correlation and check for antagonisms-if found, continue routine PL recording, and if not found, shift to cheaper proxies for PL; (2) by selection on quantitative trait loci (QTL) known to influence both R and T in favourable ways; (3) by rapidly modifying towards near-complete resistance or tolerance, (4) by re-defining resilience as the animal's capacity to resist (or recover from) the perturbation caused by an infection, measured as temporal deviations of production traits in within-host longitudinal data series. CONCLUSIONS All four alternatives offer promising options for genetic improvement of disease resilience, and most rely on technological and methodological developments and innovation in automated data generation.
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Affiliation(s)
| | - Andrea Doeschl-Wilson
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush Estate, Edinburgh, EH25 9RG Scotland, UK
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4
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Ferris C, Best A. The effect of temporal fluctuations on the evolution of host tolerance to parasitism. Theor Popul Biol 2019; 130:182-190. [PMID: 31415775 DOI: 10.1016/j.tpb.2019.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/29/2019] [Accepted: 07/29/2019] [Indexed: 11/19/2022]
Abstract
There are many mechanisms that hosts can evolve to defend against parasites, two of which are resistance and tolerance. These defences often have different evolutionary behaviours, and it is important to consider how each individual mechanism may respond to changes in environment. In particular, host defence through tolerance is predicted to be unlikely to lead to variation, despite many observations of diversity in both animal and plant systems. Hence understanding the drivers of diversity in host defence and parasite virulence is vital for predicting future evolutionary changes in infectious disease dynamics. It has been suggested that heterogeneous environments might generally promote diversity, but the effect of temporal fluctuations has received little attention theoretically or empirically, and there has been no examination of how temporal fluctuations affects the evolution of host tolerance. In this study, we use a mathematical model to investigate the evolution of host tolerance in a temporally fluctuating environment. We show that investment in tolerance increases in more variable environments, giving qualitatively different evolutionary behaviours when compared to resistance. Once seasonality is introduced evolutionary branching though tolerance can occur and create diversity within the population, although potentially only temporarily. This branching behaviour arises due to the emergence of a negative feedback with the maximum infected density on a cycle, which is strongest when the infected population is large. This work reinforces the qualitative differences between tolerance and resistance evolution, but also provides theoretical evidence for the theory that heterogeneous environments promote host-parasite diversity, hence constant environment assumptions may omit important evolutionary outcomes.
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Affiliation(s)
- Charlotte Ferris
- School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK.
| | - Alex Best
- School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK
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5
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Anacleto O, Cabaleiro S, Villanueva B, Saura M, Houston RD, Woolliams JA, Doeschl-Wilson AB. Genetic differences in host infectivity affect disease spread and survival in epidemics. Sci Rep 2019; 9:4924. [PMID: 30894567 PMCID: PMC6426847 DOI: 10.1038/s41598-019-40567-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 02/12/2019] [Indexed: 12/17/2022] Open
Abstract
Survival during an epidemic is partly determined by host genetics. While quantitative genetic studies typically consider survival as an indicator for disease resistance (an individual's propensity to avoid becoming infected or diseased), mortality rates of populations undergoing an epidemic are also affected by endurance (the propensity of diseased individual to survive the infection) and infectivity (i.e. the propensity of an infected individual to transmit disease). Few studies have demonstrated genetic variation in disease endurance, and no study has demonstrated genetic variation in host infectivity, despite strong evidence for considerable phenotypic variation in this trait. Here we propose an experimental design and statistical models for estimating genetic diversity in all three host traits. Using an infection model in fish we provide, for the first time, direct evidence for genetic variation in host infectivity, in addition to variation in resistance and endurance. We also demonstrate how genetic differences in these three traits contribute to survival. Our results imply that animals can evolve different disease response types affecting epidemic survival rates, with important implications for understanding and controlling epidemics.
