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Selection for feed efficiency can impair the animal’s ability to respond to stress. A key driver of this response is the hypothalamo-pituitary-adrenal (HPA) axis, which releases cortisol in response to stressors. Injection of a normalized dose of adrenocorticotropic hormone (ACTH) to stimulate cortisol release by the adrenal cortex is a standardized method to evaluate the activity of the HPA axis independently of the animal’s perception of stress. It has been used to select during three generations a highCortisol line and a lowCortisol line, that had divergent cortisol levels 1 h after ACTH injection (H1, peak of the response). A trial was set up to compare the responses to ACTH of these two lines and those of two other lines divergently selected for residual feed intake (RFI, measure of net feed efficiency) during nine generations. At 6 weeks of age, 48 pigs per line were tested. Blood samples were collected before and 1 (H1) and 4 h after injection (H4) when cortisol is expected to return to basal level. In the Cortisol lines, plasma cortisol was multiplied by 2 (P

International audience; This study aims at assessing the contribution of the additive and dominance genomic variances to the phenotypic expression of several purebred Piétrain and crossbred (Piétrain × Large White) pig performances. A total of 636 purebred and 720 crossbred male piglets were phenotyped for 22 traits that can be classified into the trait groups growth rate and feed efficiency, carcass composition, meat quality, behaviour, boar taint and puberty. Additive and dominance variances estimated in univariate genotypic models including additive and dominance genotypic effects and a genomic inbreeding covariate allowed us to retrieve the additive and dominance SNP variances for purebred and crossbred performances. These estimated variances were used, together with the allelic frequencies of the parental populations, to obtain additive and dominance variances in terms of genomic breeding values and dominance deviations. Estimates of additive genetic variances across traits were consistent with previous results without dominance indicating that additive and dominance genetic effects were non-confounded. Some traits showed a relevant amount of dominance genetic variance in both populations (i.e. growth rate 8%, feed conversion ratio 9-12%, backfat thickness 14-12%, lean meat 10-8%, carcass lesions 9%, in purebreds and crossbreds, respectively) or increased amounts in crossbreds (i.e. ham cut 8-13%, loin 7-16%, pH semimembranosus 13-18%, pH Longissimus dorsi 9-14%, dressing yield 5-15%, androstenone 5-13% and estradiol 6-11%). Results suggest that accounting for dominance in the models of these traits could lead to an increased GEBV accuracy and that using crossbred information can be beneficial to evaluate purebred candidates to selection for crossbred performance. Further research will compare additive and dominance marker effects between crossbred and purebred performances.

International audience

XVII Jornadas sobre Producción AnimalISBN: 978-84-697-3065-2; This study aims at assessing the contribution of the additive and dominance genomic variances to the phenotype expression of several purebred Piétrain and crossbred (Piétrain x large White) pig performances. A total of 636 purebred and 720 crossbred male piglets were phenotyped for 22 traits that can be classified into growth rate and feed efficiency, carcass composition, meat quality, behavior, boar taint and puberty groups of traits. Additive and dominance variances estimated in univariate genotypic models including additive and dominance genotypic effects allowed us to retrieve the additive and dominance SNP variances. These ones were used, together with the allelic frequencies of the parental populations, to obtain additive and dominance variances in terms of genetic breeding values and dominance deviations. Some traits showed relevant amount of dominance genetic variance in both populations (i.e. backfat thickness, pH) or increased amount in crossbreds (i.e. ham cut, loin and dressing yield) suggesting that accounting for dominance in the models of these traits could lead to an increased GEBV accuracy and that using crossbred information can be beneficial to evaluate purebred candidates to selection for crossbred performance.

La sélection génomique est un nouvel outil permettant d’augmenter la précision du choix des reproducteurs porcins par la prise en compte de l’information de leur génome dans l’évaluation génétique. Une population de référence de 1348 reproducteurs génotypés sur puces SNP haute - densité (panels Illumina 60K etGeneSeek Genomic Profiler Porcine HD) a été constituée dans la population Collective Landrace Français. A partir de ces données, une étude de validation a permis de mettre en évidence des gains de précision substantiels dans le choix des reproducteurs à l’issue du contrôle en ferme par rapport à l’évaluation génétique conventionnelle de type BLUP Modèle Animal. Les gains de fiabilité des valeurs génétiques, de l’ordre de 30% à 50%, ont été estimés pour des critères de reproduction clés comme le nombre de porcelets nés vivants, le nombre de porcelets sevrés ou le poids moyen des porcelets à la naissance. En effet, sur ces critères, aucune performance propre n’est disponible pour les candidats au moment de la sélection. L’information génomique se révèle donc être une information importante pour identifier les meilleurs reproducteurs. Sur la base de ces résultats, la sélection génomique a été déployée dans le schéma de sélection Landrace en 2016. Chaque semaine, une évaluation génomique combinant performances, généalogies et génotypages est réalisée. Les candidats à la sélection sont d’abord triés sur valeur génétique conventionnelle avant d’être génotypés pour choisir sur valeur génomique les reproducteurs à conserver pour le noyau de sélection.

Predictive ability of a single-step terminal-cross model. 67. Annual Meeting of the European Federation of Animal Science (EAAP)

International audience

Microbiote intestinal chez le porc : paramètres génétiques de sa composition et liens avec des caractères immunitaires. 48. Journées de la Recherche Porcine

International audience; In pig breeding schemes, the traits of interest are measured in the grandparent or parent populations on purebred animals. However, the progress in these pure breeds should be expressed in the crossbred offspring. It is generally expected that the genetic relationships between traits measured on purebred and crossbred animals are high for growth traits and body composition. The purpose of the study was to estimate the genetic correlations between performances recorded in pure and crossed animals on a large number of traits related to production, quality, welfare and health, i.e. growth rate, carcass composition, meat quality including boar taint, sex hormones, blood parameters, bodily injury and leg weakness. About 1,600 animals were included in the study, either purebred Piétrain or crossbred Piétrain x Large White. For the majority of production traits such as growth and carcass composition, genetic correlations between purebred and crossbred were close to 1 (between 0.7 and 1, with a standard error between 0.05 and 0.20). Some traits had lower correlation parameters such as the number of leukocytes (rg = 0.5 ± 0.30) or the number of injuries at the beginning of fattening (rg = -0.14 ± 0.40).

L’étude repose sur l’analyse de l’épaisseur de lard au tomographe RX d’animaux de 13 types génétiques : des races pures de type Piétrain, des croisés deux voies de type Piétrain x Large-White et des porcs charcutiers. Pour chacune des 280 demi-carcasses analysées, les épaisseurs moyennes de lard sont calculées sur la longueur totale de la carcasse et sur trois zones anatomiques (épaule, longe, jambon). Des différences d’épaisseur de lard sont observées entre zones anatomiques et entre groupes de types génétiques. Les porcs de races pures sont plus maigres que les porcs croisés deux voies, eux-mêmes plus maigres que les porcs charcutiers. Les épaisseurs de lard décroissent de l’épaule au jambon. Les plus faibles coefficients de variation des mesures d’épaisseur de lard sont observés au niveau de la longe. Les trois génotypes au locus halothane sont représentés dans cette étude. Des différences significatives entre les animaux NN et Nn sont mises en évidence : les animaux hétérozygotes présentent une épaisseur moyenne de lard plus faible de 0,7 mm par rapport aux homozygotes ; l’écart est de 1 mm au niveau des zones de la longe et de l’épaule (respectivement P < 0,05 et P < 0,01) mais n’est pas significatif au niveau de la zone du jambon. Aucune différence significative n’est observée par rapport au génotype nn, sans doute en raison du faible nombre d’animaux porteurs de ce génotype., The study is based on fat thickness analysis with computed tomography (CT) of animals from 13 genetic types: purebred Piétrain-like breeds, crossbred Piétrain x Large-White types and crossbred fattening pigs. For each of the 280 analyzed half-carcasses, average fat thickness was calculated throughout the carcass as well as in three body parts (shoulder, loin, ham zones). Fat thickness differences were observed between body parts and between groups of genetic types. Purebred animals were leaner than crossbred Piétrain x Large-White types themselves leaner than crossbred fattening pigs. Subcutaneous fat thickness decreased from the shoulder to the ham. The lowest fat thickness variation coefficients were seen for the loin. The three halothane genotypes were represented in this study. Significant differences between NN and Nn animals were highlighted: heterozygote animals presenting 0.7 mm less fat thickness compared with homozygotes; significant differences were seen at the loin (1.1 mm, P < 0.05) and shoulder (1.0 mm, P < 0.01) parts but differences were not significant at the ham. No significant effect was observed in comparison with the nn genotype, probably due to the small number of animals carrying this genotype.

