Deciphering the genetic control of innate and adaptive immune responses in pig: a combined genetic and genomic study

Improving animal robustness and resistance to pathogens by adding health criteria in selection schemes is one of the challenging objectives of the next decade. In order to better understand the genetic control of immunity in French Large White pigs, we have launched a program combining genetic and genomic studies not focussing on any particular pathogen. Animals recorded for production traits were scored for a wide range of immunity parameters three weeks after vaccination against Mycoplasma hyopneumoniae: i) total white blood cells and lymphocyte counts and proportions of various leucocyte subsets including cells harbouring IgM, γδTCR, CD4/CD8, CD16/CD2 and CD16/CD172a/MHCII, ii) innate immune response parameters (phagocytosis and in vitro production of IL1B, IL6, IL8, TNF, IL12 and IFNαafter blood stimulation), iii) adaptive immune response parameters (lymphocyte proliferation, in vitro production of IL2, IL4, IL10 and IFNγ after blood stimulation, total IgG, IgA, IgM and specific IgG levels) and iv) two acute phase proteins (C-reactive protein and haploglobin). Across traits, heritability estimates reached 0.4 on average (se=0.1) and 42 of the 54 measured parameters showed moderate to high heritabilities (≥0.2), confirming that many parameters are under genetic control and could be included in selection protocols. Functional analyses revealed that the blood transcriptome is informative for part of the immunity traits and should provide relevant phenotypic information to better characterize some immunity traits

Immunity Traits in Pigs: Substantial Genetic Variation and Limited Covariation

BACKGROUND: Increasing robustness via improvement of resistance to pathogens is a major selection objective in livestock breeding. As resistance traits are difficult or impossible to measure directly, potential indirect criteria are measures of immune traits (ITs). Our underlying hypothesis is that levels of ITs with no focus on specific pathogens define an individual's immunocompetence and thus predict response to pathogens in general. Since variation in ITs depends on genetic, environmental and probably epigenetic factors, our aim was to estimate the relative importance of genetics. In this report, we present a large genetic survey of innate and adaptive ITs in pig families bred in the same environment. METHODOLOGY/PRINCIPAL FINDINGS: Fifty four ITs were studied on 443 Large White pigs vaccinated against Mycoplasma hyopneumoniae and analyzed by combining a principal component analysis (PCA) and genetic parameter estimation. ITs include specific and non specific antibodies, seric inflammatory proteins, cell subsets by hemogram and flow cytometry, ex vivo production of cytokines (IFNα, TNFα, IL6, IL8, IL12, IFNγ, IL2, IL4, IL10), phagocytosis and lymphocyte proliferation. While six ITs had heritabilities that were weak or not significantly different from zero, 18 and 30 ITs had moderate (0.1<h2≤0.4) or high (h2>0.4) heritability values, respectively. Phenotypic and genetic correlations between ITs were weak except for a few traits that mostly include cell subsets. PCA revealed no cluster of innate or adaptive ITs. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that variation in many innate and adaptive ITs is genetically controlled in swine, as already reported for a smaller number of traits by other laboratories. A limited redundancy of the traits was also observed confirming the high degree of complementarity between innate and adaptive ITs. Our data provide a genetic framework for choosing ITs to be included as selection criteria in multitrait selection programmes that aim to improve both production and health traits

Effet du génotype halothane sur les performances d'engraissement, de carcasse et de qualité de la viande du porc charcutier

National audienc

Estimation of genetic trends from 1977 to 2000 for stress-responsive systems in French Large White and Landrace pig populations using frozen semen

Chantier qualité GAAn experimental design aiming at analysing the consequences of genetic selection from 1977 to 1998–2000 on the evolution of stress-responsive systems in the French Large White (LW) and Landrace (LR) pig populations was conducted by INRA and IFIP-Institut du Porc. Large White sows were inseminated with semen from LW boars born in 1977 (frozen semen) or in 1998 and their second-generation offspring were station-tested. Landrace sows were inseminated with semen from LR boars born in 1977 (frozen semen) or in 1999 to 2000, and their progeny was station-tested. Urinary concentration of stress hormones (cortisol and catecholamines) and traits related to carcass composition (estimated carcass lean content (ECLC) and global adiposity) and meat quality (pH 24 h) were measured. For the two populations, selection carried out since 1977 led to an increase in ECLC and a decrease in carcass adiposity. Between 1977 and 1998 to 2000, urinary concentrations of stress hormones were unchanged in the LR breed, but were decreased in the LW breed. Moreover, for the animals generated from LW boars born in 1977 and in 1998, urinary cortisol levels were negatively correlated with ECLC. Therefore, in the LW breed, selection carried out for higher ECLC resulted in a decrease in cortisol production, as well as a reduction of catecholamine production that may be responsible for the lower ultimate pH of meat. Therefore, selection carried out for increased carcass lean content led, in this breed, to large modifications in the functioning of the stress-responsive systems, thereby influencing a large range of physiological regulations and technical properties such as carcass composition and meat pH, which remained however in the normal range for acceptable meat quality

Etude de quelques facteurs de variation du défaut viande déstructurée sur le jambon frais.

International audienc

Décryptage du contrôle génétique des réponses immunitaires innées et adaptatives chez le porc Large White : une étude combinant des approches génétiques et fonctionnelles

Une étude combinant des approches génétiques et fonctionnelles. Un programme d'analyse fine du contrôle génétique de la réponse immunitaire (RI) combinant des approches génétiques et fonctionnelles a été développé. Plus de 400 animaux de race Large White mesurés pour des caractères de production ont été caractérisés pour un large éventail de paramètres de l'immunité trois semaines après vaccination contre Mycoplasmahyopneumoniae. Ces paramètres incluent : i) une numération‐formule sanguine et un comptage par cytométrie de flux de cinq sous‐populations leucocytaires caractérisées par la présence à leur surface des marqueurs IgM, TCRγδ, CD4/CD8, CD16/CD2 et CD16/CD172a/MHCII, ii) des paramètres de la RI innée (phagocytose et production in vitro des cytokines IL1B, IL6, IL8, TNF, IL12 etIFNα après stimulation du sang total), iii) des paramètres de RI adaptative (prolifération lymphocytaire, production in vitro descytokines IL2, IL4, IL10 et IFNγ, dosages sériques des immunoglobulines (Ig) totales A, G, M et des IgG spécifiques anti‐Mycoplasmahyopneumoniae) et iv) deux protéines de la phase inflammatoire aiguë (protéine C‐réactive et haptoglobine). Les estimations d'héritabilité atteignent 0,4 en moyenne (SE = 0,1) et 42 des 54 paramètres mesurés ont montré des valeurs d'héritabilité estimées modérées à élevées (≥ 0,2). Ces valeurs confirment que de nombreux paramètres sont sous contrôle génétique et pourraient être inclus dans les programmes de sélection. Les analyses fonctionnelles ont révélé que le transcriptome sanguin est informatif pour une partie des caractères d'immunité mesurés et pourrait être utile pour affiner nos connaissances sur l'immunocompétence chez le porc