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Affiliation(s)
- Osvaldo Anacleto
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
- Institute of Mathematical and Computer Sciences, University of São Paulo, São Carlos, Brazil.
| | - Santiago Cabaleiro
- Centro Tecnológico del Cluster de la Acuicultura (CETGA), A Coruña, Spain
| | | | - María Saura
- Departamento de Mejora Genética Animal, INIA, Madrid, Spain
| | - Ross D Houston
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - John A Woolliams
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - Andrea B Doeschl-Wilson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
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Nakov D, Hristov S, Stankovic B, Pol F, Dimitrov I, Ilieski V, Mormede P, Hervé J, Terenina E, Lieubeau B, Papanastasiou DK, Bartzanas T, Norton T, Piette D, Tullo E, van Dixhoorn IDE. Methodologies for Assessing Disease Tolerance in Pigs. Front Vet Sci 2019; 5:329. [PMID: 30687721 PMCID: PMC6334556 DOI: 10.3389/fvets.2018.00329] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022] Open
Abstract
Features of intensive farming can seriously threaten pig homeostasis, well-being and productivity. Disease tolerance of an organism is the adaptive ability in preserving homeostasis and at the same time limiting the detrimental impact that infection can inflict on its health and performance without affecting pathogen burden per se. While disease resistance (DRs) can be assessed measuring appropriately the pathogen burden within the host, the tolerance cannot be quantified easily. Indeed, it requires the assessment of the changes in performance as well as the changes in pathogen burden. In this paper, special attention is given to criteria required to standardize methodologies for assessing disease tolerance (DT) in respect of infectious diseases in pigs. The concept is applied to different areas of expertise and specific examples are given. The basic physiological mechanisms of DT are reviewed. Disease tolerance pathways, genetics of the tolerance-related traits, stress and disease tolerance, and role of metabolic stress in DT are described. In addition, methodologies based on monitoring of growth and reproductive performance, welfare, emotional affective states, sickness behavior for assessment of disease tolerance, and methodologies based on the relationship between environmental challenges and disease tolerance are considered. Automated Precision Livestock Farming technologies available for monitoring performance, health and welfare-related measures in pig farms, and their limitations regarding DT in pigs are also presented. Since defining standardized methodologies for assessing DT is a serious challenge for biologists, animal scientists and veterinarians, this work should contribute to improvement of health, welfare and production in pigs.
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Affiliation(s)
- Dimitar Nakov
- Faculty of Agricultural Sciences and Food, University Ss. Cyril and Methodius in Skopje, Skopje, Macedonia
| | - Slavcha Hristov
- Faculty of Agriculture, University of Belgrade, Belgrade, Serbia
| | | | - Françoise Pol
- Agence Nationale de Sécurité Sanitaire (ANSES), Université Bretagne-Loire, Ploufragan, France
| | - Ivan Dimitrov
- Department of Animal Breeding, Agricultural Institute, Stara Zagora, Bulgaria
| | - Vlatko Ilieski
- Faculty of Veterinary Medicine, University Ss. Cyril and Methodius in Skopje, Skopje, Macedonia
| | - Pierre Mormede
- GenPhySE, Université de Toulouse, INRA, ENVT, Castanet Tolosan, France
| | - Julie Hervé
- IECM, INRA, Oniris, Université Bretagne Loire, Nantes, France
| | - Elena Terenina
- GenPhySE, Université de Toulouse, INRA, ENVT, Castanet Tolosan, France
| | | | - Dimitrios K Papanastasiou
- Centre for Research and Technology Hellas, Institute of Bio-Economy and Agri-Technology, Volos, Greece
| | - Thomas Bartzanas
- Centre for Research and Technology Hellas, Institute of Bio-Economy and Agri-Technology, Volos, Greece
| | | | | | - Emanuela Tullo
- Department of Environmental Science and Policy, Milan, Italy
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Boulton K, Nolan MJ, Wu Z, Psifidi A, Riggio V, Harman K, Bishop SC, Kaiser P, Abrahamsen MS, Hawken R, Watson KA, Tomley FM, Blake DP, Hume DA. Phenotypic and genetic variation in the response of chickens to Eimeria tenella induced coccidiosis. Genet Sel Evol 2018; 50:63. [PMID: 30463512 PMCID: PMC6249784 DOI: 10.1186/s12711-018-0433-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 11/14/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Coccidiosis is a major contributor to losses in poultry production. With emerging constraints on the use of in-feed prophylactic anticoccidial drugs and the relatively high costs of effective vaccines, there are commercial incentives to breed chickens with greater resistance to this important production disease. To identify phenotypic biomarkers that are associated with the production impacts of coccidiosis, and to assess their covariance and heritability, 942 Cobb500 commercial broilers were subjected to a defined challenge with Eimeria tenella (Houghton). Three traits were measured: weight gain (WG) during the period of infection, caecal lesion score (CLS) post mortem, and the level of a serum biomarker of intestinal inflammation, i.e. circulating