National audience; The study is based on fat thickness analysis with computed tomography (CT) of animals from 13 genetic types: purebred Piétrain-like breeds, crossbred Piétrain x Large-White types and crossbred fattening pigs. For each of the 280 analyzed half-carcasses, average fat thickness was calculated throughout the carcass as well as in three body parts (shoulder, loin, ham zones). Fat thickness differences were observed between body parts and between groups of genetic types. Purebred animals were leaner than crossbred Piétrain x Large-White types themselves leaner than crossbred fattening pigs. Subcutaneous fat thickness decreased from the shoulder to the ham. The lowest fat thickness variation coefficients were seen for the loin. The three halothane genotypes were represented in this study. Significant differences between NN and Nn animals were highlighted: heterozygote animals presenting 0.7 mm less fat thickness compared with homozygotes; significant differences were seen at the loin (1.1 mm, P < 0.05) and shoulder (1.0 mm, P < 0.01) parts but differences were not significant at the ham. No significant effect was observed in comparison with the nn genotype, probably due to the small number of animals carrying this genotype.; L’étude repose sur l’analyse de l’épaisseur de lard au tomographe RX d’animaux de 13 types génétiques : des races pures de type Piétrain, des croisés deux voies de type Piétrain x Large-White et des porcs charcutiers. Pour chacune des 280 demi-carcasses analysées, les épaisseurs moyennes de lard sont calculées sur la longueur totale de la carcasse et sur trois zones anatomiques (épaule, longe, jambon). Des différences d’épaisseur de lard sont observées entre zones anatomiques et entre groupes de types génétiques. Les porcs de races pures sont plus maigres que les porcs croisés deux voies, eux-mêmes plus maigres que les porcs charcutiers. Les épaisseurs de lard décroissent de l’épaule au jambon. Les plus faibles coefficients de variation des mesures d’épaisseur de lard sont observés au niveau de la longe. Les trois génotypes au locus halothane sont représentés dans cette étude. Des différences significatives entre les animaux NN et Nn sont mises en évidence : les animaux hétérozygotes présentent une épaisseur moyenne de lard plus faible de 0,7 mm par rapport aux homozygotes ; l’écart est de 1 mm au niveau des zones de la longe et de l’épaule (respectivement P < 0,05 et P < 0,01) mais n’est pas significatif au niveau de la zone du jambon. Aucune différence significative n’est observée par rapport au génotype nn, sans doute en raison du faible nombre d’animaux porteurs de ce génotype.

Accuracy of genomic selection to improve litter traits in the French Landrace pig population. 67. Annual Meeting of the European Federation of Animal Science (EAAP)

International audience; To get insights into selection criteria for feed efficiency, 2 rabbit lines have been created: the ConsoResidual line was selected for residual feed intake (RFI) with ad libitum feeding and the ADGrestrict line was selected for ADG under restricted feeding. The aim of the present study was to evaluate the impact on carcass and meat quality of the genetic selections. This comparison was performed using 2 different feeding strategies corresponding to the selection design. Carcass and meat quality traits were recorded for the 3 lines (ConsoResidual, ADGrestrict, and an unselected control [generation 0 {G0}]) in the 2 feeding systems (ad libitum and restricted) for 163 animals. Concerning the line effect, the BW at 63 d old was higher for the ADGrestrict line compared with the G0 and ConsoResidual lines (P < 0.0001). There was no line effect on the gastrointestinal tract. The rabbits did not exhibit a different carcass yield but showed different carcass traits. Indeed, the ConsoResidual rabbits had a higher hind leg yield (P < 0.0001) but no difference in the meat-to-bone ratio of the hind leg. On the contrary, the ADGrestrict line had a higher proportion of forelegs plus thoracic cage (P = 0.03). We also found lower perirenal (P < 0.0001) and scapular fat yields (P < 0.0001) in ConsoResidual rabbits. The ADGrestrict line had an intermediate perirenal fat yield compared with the other 2 lines. The G0 line always exhibited higher fat yields. Concerning meat quality, the ConsoResidual rabbits showed a lower ultimate pH (P < 0.0001) and higher water loss (drip and cooking loss; P < 0.002) compared with the G0 and ADGrestrict rabbits. The feeding level had a strong effect on the gastrointestinal tract (P = 0.0004) and the carcass yield (P = 0.001). The latter was decreased in restricted rabbits. The effects of feeding strategy on meat quality were detrimental in the case of restricted feeding. Even if the ultimate pH was slightly higher in restricted rabbits (P = 0.0002), the carcass chilling loss (P = 0.0005) and the drip loss during 6 d (P < 0.0001) were higher. The selection on ADG with restricted access to feed seems to be less adversely correlated with carcass traits and meat quality traits but it leads to an increase in the live weight of the rabbits. Adversely, the selection on RFI, without affecting growth rate, would not modify age at slaughter because growth rate is not affected, but it might induce detrimental effects on meat quality.

International audience; Predicting fat androstenone concentration using a rapid and cheap method applied to live pigs is needed for efficient genetic selection against boar taint. Piétrain x (Large White x Landrace) boars were slaughtered either at 119 ± 4 kg live weight and 168 ± 1 d of age (S1, n = 48) or at 116 ± 4 kg and 174 ± 1 d of age (S2, n = 42). Blood and saliva samples were collected on D 0 (S1: 29 d, S2: 35 d before slaughter) and D 27 (S1: 2 d, S2: 8 d before slaughter) to measure plasma concentrations of estradiol and testosterone and salivary concentration of estrone by EIA. A backfat sample was collected on live pigs by biopsy on D 27 and on carcasses at slaughter to measure concentration of androstenone by HPLC. Testes and Cowper glands were weighed at slaughter after tissue trimming. Data were analyzed using the R MASS package. When necessary, variables were log or square root transformed for normalization. Predictive models of fat androstenone at slaughter were established with the modlin function. Plasma estradiol and fat androstenone on D 27, taken separately, were good predictors of fat androstenone at slaughter (mean R2 between measured and predicted values was 0.48 and 0.43, respectively for each predictor) in S1 pigs. The quality of the prediction decreased between S1 and S2 pigs despite inclusion of salivary estrone in the equation with estradiol. To conclude, plasma estradiol can be considered as a good predictor of fat androstenone at slaughter if the delay between blood collection and slaughter is short.

