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Use of mate allocation in pig crossbreeding schemes: a simulation study

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González-Diéguez D et al., 70th Annual meeting of the European Federation of Animal science (EAAP), 26-30 août 2019, Ghent, Belgique, p. 287

One of the main goals in a crossbreeding scheme is to improve the performance of crossbred population by exploiting heterosis and breed complementarity. Dominance is one of the likely genetic bases of heterosis and, nowadays, estimating dominance effects in genetic evaluations has become feasible in a genomic selection context. Mate allocation strategies that account for inbreeding and/or dominance can be of interest for maximizing the crossbred performance. The objective of this study was to simulate scenarios including or not mate allocation strategies in two-breed pig crossbreeding schemes. The different crossbreeding scenarios have been compared in terms of genetic gain (within-breed) and total genetic value in crossbred populations. The benchmark scenario is a crossbreeding scheme where within-line selection is performed on purebred genomic estimated breeding values and crossbreds come from random matings of the best purebreds. The other subsequent scenarios are conceived to evaluate the potential benefits of accounting for inbreeding, dominance and crossbred performances in the genetic evaluation model. Genomic mate allocation is a promising strategy to improve the crossbred performance.

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2019

Relationship between sperm production and boar taint risk of purebred or crossbred entire offspring

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Marie-José Mercat et al., 66th EAAP, Varsovie, Pologne, 31 aout-4 septembre 2015, visuels d'intervention

This study focuses on 100 boars from three Pietrain varieties: 74 V1, 10 V2 and 16 V3. On average, data were recorded on 90 ejaculates collected in artificial insemination centers and boar taint measured on 15.4 entire male 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 in fat collected at the slaughterhouse. Sperm production data were corrected for the production site, the age and the collection frequency using a generalized linear mixed model to estimate an average sperm production count per boar and ejaculate. Boar taint odor risk was on the whole low in the tested population. Considering the three Pietrain varieties altogether, boars with the highest sperm production had a lower proportion of offspring without risk of odor compared to boars with low sperm production: the boars ranked in the top quartile of sperm production had 14% less offspring without odor (i.e. androstenone <1.0 &•6;g/g and skatole <0.2 &•6;g/g) compared to the boars in the bottom quartile (P<0.05). The sperm production of the sires of pigs with high androstenone content in fat was on average higher than that of the sires of pigs with low androstenone content: 95.3 and 86.8 billion spermatozoa per ejaculate for the sires of offspring with more than 3.0 &•6;g/g of androstenone and non-detectable androstenone level, respectively (P<0.05). Differences were more pronounced on crossbred offspring than on purebred ones. With V1 sires alone, differences were smaller but still significant. As a conclusion, selection against boar taint might negatively impact semen production if reproduction traits are not included in the breeding goal.

PDF icon Marie-José Mercat et al., 66th EAAP, Varsovie, Pologne, 31 aout-4 septembre 2015
2017

Exploring transcriptomic diversity in muscle revealed that cellular signaling pathways mainly differentiate five Western porcine breeds

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Background

Among transcriptomic studies, those comparing species or populations can increase our understanding of the impact of the evolutionary forces on the differentiation of populations. A particular situation is the one of short evolution time with breeds of a domesticated species that underwent strong selective pressures. In this study, the gene expression diversity across five pig breeds has been explored in muscle. Samples came from: 24 Duroc, 33 Landrace, 41 Large White dam line, 10 Large White sire line and 39 Piétrain. From these animals, 147 muscle samples obtained at slaughter were analyzed using the porcine Agilent 44 K v1 microarray.

Results

A total of 12,358 genes were identified as expressed in muscle after normalization and 1,703 genes were declared differential for at least one breed (FDR < 0.001). The functional analysis highlighted that gene expression diversity is mainly linked to cellular signaling pathways such as the PI3K (phosphoinositide 3-kinase) pathway. The PI3K pathway is known to be involved in the control of development of the skeletal muscle mass by affecting extracellular matrix - receptor interactions, regulation of actin cytoskeleton pathways and some metabolic functions. This study also highlighted 228 spots (171 unique genes) that differentiate the breeds from each other. A common subgroup of 15 genes selected by three statistical methods was able to differentiate Duroc, Large White and Piétrain breeds.

Conclusions

This study on transcriptomic differentiation across Western pig breeds highlighted a global picture: mainly signaling pathways were affected. This result is consistent with the selection objective of increasing muscle mass. These transcriptional changes may indicate selection pressure or simply breed differences which may be driven by human selection. Further work aiming at comparing genetic and transcriptomic diversities would further increase our understanding of the consequences of human impact on livestock species.

2015
La race cul noir du Limousin

Les races porcines locales françaises (à petits effectifs et en conservation)

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Des fiches pour mieux connaitre les races locales porcines française, à petits effectifs et en conservation.

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2014