interleukin 10 (IL-10), measured at the height of the infection. RESULTS Phenotypic analysis of the challenged chicken cohort revealed a significant positive correlation between CLS and IL-10, with significant negative correlations of both these traits with WG. Eigenanalysis of phenotypic covariances between measured traits revealed three distinct eigenvectors. Trait weightings of the first eigenvector, (EV1, eigenvalue = 59%), were biologically interpreted as representing a response of birds that were susceptible to infection, with low WG, high CLS and high IL-10. Similarly, the second eigenvector represented infection resilience/resistance (EV2, 22%; high WG, low CLS and high IL-10), and the third eigenvector tolerance (EV3, 19%; high WG, high CLS and low IL-10), respectively. Genome-wide association studies (GWAS) identified two SNPs that were associated with WG at the suggestive level. CONCLUSIONS Eigenanalysis separated the phenotypic impact of a defined challenge with E. tenella on WG, caecal inflammation/pathology, and production of IL-10 into three major eigenvectors, indicating that the susceptibility-resistance axis is not a single continuous quantitative trait. The SNPs identified by the GWAS for body weight were located in close proximity to two genes that are involved in innate immunity (FAM96B and RRAD).
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Affiliation(s)
- Kay Boulton
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Matthew J. Nolan
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, UK
| | - Zhiguang Wu
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Androniki Psifidi
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
- Department of Clinical Sciences and Services, Royal Veterinary College, University of London, Hatfield, UK
| | - Valentina Riggio
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Kimberley Harman
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, UK
| | - Stephen C. Bishop
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Pete Kaiser
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | | | - Rachel Hawken
- Cobb-Vantress Inc., PO Box 1030, Siloam Springs, AR USA
| | - Kellie A. Watson
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Fiona M. Tomley
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, UK
| | - Damer P. Blake
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, UK
| | - David A. Hume
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
- Mater Research Institute, University of Queensland, Brisbane, St. Lucia, QLD, Brisbane, Australia
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8
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Chu TT, Alemu SW, Norberg E, Sørensen AC, Henshall J, Hawken R, Jensen J. Benefits of testing in both bio-secure and production environments in genomic selection breeding programs for commercial broiler chicken. Genet Sel Evol 2018; 50:52. [PMID: 30390619 PMCID: PMC6215651 DOI: 10.1186/s12711-018-0430-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 10/25/2018] [Indexed: 12/05/2022] Open
Abstract
Background A breeding program for commercial broiler chicken that is carried out under strict biosecure conditions can show reduced genetic gain due to genotype by environment interactions (G × E) between bio-secure (B) and commercial production (C) environments. Accuracy of phenotype-based best linear unbiased prediction of breeding values of selection candidates using sib-testing in C is low. Genomic prediction based on dense genetic markers may improve accuracy of selection. Stochastic simulation was used to explore the benefits of genomic selection in breeding schemes for broiler chicken that include birds in both B and C for assessment of phenotype. Results When genetic correlations (\documentclass[12pt]{minimal}
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\begin{document}$$r_{g}$$\end{document}rg) between traits measured in B and C were equal to 0.5 and 0.7, breeding schemes with 15, 30 and 45% of birds assessed in C resulted in higher genetic gain for performance in C compared to those without birds in C. The optimal proportion of birds phenotyped in C for genetic gain was 30%. When the proportion of birds in C was optimal and genotyping effort was limited, allocating 30% of the genotyping effort to birds in C was also the optimal genotyping strategy for genetic gain. When \documentclass[12pt]{minimal}
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\begin{document}$$r_{g}$$\end{document}rg was equal to 0.9, genetic gain for performance in C was not improved with birds in C compared to schemes without birds in C. Increasing the heritability of traits assessed in C increased genetic gain significantly. Rates of inbreeding decreased when the proportion of birds in C increased because of a lower selection intensity among birds retained in B and a reduction in the probability of co-selecting close relatives. Conclusions If G × E interactions (\documentclass[12pt]{minimal}
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\begin{document}$$r_{g}$$\end{document}rg of 0.5 and 0.7) are strong, a genomic selection scheme in which 30% of the birds hatched are phenotyped in C has larger genetic gain for performance in C compared to phenotyping all birds in B. Rates of inbreeding decreased as the proportion of birds moved to C increased from 15 to 45%.