In crossbreeding schemes, within-line selection of purebred lines mainly aims at improving performance of crossbred progeny in field conditions. The genetic correlation between purebred and crossbred performance is an important parameter to be assessed to ascertain that purebred performance is a good predictor of crossbred performance. With the availability of high density markers, feasibility of using crossbred information for evaluating purebred candidates can be reevaluated. This study implements and applies to real data a single-step terminal-cross model to estimate genetic parameters of several production traits in Pietrain and Pietrain x Large White pigs.Piglets were recorded for growth rate between 35 and 110 kg. Animals were genotyped using the 60K SNP chip. For each trait, purebred and crossbred performances were jointly analyzed. The purebred animals were evaluated through an animal model, whereas the additive genetic effect of a crossbred individual was decomposed into its purebred sire and dam allelic contribution effects. Piétrain genotypes were introduced in genetic evaluation in a single-step procedure. The same model but only accounting for pedigree information was compared to the genomic model in terms of breeding value accuracies obtained from the mixed model equations. Genetic correlation between purebreds and sire allelic contribution to crossbred performance was high (0.84 and 0.79 for the genomic and the pedigree model, respectively). Breeding value accuracies of the genotyped animals obtained with the genomic model outperformed the pedigree model.

Deux lignées de lapins ont été créées pour améliorer leur efficacité alimentaire (EA) entre le sevrage et 63 jours d'âge, selon 2 critères i) la consommation résiduelle (lignée ConsoResiduelle), ii) le gain moyen quotidien en alimentation restreinte (lignée GMQRestreint). La digestion et les rejets de ces lignées ont été comparés à une lignée témoin (G0), en alimentation ad-libitum (AL) ou restreinte de 20% (R). Après 9 générations de sélection, l'indice de consommation est réduit de 0,1 à 0,2 pts (resp. pour ConsoResiduelle et GMQRestreint), et est associé à une meilleure rétention de l'azote (réduction du rejet urinaire). Entre 29 et 63j. d'âge, le rejet azoté est réduit d'environ 12% chez les 2 lignées sélectionnées, alors que le rejet de phosphore n'est pas modifié. La restriction alimentaire produit une meilleure digestion de l'aliment et une meilleure rétention de l'azote (+5pts), et conduit à une réduction de 35% du rejet azoté, et de 50% du rejet de phosphore., Two lines of rabbits were created to improve feed efficiency (FE) between weaning and 63 days of age, according to two criteria i) residual intake (ConsoResiduelle line), ii) the average daily gain with restricted feeding (line GMQRestreint). Digestion and slurry output of these lines were compared to a control line (G0), under ad-libitum feeding (AL) or restricted by 20% (R). After nine generations of selection, the feed conversion ratio is reduced from 0.1 to 0.2 pts (resp. for ConsoResiduelle and GMQRestreint), and is associated with a better nitrogen retention (decreased urine output). Between 29 and 63d old, nitrogen output is reduced by about 12% in the two selected lines, while the output of phosphorus remained unchanged. The feed restriction improved the digestion and the retention of nitrogen (+5 points), and led to a 35% reduction of the nitrogen output and to 50% less phosphorus output.

National audience; Genetic improvement of feed efficiency using two alternate traits compared to feed to gain ratio (FCR) were studied in the growing rabbit: Residual Feed Intake (RFI), to select low ad libitum feed intake independently from production level (ConsoRésiduelle line), and Average Daily Gain (ADGR) under restricted feeding (GMQrestreint line) (80% of ad libitum), to select high ADG under limited fixed feed intake. Responses to selection for the two criteria were similar in the two lines (-0.34 genetic standard deviations (σa) per generation for RFI, +0.29 σa per generation for GMQR line). Responses to selection were -0.30 σa per generation on FCR in both lines. Responses to selection were null on ADG and limited on BW63 in the ConsoRésiduelle line, whereas they were highly significant in the GMQrestreint line. To further examine responses to selection, in generation 9 a comparison of the two selected lines with the G0 control population (using frozen embryos) under ad libitum and restricted feeding was applied to 30 individuals per line and feeding level combination. As a result, both selected lines had a similar improved FCR (2.62±0.02) compared to the G0 line (2.82±0.02), but with a lower feed intake. In return, the GMQrestreint line showed the highest growth. Under restricted feeding, the two selected lines showed a higher daily gain than G0.; Deux caractères ont été sélectionnés afin d’améliorer l’efficacité alimentaire du lapin entre le sevrage et 63 jours d'âge: i) la consommation résiduelle (CR) afin de sélectionner les animaux ayant une consommation ad libitum réduite pour une même vitesse de croissance (lignée ConsoRésiduelle), ii) le gain moyen quotidien en régime alimentaire restreint (GMQR) afin de sélectionner les animaux ayant une croissance élevée à ingéré fixe (lignée GMQrestreint). Les réponses à la sélection sont similaires pour les deux critères de sélection (-0,34 écarttype génétique pour la CR et 0,29 écart-type génétique pour le GMQR) Pour l’indice de consommation, la réponse à la sélection était de -0,30 écart-type génétique dans les deux lignées. Les réponses à la sélection étaient nulles pour le GMQ et faible pour le poids à 63 jours dans la lignée ConsoRésiduelle, tandis qu’elles étaient fortement significatives dans la lignée GMQrestreint. A la neuvième génération, les deux lignées sélectionnées ont été comparées à une population témoin G0, issue d’embryons congelés, pour les deux niveaux alimentaires, ad libitum et restreint. Quel que soit le niveau alimentaire, les 2 lignées sélectionnées ont un indice de consommation significativement plus faible (2,62±0,02) que la lignée G0 (2,82±0,02), avec toutefois des quantités d’aliment ingéré et des poids à 63 jours différents. En régime ad libitum, la lignée ConsoRésiduelle présente la même croissance que la lignée G0, mais avec une moindre consommation d’aliment. En revanche, la lignée GMQrestreint montre la plus forte croissance. En régime restreint, les deux lignées sélectionnées ont une croissance plus forte que la lignée G0.

Deux caractères ont été sélectionnés afin d’améliorer l’efficacité alimentaire du lapin entre le sevrage et 63 jours d'âge: i) la consommation résiduelle (CR) afin de sélectionner les animaux ayant une consommation ad libitum réduite pour une même vitesse de croissance (lignée ConsoRésiduelle), ii) le gain moyen quotidien en régime alimentaire restreint (GMQR) afin de sélectionner les animaux ayant une croissance élevée à ingéré fixe (lignée GMQrestreint). Les réponses à la sélection sont similaires pour les deux critères de sélection (-0,34 écarttype génétique pour la CR et 0,29 écart-type génétique pour le GMQR) Pour l’indice de consommation, la réponse à la sélection était de -0,30 écart-type génétique dans les deux lignées. Les réponses à la sélection étaient nulles pour le GMQ et faible pour le poids à 63 jours dans la lignée ConsoRésiduelle, tandis qu’elles étaient fortement significatives dans la lignée GMQrestreint. A la neuvième génération, les deux lignées sélectionnées ont été comparées à une population témoin G0, issue d’embryons congelés, pour les deux niveaux alimentaires, ad libitum et restreint. Quel que soit le niveau alimentaire, les 2 lignées sélectionnées ont un indice de consommation significativement plus faible (2,62±0,02) que la lignée G0 (2,82±0,02), avec toutefois des quantités d’aliment ingéré et des poids à 63 jours différents. En régime ad libitum, la lignée ConsoRésiduelle présente la même croissance que la lignée G0, mais avec une moindre consommation d’aliment. En revanche, la lignée GMQrestreint montre la plus forte croissance. En régime restreint, les deux lignées sélectionnées ont une croissance plus forte que la lignée G0., Genetic improvement of feed efficiency using two alternate traits compared to feed to gain ratio (FCR) were studied in the growing rabbit: Residual Feed Intake (RFI), to select low ad libitum feed intake independently from production level (ConsoRésiduelle line), and Average Daily Gain (ADGR) under restricted feeding (GMQrestreint line) (80% of ad libitum), to select high ADG under limited fixed feed intake. Responses to selection for the two criteria were similar in the two lines (-0.34 genetic standard deviations (σa) per generation for RFI, +0.29 σa per generation for GMQR line). Responses to selection were -0.30 σa per generation on FCR in both lines. Responses to selection were null on ADG and limited on BW63 in the ConsoRésiduelle line, whereas they were highly significant in the GMQrestreint line. To further examine responses to selection, in generation 9 a comparison of the two selected lines with the G0 control population (using frozen embryos) under ad libitum and restricted feeding was applied to 30 individuals per line and feeding level combination. As a result, both selected lines had a similar improved FCR (2.62±0.02) compared to the G0 line (2.82±0.02), but with a lower feed intake. In return, the GMQrestreint line showed the highest growth. Under restricted feeding, the two selected lines showed a higher daily gain than G0.

