Sélectionner sur l'adiposité pour améliorer la qualité

Sélectionner sur l'adiposité pour améliorer la qualit

The adult boar testicular and epididymal transcriptomes

<p>Abstract</p> <p>Background</p> <p>Mammalians gamete production takes place in the testis but when they exit this organ, although spermatozoa have acquired a specialized and distinct morphology, they are immotile and infertile. It is only after their travel in the epididymis that sperm gain their motility and fertility. Epididymis is a crescent shaped organ adjacent to the testis that can be divided in three gross morphological regions, head (caput), body (corpus) and tail (cauda). It contains a long and unique convoluted tubule connected to the testis via the efferent ducts and finished by joining the <it>vas deferens </it>in its caudal part.</p> <p>Results</p> <p>In this study, the testis, the efferent ducts (<it>vas efferens</it>, VE), nine distinct successive epididymal segments and the deferent duct (<it>vas deferens</it>, VD) of four adult boars of known fertility were isolated and their mRNA extracted. The gene expression of each of these samples was analyzed using a pig generic 9 K nylon microarray (AGENAE program; GEO accession number: GPL3729) spotted with 8931 clones derived from normalized cDNA banks from different pig tissues including testis and epididymis. Differentially expressed transcripts were obtained with moderated t-tests and F-tests and two data clustering algorithms based either on partitioning around medoid (top down PAM) or hierarchical clustering (bottom up HCL) were combined for class discovery and gene expression analysis. Tissue clustering defined seven transcriptomic units: testis, <it>vas efferens </it>and five epididymal transcriptomic units. Meanwhile transcripts formed only four clusters related to the tissues. We have then used a specific statistical method to sort out genes specifically over-expressed (markers) in testis, VE or in each of the five transcriptomic units of the epididymis (including VD). The specific regional expression of some of these genes was further validated by PCR and Q-PCR. We also searched for specific pathways and functions using available gene ontology information.</p> <p>Conclusion</p> <p>This study described for the first time the complete transcriptomes of the testis, the epididymis, the <it>vas efferens </it>and the <it>vas deferens </it>on the same species. It described new genes or genes not yet reported over-expressed in these boar tissues, as well as new control mechanisms. It emphasizes and fulfilled the gap between studies done in rodents and human, and provides tools that will be useful for further studies on the biochemical processes responsible for the formation and maintain of the epididymal regionalization and the development of a fertile spermatozoa.</p

Adiposité et génétique chez le porc : état des lieux et nouveaux enjeux pour la qualité des produits

Carcass adiposity of pigs slaughtered in France has decreased by 45% on average between 1977 and 2016. The production of increasingly lean animals has been initiated in the 1950-1960’s by setting up commercial grading scales for carcasses and differentiated payment according to their lean content, to the detriment of fatty tissues. This evolution led to a standardization of production, leading to difficulties in meeting the quality demand of certain market segments. However, a renewed interest for fat has occurred recently within the French pork industry. Indeed, fatty tissues have many advantages, both for ability for processing into cured products and delicatessen, as for sensory and nutritional qualities of products. This review provides an update on pig genetics’ improvement in France in relation to adiposity and product quality. After a reminder of the characteristics of fat tissues and their importance for the quality of meat and pork products, the factors influencing adiposity and the traits related to fat quantity taken into account in breeding programs are presented. An inventory of the genetic variability of fatness that remains within French pig populations (selected and local breeds) is drawn up. This will allow defining future selection strategies, to better meet the various expectations of pork industry and consumer

Adiposité et amélioration génétique chez le porc : état des lieux et nouveaux enjeux pour la qualité des produits

The adiposity of carcasses of pigs slaughtered in France decreased by 45% on average from 1977 to 2016. This is the result of 40 years of production of increasingly lean animals, initiated from 1950-1960 by setting up commercial grading scales for carcasses and differentiated payment according to lean tissue content, to the detriment of fatty tissues. This evolution led to standardization of production, leading to difficulties in meeting the demand of certain market segments. However, changes have occurred in recent years within the French pork industry, resulting in a renewed interest in fat and the desire to move towards greater diversification of produced and marketed carcasses. Indeed, adipose tissues have many advantages, both for the processing of cured meat products and delicatessen products (fat cover), as well as for sensory and nutritional qualities of products (intramuscular lipids).This review provides an update on pig genetic improvement in France in relation to adiposity and product quality. After a reminder of the importance of adipose tissues for meat quality and the characteristics of these tissues, factors of variation of adiposity and traits related to the amount of fat considered in breeding programs (measurement methods, genetic parameters) are presented. An inventory of the genetic variability that remains within French pig populations (selected breeds and local breeds) in terms of quantity and distribution of adipose tissues is drawn up. This assessment is necessary to define future selection strategies in order to better meet the various expectations of the pork industry and consumers.L’adiposité des carcasses de porcs abattus en France s’est réduite en moyenne de 45% entre 1977 et 2016. Ce constat est le résultat de 40 années de production d’animaux de plus en plus maigres, initiée dans les années 1950-1960 par la mise en place des grilles de classement commercial des carcasses et de paiement différencié en fonction de leur teneur en tissus maigres, au détriment des tissus gras. Cette évolution a conduit à une standardisation de la production, entraînant des difficultés pour répondre à la demande de certains segments de marché. Toutefois, une nouvelle évolution s’opère depuis quelques années au sein de la filière porcine française, se traduisant par un regain d’intérêt pour le gras et la volonté de s’orienter vers une plus grande diversification des carcasses produites et commercialisées. En effet, les tissus adipeux présentent de nombreux atouts, tant pour la transformation en produits de charcuterie et salaison (gras de couverture), que pour les qualités sensorielles et nutritionnelles des produits (lipides intramusculaires).Cette synthèse fait le point sur les évolutions de l’amélioration génétique du porc en France en lien avec l’adiposité et la qualité des produits. Après un rappel sur l’intérêt des tissus adipeux pour les qualités des viandes et sur les caractéristiques de ces tissus, les facteurs de variation de l’adiposité et les caractères de quantité de gras pris en compte dans les programmes d’amélioration génétique (méthodes de mesure, paramètres génétiques) sont présentés. Un état des lieux de la variabilité génétique qui demeure au sein des populations porcines françaises (races sélectionnées et races locales) en termes de quantité et de répartition des tissus adipeux est dressé. Ce bilan est nécessaire pour définir les futures stratégies de sélection, afin de mieux répondre aux diverses attentes des industriels et des consommateurs