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Affiliation(s)
- Thinh T Chu
- Department of Molecular Biology and Genetics, Center for Quantitative Genetics and Genomics, Aarhus University, 8830, Tjele, Denmark. .,Wageningen University and Research Animal Breeding and Genomics, 6709 PG, Wageningen, The Netherlands.
| | - Setegn W Alemu
- Department of Molecular Biology and Genetics, Center for Quantitative Genetics and Genomics, Aarhus University, 8830, Tjele, Denmark
| | - Elise Norberg
- Department of Molecular Biology and Genetics, Center for Quantitative Genetics and Genomics, Aarhus University, 8830, Tjele, Denmark.,Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, 1432, Ås, Norway
| | - Anders C Sørensen
- Department of Molecular Biology and Genetics, Center for Quantitative Genetics and Genomics, Aarhus University, 8830, Tjele, Denmark
| | - John Henshall
- Cobb-Vantress Inc., Siloam Springs, AR, 72761-1030, USA
| | - Rachel Hawken
- Cobb-Vantress Inc., Siloam Springs, AR, 72761-1030, USA
| | - Just Jensen
- Department of Molecular Biology and Genetics, Center for Quantitative Genetics and Genomics, Aarhus University, 8830, Tjele, Denmark
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da Costa Caetano G, Fonseca Silva F, Calderano A, Pinheiro Silva L, Corrêa Ribeiro J, Tavares Oliveira L, Reis Mota R. Genotype and protein level interaction in growth traits of meat-type quail through reaction norm models. JOURNAL OF ANIMAL AND FEED SCIENCES 2017. [DOI: 10.22358/jafs/79806/2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lough G, Rashidi H, Kyriazakis I, Dekkers JCM, Hess A, Hess M, Deeb N, Kause A, Lunney JK, Rowland RRR, Mulder HA, Doeschl-Wilson A. Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus. Genet Sel Evol 2017; 49:37. [PMID: 28424056 PMCID: PMC5396128 DOI: 10.1186/s12711-017-0312-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/29/2017] [Indexed: 12/31/2022] Open
Abstract
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 (VL21) or 0 to 42 (VL42) days post-infection and tolerance as the slope of the reaction-norm of average daily gain (ADG21, ADG42) on VL21 or VL42. 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 ADG21 and ADG42 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 (ADG0) helped resolve this statistical confounding and indicated that genetic variation in tolerance to PRRS may exist if genetic correlations between ADG0 and ADG21 or ADG42 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.
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Affiliation(s)
- Graham Lough
- The Roslin Institute & R(D)SVS, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Hamed Rashidi
- Animal Breeding and Genomics Centre, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, The Netherlands
| | - Ilias Kyriazakis
- School of Agriculture Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | | | - Andrew Hess
- Department of Animal Science, Iowa State University, Ames, IA 50011 USA
| | - Melanie Hess
- Department of Animal Science, Iowa State University, Ames, IA 50011 USA
| | - Nader Deeb
- Genus plc, 100 Bluegrass Commons Blvd. Suite 2200, Hendersonville, TN 37075 USA
| | - Antti Kause
- Biometrical Genetics, Natural Resources Institute Finland, 00790 Jokioinen, Finland
| | - Joan K. Lunney
- Animal Parasitic Diseases Laboratory, USDA, Beltsville, MD 20705 USA
| | | | - Han A. Mulder
- Animal Breeding and Genomics Centre, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, The Netherlands
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Habtewold T, Groom Z, Christophides GK. Immune resistance and tolerance strategies in malaria vector and non-vector mosquitoes. Parasit Vectors 2017; 10:186. [PMID: 28420446 PMCID: PMC5395841 DOI: 10.1186/s13071-017-2109-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 03/24/2017] [Indexed: 11/10/2022] Open
Abstract
Background The Anopheles gambiae complex consists of species that vary greatly in their capacity to transmit malaria. The mosquito immune system has been identified as a key factor that can influence whether Plasmodium infection establishes within the mosquito vector. This study was designed to investigate the immune responses of An. coluzzii, An. arabiensis and An. quadriannulatus mosquitoes. The first two mosquito species are major vectors of malaria in sub-Saharan Africa, while the third is thought to be a non-vector. Methods All three mosquito species were reared in mixed cultures. Their capacity to eliminate P. berghei and regulate midgut bacteria was examined. Results Our results revealed large differences in mosquito resistance to P. berghei. In all three mosquito species, immune reactions involving