National audience; Two lines of rabbits were created to improve feed efficiency (FE) between weaning and 63 days of age, according to two criteria i) residual intake (ConsoResiduelle line), ii) the average daily gain with restricted feeding (line GMQRestreint). Digestion and slurry output of these lines were compared to a control line (G0), under ad-libitum feeding (AL) or restricted by 20% (R). After nine generations of selection, the feed conversion ratio is reduced from 0.1 to 0.2 pts (resp. for ConsoResiduelle and GMQRestreint), and is associated with a better nitrogen retention (decreased urine output). Between 29 and 63d old, nitrogen output is reduced by about 12% in the two selected lines, while the output of phosphorus remained unchanged. The feed restriction improved the digestion and the retention of nitrogen (+5 points), and led to a 35% reduction of the nitrogen output and to 50% less phosphorus output.; Deux lignées de lapins ont été créées pour améliorer leur efficacité alimentaire (EA) entre le sevrage et 63 jours d'âge, selon 2 critères i) la consommation résiduelle (lignée ConsoResiduelle), ii) le gain moyen quotidien en alimentation restreinte (lignée GMQRestreint). La digestion et les rejets de ces lignées ont été comparés à une lignée témoin (G0), en alimentation ad-libitum (AL) ou restreinte de 20% (R). Après 9 générations de sélection, l'indice de consommation est réduit de 0,1 à 0,2 pts (resp. pour ConsoResiduelle et GMQRestreint), et est associé à une meilleure rétention de l'azote (réduction du rejet urinaire). Entre 29 et 63j. d'âge, le rejet azoté est réduit d'environ 12% chez les 2 lignées sélectionnées, alors que le rejet de phosphore n'est pas modifié. La restriction alimentaire produit une meilleure digestion de l'aliment et une meilleure rétention de l'azote (+5pts), et conduit à une réduction de 35% du rejet azoté, et de 50% du rejet de phosphore.

International audience; The aims of this study were to investigate variation in content of androstenone (AND), skatole (SKA), and indole (IND), quantified in adipose tissue of intact male pigs at 160 d of age (105 kg BW) and 220 d of age (155 kg BW), to estimate genetic parameters and to investigate the genetic relationships for AND, SKA, IND, and growth traits. A sample of adipose tissue was collected in vivo, using a biopsy device, from the neck of 500 intact males at the 2 ages and at slaughter from the ham of 100 of the investigated animals. Backfat depth was measured at 220 d of age, whereas BW was recorded at each sampling. Quantification of AND, SKA, and IND was performed by HPLC with fluorescence detection. Estimates of genetic parameters were obtained through Bayesian analyses after logarithmic transformations of original measures. Contents of boar taint compounds (BTC) measured at 220 d were higher than those at 160 d of age. Correlations between contents of BTC in backfat and ham fat ranged from 0.7 (IND) to 0.88 (SKA). Medium-high h were estimated for BTC at both ages, but estimates at 220 d (0.58, 0.60, and 0.69 for AND, SKA, and IND, respectively) were greater than those at 160 d. The genetic correlation between contents at 160 and 220 d of each BTC was positive, but the probability that such estimates were greater than 0.8 was very low, indicating that contents at 160 and 220 d were traits controlled by different genetic backgrounds. Different rankings were observed when breeding values for the content at 160 and 220 d of age were used to rank animals. As a consequence, performance testing programs for BTC should be based preferably on phenotypes measured at 220 d of age. Weak genetic correlations were observed between content of BT compounds and growth traits (BW, backfat depth, and daily gain from 160 to 220 d of age), indicating that selective breeding to reduce the risk of tainted pork is expected to exert trivial effects on growth performance and fat deposition. Results indicate that prevalence of BTC is high in mature and heavy pigs relative to young and light pigs. High heritability; positive genetic correlations between AND, SKA, and IND; and trivial effects on growth traits suggest that reduction of BTC through selective breeding is feasible and exploitable as an alternative to surgical castration also for pigs slaughtered at heavy BW.

This study focuses on 100 boars from three Pietrain varieties: 74 V1, 10 V2 and 16 V3. On average, data wererecorded on 90 ejaculates collected in artificial insemination centers and boar taint measured on 15.4 entiremale offspring, half purebred and half Pietrain × Large-White type. Offspring were reared at INRA UETP(Le Rheu, France) up to 110 kg. Boar taint risk was assessed by androstenone and skatole measurements infat collected at the slaughterhouse. Sperm production data were corrected for the production site, the age andthe collection frequency using a generalized linear mixed model to estimate an average sperm productioncount per boar and ejaculate. Boar taint odor risk was on the whole low in the tested population. Consideringthe three Pietrain varieties altogether, boars with the highest sperm production had a lower proportion ofoffspring without risk of odor compared to boars with low sperm production: the boars ranked in the topquartile of sperm production had 14% less offspring without odor (i.e. androstenone

Breeding intact boars is a promising alternative to the surgical castration of piglets. Genetic selection should make it possible tosolve problems due to boar taint and aggressiveness. About 1600 Pietrain type (purebred) or Pietrain x Large White type(crossbred) boars were raised in a testing station. Blood samples were collected for measuring two sex hormones (testosterone,estradiol), and indicators of the inflammatory status (C‐reactive protein: CRP, Pig Major Acute‐Phase Protein: pigMAP, bloodformula). Animals were slaughtered nine days later, measured for boar taint compounds (androstenone, skatole) and skin lesionson carcass, an indicator of aggressiveness. For both genetic types, heritability was moderate for sex hormones (from 0.17 to 0.29)and skatole (purebred: 0.24, crossbred: 0.37), and high for androstenone (0.63 and 0.70). Genetic correlations between sexhormones and boar taint compounds were moderate to high (from 0.31 to 0.95). Heritability was moderate for CRP (0.24 and 0.46)and very low for pigMAP (0.06 and 0.05). Numbers of leucocytes had moderate to high heritabilities according to the genetic type(0.21 and 0.52). Heritability of skin lesions was moderate for both genetic types (0.31). Genetic correlations were negativebetween sex hormones and inflammatory measures (from ‐0.46 to ‐0.05), positive between testosterone and number of lesions(0.43 and 0.53), and low between androstenone and lesions (‐0.06 and ‐0.17). Therefore, it would be possible to select boars ontheir concentration in plasma sex hormones to decrease boar taint and aggressiveness, without important consequences on theinflammatory system.