Paramètres génétiques des principales anomalies congénitales porcines

Mention d'édition : Journées Recherche PorcineNational audienc

Elongated unique DNA strand deposition on microstructured substrate by receding meniscus assembly and capillary force

International audienceOrdered deposition of elongated DNA molecules was achieved by the forced dewetting of a DNA solution droplet over a microstructured substrate. This technique allows trapping, uncoiling, and deposition of DNA fragments without the need of a physicochemical anchoring of the molecule and results in the combing of double stranded DNA from the edge of microwells on a polydimethylsiloxane (PDMS) substrate. The technique involves scanning a droplet of DNA solution caught between a movable blade and a PDMS substrate containing an array of microwells. The deposition and elongation appears when the receding meniscus dewets microwells, the latter acting here as a perturbation in the dewetting line forcing the water film to break locally. Thus, DNA molecules can be deposited in an ordered manner and elongated conformation based solely on a physical phenomenon, allowing uncoiled DNA molecules to be observed in all their length. However, the exact mechanism that governs the deposition of DNA strands is not well understood. This paper is an analysis of the physical phenomenon occurring in the deposition process and is based on observations made with the use of high frame/second rate video microscop

Approche transcriptomique de l’acquisition de la fertilité du spermatozoïde chez le verrat

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Le transcriptome épididymaire du verrat : étude de la régionalisation

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Analyse du transcriptome épididymaire chez le verrat

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Estimation, dans un dispositif familial issu des populations porcines françaises en sélection, de l’effet quantitatif de mutations dans des gènes majeurs et des gènes candidats

The study was based on performance recording (for growth, carcass composition and meat quality traits) in progeny testing station of half‐sib families composed of 50 offspring (castrates and females) from pure‐bred sires. The aim of this scheme was to estimate, in French purebred pig populations, the effect of mutations described in the literature, some of which are commercially exploited. [br/] The study focused on 55 families of European breeds and Chinese‐European or synthetic lines and on 17 polymorphisms located in HAL (1 SNP), IGF2 (1 SNP), MC4R (1 SNP), RN (8 SNP), H‐FABP (3 SNP) and CBG (3 SNP) genes.[br/] In all, 2569 animals were genotyped. Allelic frequencies of the mentioned mutations were estimated such as the effects associated with these polymorphisms in French pure‐bred populations on about forty traits. [br/] Significant effects were observed for each SNP, the most important (regarding numbers and significance levels) being for HAL and IGF2 genes. These results show that the scheme is well suited to underscoring strong effects. Results are less significant for the other tested markers showing a limited power of the scheme such as the probable non‐causality of part of these polymorphisms. However, results obtained with MC4R and RN_V199I noted rn* mutations are in agreement with those described in the literature.L’étude repose sur le contrôle de performances en station (croissance, composition corporelle et qualité de viande) de familles composées d’une cinquantaine de descendants (mâles castrés et femelles) d’un même père de race pure. Ce dispositif a vocation à estimer, dans les populations porcines françaises en sélection, l’effet de mutations publiées dans la bibliographie, certaines parfois exploitées commercialement. L’étude porte sur 55 familles de races européennes, lignées sino‐européennes ou synthétiques et sur 17 polymorphismes présents dans les gènes HAL (1 SNP), IGF2 (1 SNP), MC4R (1 SNP), RN (8 SNP), H‐FABP (3 SNP) et CBG (3 SNP). [br/] Au total, 2569 animaux ont été génotypés. Les résultats de génotypage obtenus ont permis d’estimer les fréquences alléliques des mutations mentionnées ainsi que les effets associés à ces polymorphismes, dans les populations françaises en sélection et sur une quarantaine de caractères. Des effets significatifs ont été observés pour tous les SNP étudiés, les plus importants (en nombre et en significativité) étant pour les gènes HAL et IGF2. Ces résultats montrent que le dispositif est adapté à la mise en évidence d’effets forts. Les résultats sont moins significatifs pour les autres marqueurs testés traduisant d’une part, une puissance plus limitée du dispositif dans le cas d’effets plus modérés et, d’autre part, la non causalité probable d’une partie de ces polymorphismes. Cependant, les résultats observés pour les mutations MC4R et RN_V199I noté rn* vont globalement dans le même sens que ceux décrits dans la bibliographie