the complement system were triggered when the number of parasites that mosquitoes were challenged with exceeded a certain level, i.e. immune tolerance threshold. This threshold was markedly lower in An. quadriannulatus compared to An. coluzzii and An. arabiensis. We also demonstrated that the level of immune tolerance to P. berghei infection in the haemolymph is inversely correlated with the level of immune tolerance to microbiota observed in the midgut lumen after a blood meal. The malaria non-vector mosquito species, An. quadriannulatus was shown to have a much higher level of tolerance to microbiota in the midgut than An. coluzzii. Conclusions We propose a model whereby an increased tolerance to microbiota in the mosquito midgut results in lower tolerance to Plasmodium infection. In this model, malaria non-vector mosquito species are expected to have increased immune resistance in the haemocoel, possibly due to complement priming by microbiota elicitors. We propose that this strategy is employed by the malaria non-vector mosquito, An. quadriannulatus, while An. coluzzii has reduced tolerance to bacterial infection in the midgut and consequently reduced immune resistance to Plasmodium infection at the haemocoel level. An in-depth understanding of the molecular mechanisms regulating immune tolerance versus resistance in different mosquito vectors of malaria could guide the design of new vector and disease control strategies. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2109-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tibebu Habtewold
- Department of Life Sciences, Imperial College London, London, UK. .,Department of Comparative Physiology and Biometrics, University of Ghent, Ghent, Belgium.
| | - Zoe Groom
- Department of Life Sciences, Imperial College London, London, UK.,Costello Medical Consulting, Cambridge, UK
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Herrero-Medrano JM, Mathur PK, ten Napel J, Rashidi H, Alexandri P, Knol EF, Mulder HA. Estimation of genetic parameters and breeding values across challenged environments to select for robust pigs. J Anim Sci 2016; 93:1494-502. [PMID: 26020171 DOI: 10.2527/jas.2014-8583] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Robustness is an important issue in the pig production industry. Since pigs from international breeding organizations have to withstand a variety of environmental challenges, selection of pigs with the inherent ability to sustain their productivity in diverse environments may be an economically feasible approach in the livestock industry. The objective of this study was to estimate genetic parameters and breeding values across different levels of environmental challenge load. The challenge load (CL) was estimated as the reduction in reproductive performance during different weeks of a year using 925,711 farrowing records from farms distributed worldwide. A wide range of levels of challenge, from favorable to unfavorable environments, was observed among farms with high CL values being associated with confirmed situations of unfavorable environment. Genetic parameters and breeding values were estimated in high- and low-challenge environments using a bivariate analysis, as well as across increasing levels of challenge with a random regression model using Legendre polynomials. Although heritability estimates of number of pigs born alive were slightly higher in environments with extreme CL than in those with intermediate levels of CL, the heritabilities of number of piglet losses increased progressively as CL increased. Genetic correlations among environments with different levels of CL suggest that selection in environments with extremes of low or high CL would result in low response to selection. Therefore, selection programs of breeding organizations that are commonly conducted under favorable environments could have low response to selection in commercial farms that have unfavorable environmental conditions. Sows that had experienced high levels of challenge at least once during their productive life were ranked according to their EBV. The selection of pigs using EBV ignoring environmental challenges or on the basis of records from only favorable environments resulted in a sharp decline in productivity as the level of challenge increased. In contrast, selection using the random regression approach resulted in limited change in productivity with increasing levels of challenge. Hence, we demonstrate that the use of a quantitative measure of environmental CL and a random regression approach can be comprehensively combined for genetic selection of pigs with enhanced ability to maintain high productivity in harsh environments.