Lors d’un problème de santé, les ressources nutritionnelles d’un animal en croissance sont limitées par la réduction de son ingestion, le conduisant à détourner les nutriments de sa fonction de croissance vers ses fonctions de défense. Les porcs actuels, à fort potentiel de croissance, semblent moins robustes que les races anciennes à croissance plus lente, mais cette relation a été peu étudiée. Ce travail vise à tester l’effet de la vitesse de croissance des porcs sur les pertes/saisies en engraissement, et des indicateurs d’inflammation. Une base de données a été créée en regroupant les performances et les pertes/saisies de 5 863 porcs en engraissement issus de trois stations expérimentales de l’INRA. Dans l’une d’elles, les causes des pertes étaient enregistrées et des prélèvements de sang ont été réalisés avant l’abattage des porcs (110 kg). Au total, 7% des porcs sont perdus en engraissement ou saisis à l’abattoir et la répartition dans le temps de ces pertes diffère entre les stations. Un poids à la naissance et une croissance en maternité élevées favorisent une consommation et une croissance élevées jusqu’en fin d’engraissement sans être néfastes à la survie, ni prédictif d’une saisie à l’abattoir. L’hypothèse d’une plus grande fragilité des porcs à croissance rapide n’est pas vérifiée, mais des corrélations négatives entre performances et nombre de cellules immunitaires et positives avec l’hématocrite apparaissent dans cette étude. D’autres études sont nécessaires pour identifier des indicateurs prédictifs des pertes d’animaux en engraissement ou à l’abattage., During health disorders, growing animals have to divert nutrients from growth to defense functions despite a reduction in nutrient resources because of a reduced voluntary feed intake. Modern high‐performance pigs are suspected of being less robust than former low‐performance breeds but this relation has been poorly investigated. The present work has been designed to study the effect of growth rate in growing‐fattening pigs on the losses, on the one hand, and inflammatory markers, on the other hand. A database was built using performances and losses of 5 863 growing‐fattening pigs in three experimental units of INRA. In one of the three units, causes of losses were recorded and blood samples were collected before slaughter (110 kg). In total, 7% of pigs were lost during the fattening period or at slaughter (carcass condemnation) and the time distribution of losses varied between research units. A high birth weight combined with a rapid pre‐weaning growth were associated with a high feed intake and rapid growth until the end of the fattening period without detrimental effect on survival, nor on carcass condemnation. The assumption of a greater weakness of high‐performance pigs is not verified, but negative correlations between performance and immune cell counts positive with hematocrit appear in the present study. Other research is necessary to identify predictive indicators of pig losses during the fattening period and at slaughter.

Relation entre la production spermatique et le risque d’odeur de mâle entier des descendants de race pure ou croisés L’étude porte sur 100 verrats issus de trois variétés de Piétrain codifiées V1 à V3 (74 verrats V1, 10 V2 et 16 V3). Pour chaque verrat, les données de 90 prélèvements de semence réalisés en CIA et des dosages de composés odorants sur en moyenne 15,4 descendants sont disponibles. Les descendants, la moitié de race pure, l’autre moitié de type Piétrain x Large‐White, ont été élevés à l’INRA UETP (Le Rheu) jusqu’à 110 kg. Les risques d’odeur de mâle entier sont évalués par dosage d’androsténone et de scatol dans le gras prélevé à l’abattoir. Les données de production spermatique sont corrigées pour les effets du site de production, de l’âge et de la fréquence des prélèvements pour estimer une production spermatique moyenne par verrat et par éjaculat. Les risques d’odeur de mâle entier sont globalement faibles dans la population étudiée. Toutes variétés de Piétrain confondues, les verrats avec les plus fortes productions spermatiques ont une proportion plus faible de descendants sans risque d’odeur par rapport aux verrats à faible production spermatique. La production spermatique des pères des descendants à forte teneur en androsténone est en moyenne plus élevée que celle des pères des descendants à faible teneur. Les différences sont plus marquées avec les descendants croisés qu’avec les descendants de race pure. Les conclusions sont similaires avec les pères V1 seuls mais les écarts sont plus faibles et moins significatifs qu’avec le dispositif complet. Les écarts ne sont globalement pas significatifs avec les pères V2 et V3 seuls qui présentent des effectifs plus faibles., Relationship between sperm production and boar taint risk of purebred or crossbred entire offspring This study focuses on 100 boars from three Pietrain varieties: 74 V1, 10 V2 and 16 V3. On average, data on 90 ejaculates collected on AI centers and boar taint measurement on 15.4 offspring are available. Offspring, half purebred and half Pietrain x Large‐White type were reared at INRA UETP (Le Rheu, France) up to 110 kg. Boar taint risk is assessed by androstenone and skatole measurements in fat taken at the slaughterhouse. Sperm production data are corrected for the production site, the age and the collection frequency to estimate an average sperm production count per boar and ejaculate. Boar taint odor risk showed to be low on average in the tested population. Considering the three Pietrain varieties altogether, boars with the highest sperm production have a lower proportion of offspring without risk of odor compared to boars with low sperm production. The sperm production of the fathers of pigs with high androstenone content in fat is on average higher than that of the fathers of low androstenone content offspring. Differences are more pronounced on crossbred offspring than on purebred ones. The conclusions are similar with V1 fathers alone but differences are smaller and less significant than with the complete experimental design. The differences are generally not significant with V2 and V3 varieties alone which are in lower numbers.

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Breeding intact boars is a promising alternative to surgical castration of piglets. Genetic selection should enable farmers to solve problems due to boar taint and aggressiveness while taking into account potential consequences on other traits of interest. The aim of the study was to estimate genetic relations between sexual development, boar taint, health, and aggressiveness. About 1,600 Pietrain (purebred) or Pietrain × Large White (crossbred) boars were raised in a testing station. Blood samples were collected at about 105 kg BW for measuring sex hormones (testosterone and estradiol) and indicators of the inflammatory status (C-reactive protein [CRP], pig major acute-phase protein [pigMAP], and blood formula). Animals were slaughtered 9 d later and measured for boar taint compounds present in fat (androstenone and skatole) and skin lesions on carcass, an indicator of aggressiveness. For both genetic types, heritability was moderate for sex hormones (from 0.17 to 0.29) and skatole (0.24 for purebred and 0.37 for crossbred) and high for androstenone (0.63 and 0.70 for purebred and crossbred, respectively). Genetic correlations between sex hormones and boar taint compounds were moderate to high (from 0.31 to 0.95). Heritability was moderate for CRP (0.24 and 0.46 for purebred and crossbred, respectively) and very low for pigMAP (0.06 and 0.05 for purebred and crossbred, respectively. Numbers of leukocytes had moderate to high heritabilities according to the genetic type (from 0.21 to 0.52). Heritability of skin lesions was moderate for both genetic types (0.31). Genetic correlations were negative between sex hormones and inflammatory measures (from -0.46 to -0.05), positive between testosterone and number of lesions (0.43 and 0.53 for purebred and crossbred, respectively), and low between androstenone and lesions (-0.06 and -0.17 for purebred and crossbred, respectively). Overall, both breeds of pigs had very similar estimations of heritabilities, but estimates of genetic correlations were different for some pairs of traits. It would be possible to select boars based on their plasma concentration of sex hormones to decrease boar taint and aggressiveness without important consequences on the immune response. However, because of the strong links between boar taint and reproductive function, the possible consequences on the reproductive performance should be evaluated.