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Begli HE, Torshizi RV, Masoudi AA, Ehsani A, Jensen J. Longitudinal analysis of body weight, feed intake and residual feed intake in F2 chickens. Livest Sci 2016. [DOI: 10.1016/j.livsci.2015.11.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hayward AD, Nussey DH, Wilson AJ, Berenos C, Pilkington JG, Watt KA, Pemberton JM, Graham AL. Natural selection on individual variation in tolerance of gastrointestinal nematode infection. PLoS Biol 2014; 12:e1001917. [PMID: 25072883 PMCID: PMC4114752 DOI: 10.1371/journal.pbio.1001917] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 06/19/2014] [Indexed: 11/19/2022] Open
Abstract
A 25-year study of wild sheep shows that individuals vary in how quickly they lose weight as parasite infections increase, and that those who lose the least weight when heavily infected produce more offspring. Hosts may mitigate the impact of parasites by two broad strategies: resistance, which limits parasite burden, and tolerance, which limits the fitness or health cost of increasing parasite burden. The degree and causes of variation in both resistance and tolerance are expected to influence host–parasite evolutionary and epidemiological dynamics and inform disease management, yet very little empirical work has addressed tolerance in wild vertebrates. Here, we applied random regression models to longitudinal data from an unmanaged population of Soay sheep to estimate individual tolerance, defined as the rate of decline in body weight with increasing burden of highly prevalent gastrointestinal nematode parasites. On average, individuals lost weight as parasite burden increased, but whereas some lost weight slowly as burden increased (exhibiting high tolerance), other individuals lost weight significantly more rapidly (exhibiting low tolerance). We then investigated associations between tolerance and fitness using selection gradients that accounted for selection on correlated traits, including body weight. We found evidence for positive phenotypic selection on tolerance: on average, individuals who lost weight more slowly with increasing parasite burden had higher lifetime breeding success. This variation did not have an additive genetic basis. These results reveal that selection on tolerance operates under natural conditions. They also support theoretical predictions for the erosion of additive genetic variance of traits under strong directional selection and fixation of genes conferring tolerance. Our findings provide the first evidence of selection on individual tolerance of infection in animals and suggest practical applications in animal and human disease management in the face of highly prevalent parasites. Animals can defend themselves against parasites through either resistance (reducing parasite numbers, for example, by killing them) or tolerance (maintaining health as infections levels increase, for example, by repairing damage). Resistance has been well-studied in wild animals, but tolerance has been less so. We analysed data on body weight collected over 25 years on a natural population of Soay sheep, infected with parasitic gut worms. As parasite burden increased, sheep lost weight. Crucially, there was variation among individuals: some lost weight rapidly with increasing infections (i.e., showed “low tolerance”), whereas others lost weight slowly (i.e., showed “high tolerance”). The least tolerant individuals lost 4.5 kg of body weight across the range of parasite burdens that we saw, whereas the most tolerant lost only around 0.36 kg. However, variation in tolerance did not have a heritable genetic basis, so that although tolerance varied between individuals, this was not due to genetic differences. Further analysis revealed that there was natural selection on tolerance. Individuals who were more tolerant of infection produced more offspring over the course of their lives. This study shows that natural selection can act upon resistance and tolerance simultaneously in nature, a result that has implications for both human health and livestock management.
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Affiliation(s)
- Adam D. Hayward
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
- * E-mail: (ADH); (ALG)
| | - Daniel H. Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Alastair J. Wilson
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, Cornwall, United Kingdom
| | - Camillo Berenos
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jill G. Pilkington
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Kathryn A. Watt
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrea L. Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (ADH); (ALG)
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Mazé-Guilmo E, Loot G, Páez DJ, Lefèvre T, Blanchet S. Heritable variation in host tolerance and resistance inferred from a wild host-parasite system. Proc Biol Sci 2014; 281:20132567. [PMID: 24478295 DOI: 10.1098/rspb.2013.2567] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hosts have evolved two distinct defence strategies against parasites: resistance (which prevents infection or limit parasite growth) and tolerance (which alleviates the fitness consequences of infection). However, heritable variation in resistance and tolerance and the genetic correlation between these two traits have rarely been characterized in wild host populations. Here, we estimate these parameters for both traits in Leuciscus burdigalensis, a freshwater fish parasitized by Tracheliastes polycolpus. We used a genetic database to construct a full-sib pedigree in a wild L. burdigalensis population. We then used univariate animal models to estimate inclusive heritability (i.e. all forms of genetic and non-genetic inheritance) in resistance and tolerance. Finally, we assessed the genetic correlation between these two traits using a bivariate animal model. We found significant heritability for resistance (H = 17.6%; 95% CI: 7.2-32.2%) and tolerance (H = 18.8%; 95% CI: 4.4-36.1%), whereas we found no evidence for the existence of a genetic correlation between these traits. Furthermore, we confirm that resistance and tolerance are strongly affected by environmental effects. Our results demonstrate that (i) heritable variation exists for parasite resistance and tolerance in wild host populations, and (ii) these traits can evolve independently in populations.