International audience; In the search for biological basis of robustness, this study aimed (i) at the determination of the heritability of the cortisol response to ACTH in juvenile pigs, using restricted maximum likelihood methodology applied to a multiple trait animal model, and (ii) at the study of the relationships between basal and stimulated cortisol levels with corticosteroid-binding globulin (CBG), IGF-I and haptoglobin, all important players in glucose metabolism and production traits. At 6 weeks of age, 298 intact male and female piglets from 30 litters (30 dams and 30 boars) were injected with 250 µg ACTH(1–24) (Synacthen). Blood was taken before ACTH injection to measure basal levels of cortisol, glucose, CBG, IGF-I and haptoglobin, and 60 min later to measure stimulated cortisol levels and glucose. Cortisol increased 2.8-fold after ACTH injection, with a high correlation between basal and stimulated levels (phenotypic correlation, rp=0.539; genetic correlation, rg=0.938). Post-ACTH cortisol levels were highly heritable (h2=0.684) and could therefore be used for genetic selection of animals with a more reactive hypothalamic–pituitary–adrenocortical axis. CBG binding capacity correlated with cortisol levels measured in basal conditions in males only. No correlation was found between CBG binding capacity and post-ACTH cortisol levels. Basal IGF-I concentration was positively correlated with BW at birth and weaning, and showed a high correlation with CBG binding capacity with a strong sexual dimorphism, the correlation being much higher in males than in females. Basal haptoglobin concentrations were negatively correlated with CBG binding capacity and IGF-I concentrations. Complex relationships were also found between circulating glucose levels and these different variables that have been shown to be related to glucose resistance in humans. These data are therefore valuable for the genetic selection of animals to explore the consequences on production and robustness traits, but also point at pigs as a relevant model to explore the underlying mechanisms of the metabolic syndrome including the contribution of genetic factors.

Le néologisme « agro-écologie » est apparu dans la littérature dans les années 30, d’abord pour désigner une discipline scientifique au carrefour de l’écologie et de l’agronomie, puis à partir des années 70 un ensemble de pratiques et un mouvement social en réaction à l’intensification de l’agriculture (Wezel et al., 2009). Francis et al. (2003) ont encore élargi cette définition en considérant l’ensemble des dimensions environnementales et socio-économiques à l’échelle des filières. Dans son acception scientifique, qui est l’angle choisi dans cette étude, l’agro-écologie se définit comme l’application des concepts et principes de l’écologie à la conception et à la gestion d’agroécosystèmes durables. La question du bouclage des cycles pour limiter les intrants et les pollutions par une meilleure réutilisation des sorties des différents ateliers est au coeur de ces problématiques. On vise également un recours accru à des régulations biologiques et écologiques que l’on cherche à piloter au mieux des attendus de l’élevage. Ceci implique de prendre en compte la diversité biologique à tous ses niveaux d'organisation, de comprendre et d’utiliser les capacités adaptatives des animaux et les interactions biotiques dans les agroécosystèmes, en considérant les systèmes de culture ou les systèmes d'élevage comme des écosystèmes particuliers (Dumont et al. 2013). Ainsi, l’agro-écologie s’inscrit-elle dans un mouvement de fond autour du « Comment produire autrement ? » dans des systèmes de production dont on cherche à concilier les performances techniques, environnementales, économiques et sociales. Lancé le 18 décembre 2012, le Projet Agro-Ecologique pour la France (PAEF) vise à conjuguer l’ensemble de ces performances tant au niveau de l'exploitation qu’au niveau collectif (territoires, filières, etc.). Il s’agit d’engager une évolution des systèmes de production, qui remette l’agronomie au coeur des pratiques, pour combiner ces différentes performances. La Loi n° 2014-1170 du 13 octobre 2014 dite Loi d'avenir pour l'agriculture, l'alimentation et la forêt en donne la définition suivante : « Les politiques publiques visent à promouvoir et à pérenniser les systèmes de production agro-écologiques, dont le mode de production biologique, qui combinent performance économique, sociale, notamment au travers d’un haut niveau de protection sociale, environnementale et sanitaire. Ces systèmes privilégient l'autonomie des exploitations agricoles et l'amélioration de leur compétitivité, en maintenant ou en augmentant la rentabilité économique, en améliorant la valeur ajoutée des productions et en réduisant la consommation d'énergie, d'eau, d'engrais, de produits phytopharmaceutiques et de médicaments vétérinaires, en particulier les antibiotiques. Ils sont fondés sur les interactions biologiques et l'utilisation des services écosystémiques et des potentiels offerts par les ressources naturelles, en particulier les ressources en eau, la biodiversité, la photosynthèse, les sols et l'air, en maintenant leur capacité de renouvellement du point de vue qualitatif et quantitatif. Ils contribuent à l'atténuation et à l'adaptation aux effets du changement climatique.

Le néologisme « agro-écologie » est apparu dans la littérature dans les années 30, d’abord pour désigner une discipline scientifique au carrefour de l’écologie et de l’agronomie, puis à partir des années 70 un ensemble de pratiques et un mouvement social en réaction à l’intensification de l’agriculture (Wezel et al., 2009). Francis et al. (2003) ont encore élargi cette définition en considérant l’ensemble des dimensions environnementales et socio-économiques à l’échelle des filières. Dans son acception scientifique, qui est l’angle choisi dans cette étude, l’agro-écologie se définit comme l’application des concepts et principes de l’écologie à la conception et à la gestion d’agroécosystèmes durables. La question du bouclage des cycles pour limiter les intrants et les pollutions par une meilleure réutilisation des sorties des différents ateliers est au coeur de ces problématiques. On vise également un recours accru à des régulations biologiques et écologiques que l’on cherche à piloter au mieux des attendus de l’élevage. Ceci implique de prendre en compte la diversité biologique à tous ses niveaux d'organisation, de comprendre et d’utiliser les capacités adaptatives des animaux et les interactions biotiques dans les agroécosystèmes, en considérant les systèmes de culture ou les systèmes d'élevage comme des écosystèmes particuliers (Dumont et al. 2013). Ainsi, l’agro-écologie s’inscrit-elle dans un mouvement de fond autour du « Comment produire autrement ? » dans des systèmes de production dont on cherche à concilier les performances techniques, environnementales, économiques et sociales. Lancé le 18 décembre 2012, le Projet Agro-Ecologique pour la France (PAEF) vise à conjuguer l’ensemble de ces performances tant au niveau de l'exploitation qu’au niveau collectif (territoires, filières, etc.). Il s’agit d’engager une évolution des systèmes de production, qui remette l’agronomie au coeur des pratiques, pour combiner ces différentes performances. La Loi n° 2014-1170 du 13 octobre 2014 dite Loi d'avenir pour l'agriculture, l'alimentation et la forêt en donne la définition suivante : « Les politiques publiques visent à promouvoir et à pérenniser les systèmes de production agro-écologiques, dont le mode de production biologique, qui combinent performance économique, sociale, notamment au travers d’un haut niveau de protection sociale, environnementale et sanitaire. Ces systèmes privilégient l'autonomie des exploitations agricoles et l'amélioration de leur compétitivité, en maintenant ou en augmentant la rentabilité économique, en améliorant la valeur ajoutée des productions et en réduisant la consommation d'énergie, d'eau, d'engrais, de produits phytopharmaceutiques et de médicaments vétérinaires, en particulier les antibiotiques. Ils sont fondés sur les interactions biologiques et l'utilisation des services écosystémiques et des potentiels offerts par les ressources naturelles, en particulier les ressources en eau, la biodiversité, la photosynthèse, les sols et l'air, en maintenant leur capacité de renouvellement du point de vue qualitatif et quantitatif. Ils contribuent à l'atténuation et à l'adaptation aux effets du changement climatique.

Distribution of the rank of the significant adjusted P -values in the tests for DE transcripts between t = 0 and t = + 1, t = 0 and t = + 4 and t = 0 and t = + 24 ‘.pdf’ file. P-values are smaller at t=+1 and t=+4 than at t=+24 implying that the transcripts were overall more differentially expressed between t=0 and t=+1 and between t=0 and t=+4 than between t=0 and t=+24. (PDF 4 kb)

International audience; A total of 654 purebred Piétrain entire male pigs and 716 crossbred Piétrain × Large White entire male pigs issued from about 70 Piétrain sires were tested in a French test station for production traits (feed intake, feed efficiency, growth rate, carcass composition and meat quality). All were genotyped with the 60K Porcine SNPchip. Genome wide association studies were run using linear mixed models with a genomic kinship matrix to account for relatedness between individuals, and the fixed effect of each SNP was tested separately. In a first step, separate analyses of the two populations showed suggestive results (P

Breeding intact boars is a promising alternative to the surgical castration of piglets. Genetic selection should make it possible to solve problems due to boar taint and aggressiveness. About 1600 Pietrain type (purebred) or Pietrain x Large White type (crossbred) boars were raised in a testing station. Blood samples were collected for measuring two sex hormones (testosterone, estradiol), and indicators of the inflammatory status (C‐reactive protein: CRP, Pig Major Acute‐Phase Protein: pigMAP, blood formula). Animals were slaughtered nine days later, measured for boar taint compounds (androstenone, skatole) and skin lesions on carcass, an indicator of aggressiveness. For both genetic types, heritability was moderate for sex hormones (from 0.17 to 0.29) and skatole (purebred: 0.24, crossbred: 0.37), and high for androstenone (0.63 and 0.70). Genetic correlations between sex hormones and boar taint compounds were moderate to high (from 0.31 to 0.95). Heritability was moderate for CRP (0.24 and 0.46) and very low for pigMAP (0.06 and 0.05). Numbers of leucocytes had moderate to high heritabilities according to the genetic type (0.21 and 0.52). Heritability of skin lesions was moderate for both genetic types (0.31). Genetic correlations were negative between sex hormones and inflammatory measures (from ‐0.46 to ‐0.05), positive between testosterone and number of lesions (0.43 and 0.53), and low between androstenone and lesions (‐0.06 and ‐0.17). Therefore, it would be possible to select boars on their concentration in plasma sex hormones to decrease boar taint and aggressiveness, without important consequences on the inflammatory system.

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Les hormones cortico‐surrénaliennes (cortisol chez le porc), essentielles pour la survie, jouent un rôle important dans les réactions de stress, la régulation du métabolisme, l’immunité, la reproduction, l’équilibre hydro‐minéral, etc. Chez le porc, un axe corticotrope hyperactif a un effet défavorable sur les caractères de production. Par contre, quelques études ont montré l’influence positive de l’activité corticotrope sur des caractères de robustesse comme la survie néonatale, la tolérance à la chaleur et la résistance aux maladies. Dans la fonction corticotrope, le niveau de réponse du cortex surrénalien à l’ACTH (hormone hypophysaire) est une source importante de variabilité. Dans une étude familiale portant sur 30 portées de porcelets Large White étudiés à 6 semaines d’âge, l’héritabilité de la concentration plasmatique de cortisol mesurée 1 heure après l’injection de 250 μg d’ACTH a été estimée à 0,68 ± 0,09. Une corrélation génétique positive (0,32 ± 0,13) a été estimée avec la concentration en haptoglobine (inflammation) alors que la corrélation génétique avec la concentration d’IGF‐I (croissance et métabolisme) était faiblement négative (‐0,16 ± 0,18). La semence des 14 verrats dont les réponses étaient les plus extrêmes en cortisol 1 heure après injection d’ACTH (sept verrats aux réponses les plus faibles, sept verrats aux réponses les plus élevées) a été utilisée pour inséminer 62 truies. La réponse à l’ACTH des porcelets des deux lignées obtenues a largement divergé dès cette première génération (105 vs 121 ng/mL, écart‐type 22 ng/mL, soit une différence entre lignées de 0,73 écart‐type). L’héritabilité calculée dans cette expérience était de 0,77 (± 0,15), confirmant les résultats obtenus précédemment., The adrenocortical hormones (cortisol in pigs), essential for survival, play an important role in stress responses, regulation of metabolism, immunity, reproduction, hydro‐mineral balance, etc. In pigs, a hyperactive hypothalamic‐pituitary‐adrenocortical (HPA) axis has a negative effect on production traits. Some studies have shown the positive influence of HPA axis activity on robustness traits such as neonatal survival, heat tolerance and disease resistance. In HPA axis function, the level of the adrenal cortex response to ACTH (pituitary hormone) is an important source of variability. In a family study of 30 litters of Large White pigs studied at 6 weeks of age, the heritability of plasma cortisol measured 1 hour after injection of 250 μg of ACTH was estimated at 0.68 ± 0.09. A positive genetic correlation (0.32 ± 0.13) was estimated with the haptoglobin concentration (inflammation) while the genetic correlation with IGF‐I concentration (growth and metabolism) was slightly negative (‐0.16 ± 0.18). The semen of the 14 boars with the most extreme responses in cortisol to ACTH 1 hour after injection (seven boars with lowest responses, seven boars with highest responses), was used to inseminate 62 sows. The response to ACTH in piglets of the two lines largely diverged from the first generation of selection (105 vs. 121 ng / mL, standard deviation 22 ng / mL, i.e. a difference between lines of 0.73 standard deviation). The heritability value estimated in this experiment was 0.77 (± 0.15), confirming the previous results.

The objective of this study was to assess the feasibility of selecting for functional longevity in rabbits, defined as an ability to delay involuntary culling. Functional longevity was measured as the total number of AI performed after the first kindling. Breeding values were estimated using a discrete survival model. Male parents were selected on the basis of their progeny test results, and the efficiency of selection was estimated in the second generation, as was the correlated response on reproduction traits. A total of 48 males were progeny tested, based on the longevity of 10 daughters bred in 2 different farms. Based on their estimated genetic merit, 5 "high longevity" (HL) and 5 "low longevity" (LL) males were selected divergently and produced a new generation (5 bucks/sires and 10 daughters/bucks). A difference in longevity (+0.75 AI, i.e., 32 d) was observed between the 2 lines. In farm 1, the differences were mainly due to culling (26% in the LL line vs. 14% in the HL line) whereas mortality was similar in the 2 lines. In farm 2, mortality and culling were both higher in the LL line than in the HL line (33 vs. 15% and 19 vs. 7%, respectively). There was no difference between the 2 lines in terms of the reproduction traits recorded for each kindling. Nevertheless, because of the difference in the litter number between the 2 lines, the sum of young rabbits born alive per doe over her lifetime and the sum of young rabbits weaned per doe were higher in the HL line (+5 kits; P < 0.01). Selection for functional longevity using survival analysis is feasible for modifying lifetime reproduction traits.

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The sequence of the pig has now been published. Associated with genomic tools such as high density genotyping, (re)sequencing, comparative genetic, it offers new opportunity to understand the genetic basis of complex traits. The challenge is now to get adequate phenotypes. For minipigs, focus is made on traits relevant for medicine, in order to use minipigs as a biomedical model. Because of the number of research fields, specific lines had to be developed and within the last decades, several minipig lines were made available. For example, to specifically study development and regression of cutaneous melanoma, the MeLiM line was built up to largely express this particular trait. It was then possible to study the genetic determinism of this trait and acquire knowledge relevant for human disease, and in a lesser extent also relevant for pig production. Currently, one of our aims is to develop a minipig line adequate for studies on human nutrition related diseases, such as obesity or atherosclerosis. This approach first requires the characterization of minipigs to understand the genetic determinism of their behavior but also some physiological parameters related to human nutrition.