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Affiliation(s)
- Elise Mazé-Guilmo
- Centre National de la Recherche Scientifique (CNRS), Station d'Ecologie Expérimentale du CNRS à Moulis, , USR 2936, 09200 Moulis, France, Université de Toulouse, , UPS, UMR5174 EDB (Laboratoire Évolution and Diversité Biologique), 118 route de Narbonne, 31062 Toulouse Cedex, France, Department of Ecology and Evolution, University of Chicago, , 1101 E 57th Street, Erman 103, Chicago, IL 60637, USA, Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC) UMR (IRD/CNRS/UM) 5290, , Centre IRD-911 Avenue Agropolis, BP 64501 Montpellier, France, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, École Nationale de Formation Agronomique (ENFA), UMR5174 EDB (Laboratoire Évolution and Diversité Biologique), , 118 route de Narbonne, 31062 Toulouse Cedex 4, France
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Rashidi H, Mulder HA, Mathur P, van Arendonk JAM, Knol EF. Variation among sows in response to porcine reproductive and respiratory syndrome1. J Anim Sci 2014; 92:95-105. [DOI: 10.2527/jas.2013-6889] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- H. Rashidi
- Animal Breeding and Genomics Centre, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, the Netherlands
| | - H. A. Mulder
- Animal Breeding and Genomics Centre, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, the Netherlands
| | - P. Mathur
- TOPIGS Research Center IPG, P.O. Box 43, 6640 AA Beuningen, the Netherlands
| | - J. A. M. van Arendonk
- Animal Breeding and Genomics Centre, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, the Netherlands
| | - E. F. Knol
- TOPIGS Research Center IPG, P.O. Box 43, 6640 AA Beuningen, the Netherlands
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Kause A, Odegård J. The genetic analysis of tolerance to infections: a review. Front Genet 2012; 3:262. [PMID: 23403850 PMCID: PMC3565848 DOI: 10.3389/fgene.2012.00262] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 11/05/2012] [Indexed: 11/23/2022] Open
Abstract
Tolerance to infections is defined as the ability of a host to limit the impact of a given pathogen burden on host performance. Uncoupling resistance and tolerance is a challenge, and there is a need to be able to separate them using specific trait recording or statistical methods. We present three statistical methods that can be used to investigate genetics of tolerance-related traits. Firstly, using random regressions, tolerance can be analyzed as a reaction norm slope in which host performance (y-axis) is regressed against an increasing pathogen burden (x-axis). Genetic variance in tolerance slopes is the genetic variance for tolerance. Variation in tolerance can induce genotype re-ranking and changes in genetic and phenotypic variation in host performance along the pathogen burden trajectory, contributing to environment-dependent genetic responses to selection. Such genotype-by-environment interactions can be quantified by combining random regressions and covariance functions. To apply random regressions, pathogen burden of individuals needs to be recorded. Secondly, when pathogen burden is not recorded, the cure model for time-until-death data allows separating two traits, susceptibility and endurance. Susceptibility is whether or not an individual was susceptible to an infection, whereas endurance denotes how long time it took until the infection killed a susceptible animal (influenced by tolerance). Thirdly, the normal mixture model can be used to classify continuously distributed host performance, such as growth rate, into different sub-classes (e.g., non-infected and infected), which allows estimation of host performance reduction specific to infected individuals. Moreover, genetics of host performance can be analyzed separately in healthy and affected animals, even in the absence of pathogen burden and survival data. These methods provide novel tools to increase our understanding on the impact of parasites, pathogens, and production diseases on host traits.
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Affiliation(s)
- Antti Kause
- Biotechnology and Food Research, Biometrical Genetics, MTT Agrifood Research Finland Jokioinen, Finland
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