The study was based on performance recording (with 23 meat quality traits) in progenytesting station of half-sib families composed of 50 offspring (castrates and females) frompurebred sires. The aim of this scheme was to estimate, in French purebred pig populations,the effect of polymorphisms. Data will be presented for 1,740 genotyped animals belonging to4 groups of breeds: LW (3 Large-White type populations), LF (French Landrace), D (3 Durocpopulations) and CH (4 Chinese-European lines). Eight polymorphisms in RN (PRKAG3)gene were analyzed: R200Q, V199I, G52S, K131R, P134L, T30N, V41I, L53P. Nopolymorphism was found for R200Q and L53P. Six haplotypes were defined with theremaining mutations. Effect of haplotypes was estimated with MIXED procedure (SASsoftware) with sex and slaughter date as fixed effects, mother and father as random effects andcarcass weight as covariate. Most significant results were observed for pHSM(semimembraneouspH 24 h post mortem) and MQI (Meat Quality Index combining pHSM,Minolta L* and water holding capacity both on gluteus superficialis) in LW, LF, and D, fordrip loss in LW and LF and for color traits (Minolta L*, a*, b*) in LW, LF and CH. Resultswill be illustrated focusing on 2 meat quality traits (MQI, and drip loss) and 2 haplotypes.Haplotypic frequencies estimated on parents are 26% and 10% in LW, 64% and 20% in LF,40% and 47% in D and 12% and 21% in CH for haplotype 1 and 2 respectively. Haplotype 1is favorable for the 2 considered traits. Regarding combinations of haplotypes, 11 issignificantly better than 16 in LW, LF and D and even more than 66 in D. Estimated effectsbetween 11 and 16 are between 0.2 and 0.8 phenotypic standard deviation; the highest beingobserved in LW. In D, differences between 11 and 66 animals are estimated to be 0.9phenotypic standard deviation for MQI.

The European pig industry is engaged in a voluntary abandonment of surgical castration ofmale piglets by 2018. A condition of this abandonment is to solve different problems relatedto breeding boars, especially meat quality. One of the best ways is that of genetics, includinggenomic selection. A resource population has been implemented using French Pietrain pigsraised in a control animal testing station. About 1500 Pietrain type or cross-type Pietrain ×Large White boars were raised and slaughtered to determine the characteristics of sexualdevelopment, body composition and above all meat quality traits. Plasma testosteroneconcentration differed from one genetic type to another, but the differences were generallysmall. This concentration was not affected by the batch or by the weight of the animals or bytheir age at measurement. Androstenone content in backfat was not affected by the batch butthe average almost doubled from one genetic type to another, the highest levels beingobserved both in one Pietrain type and in one crossbred type. Androstenone content increasedwith slaughter weight and plasma testosterone concentration. The effect of slaughter agedepended on the genetic type. Skatole content in backfat was little affected by theconcentration of testosterone, but varied from one batch to another, from one genetic type toanother and decreased with age at slaughter. Genetic parameters were estimated in thedifferent populations. They were estimated within the range of values usually observed forthese traits.

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Chantier qualité GA; Improvement of feed efficiency can be achieved by genetic selection directly on feed to BW gain ratio or for alternative traits. In the present study, 2 different traits were explored in the growing rabbit and their heritability and genetic correlations with traits recorded between weaning (30 d) and 63 d of age: i) residual feed intake (RFI), to select animals having low ad libitum feed intake independently from their production level, and ii) ADG under restricted feeding (ADGR; with a restriction level of 80% compared with ad libitum feeding of a control group), to select animals having high growth rate despite limited feed intake. To study these traits, 2 rabbit lines were established named i) ConsoResidual line and ii) ADGrestrict line. Under ad libitum or restricted feeding, it comes to select animals that waste less energy for maintenance, metabolism, or activity and retain more for tissue deposition. The selection process was similar in both lines. Data comprised records from generations 0 to 6 for about 1,800 rabbits per line measured for their BW at weaning and 63 d of age (BW63) and their individual feed consumption. Under ad libitum feeding, the heritability estimates were moderate for RFI (0.16 ± 0.05), ADG (0.19 ± 0.05), and feed conversion ratio (FCR; 0.22 ± 0.05). The high genetic correlation estimated between RFI and FCR (0.96 ± 0.03) was in accordance with the literature. The genetic correlation between RFI and ADG traits was not significant. Thus, selection for low RFI with ad libitum feeding was confirmed as a potential trait to improve FCR and reduce feed intake, with little effect on ADG. To our knowledge, there is no previous selection experiment on growing rabbits with restricted feeding. Our heritability estimates for ADGR and feed conversion ratio under restricted feeding (FCRR) were moderate (0.22 ± 0.06 and 0.23 ± 0.07, respectively) and had very high negative genetic correlation. Both selection criteria were found with high and favorable genetic correlations with feed efficiency recorded under each feeding regimen. However, their different genetic correlations with BW at weaning and at 63 d of age (BW63R; respectively, 0.85 and 0.17 for RFI and -0.25 and 0.81 for ADGR) suggested different impacts on major production traits that need further analyses to decipher the relative advantages of the 2 selection criteria, together with interactions between genotypes and feeding regimen.

Les filières porcines européennes se sont engagées dans une démarche volontaire d’abandon de la castration chirurgicale des porcelets d’ici 2018. Les mâles entiers étant plus agressifs que les mâles castrés, il est particulièrement important de prendre en compte leur comportement dans la sélection génétique. L’agressivité des porcs peut être estimée à partir du nombre de lésions corporelles. Ce travail rapporte le dénombrement des lésions de porcs mâles entiers, élevés en station de testage, à deux stades au cours de la croissance (2 jours après transfert dans le bâtiment d’engraissement puis avant les premiers départs à l’abattoir) et sur les carcasses. Trois populations de verrats à composante principale Piétrain (PP) ont été utilisées pour produire ces porcs par croisement avec des truies PP ou des truies à composante principale Large White. Environ 900 mâles, répartis sur cinq bandes, ont été suivis. Le nombre total de lésions, très élevé après le transfert des animaux, diminue en fin d’engraissement (P < 0,001). Les nombres de lésions situées de chaque côté sont liés (r varie de 0,64 à 0,81, P < 0,001) quel que soit le stade mais chez certains animaux les nombres peuvent aller du simple au double si bien que la mesure de chaque côté est nécessaire pour une évaluation individuelle précise. Les corrélations entre stades sont relativement faibles bien que significatives (r varie de 0,07 à 0,30, P < 0,05). Des différences très importantes existent entre les types génétiques de porcs qui sont retrouvées quel que soit le stade de mesure (P < 0,001). Globalement, les lésions sont moins nombreuses chez les porcs de type Piétrain que chez ceux de type génétique croisé., The European pig industry is engaged in a voluntary abandonment of surgical castration of piglets by 2018. Entire males being more aggressive than castrated males, it is very important to take into account their behaviour for genetic selection in order to avoid problems linked to aggressiveness. Aggressiveness of pigs can be estimated from the number of skin lesions. Present work describes the number of skin lesions measured at two stages during fattening (2 days after transfer to the fattening unit, shortly before first pigs are sent to the slaughterhouse) as well as on carcasses. Three populations of Pietrain (PP) type boars were used to produce the males for the present experiment using PP or LW dams. About 900 males, from five replicates, were followed. The total number of skin lesions was very high after transfer to the fattening unit and decreased at the end of fattening (P < 0.001). Total numbers of skin lesions located on both sides of the pigs were linked (r ranged from 0.64 to 0.81, P < 0.001) regardless of the stage, but in some animals, lesions on one side could be twice the number of those on the other side. This made measurements on both sides necessary for a precise evaluation at individual level. Correlations between stages were relatively low even though significant (r ranged from 0.07 to 0.30, P < 0.05). Significant differences existed between genetic types of pigs that were present at the three stages (P < 0.001). Overall, skin lesions were less numerous in pigs of the Pietrain type than in cross‐bred pigs.