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

Diversity across major and candidate genes in European local pig breeds

The aim of this work was to analyse the distribution of causal and candidate mutations associated to relevant productive traits in twenty local European pig breeds. Also, the potential of the SNP panel employed for elucidating the genetic structure and relationships among breeds was evaluated. Most relevant genes and mutations associated with pig morphological, productive, meat quality, reproductive and disease resistance traits were prioritized and analyzed in a maximum of 47 blood samples from each of the breeds (Alentejana, Apulo-Calabrese, Basque, Bísara, Majorcan Black, Black Slavonian (Crna slavonska), Casertana, Cinta Senese, Gascon, Iberian, Krskopolje (Krskopoljski), Lithuanian indigenous wattle, Lithuanian White Old Type, Mora Romagnola, Moravka, Nero Siciliano, Sarda, Schwa-bisch-Hallisches Schwein (Swabian Hall pig), Swallow-Bellied Mangalitsa and Turopolje). We successfully analyzed allelic variation in 39 polymorphisms, located in 33 candidate genes. Results provide relevant information regarding genetic diversity and segregation of SNPs associated to production and quality traits. Coat color and morphological trait-genes that show low level of segregation, and fixed SNPs may be useful for traceability. On the other hand, we detected SNPs which may be useful for association studies as well as breeding programs. For instance, we observed predominance of alleles that might be unfavorable for disease resistance and boar taint in most breeds and segregation of many alleles involved in meat quality, fatness and growth traits. Overall, these findings provide a detailed catalogue of segregating candidate SNPs in 20 European local pig breeds that may be useful for traceability purposes, for association studies and for breeding schemes. Population genetic analyses based on these candidate genes are able to uncover some clues regarding the hidden genetic substructure of these populations, as the extreme genetic closeness between Iberian and Alentejana breeds and an uneven admixture of the breeds studied. The results are in agreement with available knowledge regarding breed history and management, although largest panels of neutral markers should be employed to get a deeper understanding of the population’s structure and relationships

Influences génétiques sur les processus d'adaptation et le comportement alimentaire chez le porc

National audienceAdaptation to environmental challenges involves behavioural and neuroendocrine mechanisms, with specific components such as feeding, sexual and social behaviours, and more general processes known as emotional or stress responses. Every such mechanism has been shown to be influenced by genetic factors, most often with a polygenic inheritance, with the noticeable exception of the porcine stress syndrome that follows a monogenic autosomal recessive inheritance. Numerous papers document the differences between breeds in general behavioural reactivity, social and feeding behaviours, and adrenocortical aids function. Some information about heritability is also available. Finally, more recent approaches using molecular genetics, allow the exploration of molecular mechanisms underlying the genetic influences. These approaches led to the identification of a mutation in the ryanodyne receptor gene, responsible for the porcine stress syndrome. In the near future, QTL studies may provide molecular markers linked to adaptation traits, for animal selection.Pour répondre aux stimulations provoquées par son environnement, l’animal sollicite en permanence ses capacités adaptatives, dans ses composantes comportementales et biologiques. On peut distinguer des aspects spécifiques (comportements alimentaires, sexuels, sociaux par exemple) et des aspects plus généraux regroupés sous le terme de réponses émotionnelles ou stress. Tous ces mécanismes sont influencés par des facteurs génétiques, le plus souvent de nature polygénique, à l’exception notable du syndrome de stress aigu du porc qui résulte d’une mutation autosomale récessive. De nombreuses études mettent en évidence des différences entre races : elles concernent la réactivité comportementale, les interactions sociales, la réponse de l’axe corticotrope au stress, ou encore le comportement alimentaire. Ces études intègrent parfois l’estimation des paramètres génétiques et notamment l’héritabilité de ces caractères. Enfin, les méthodes de génétique moléculaire permettent l’exploration fine des mécanismes de ces influences génétiques. Ainsi, le gène du récepteur à la ryanodine a -t-il été identifié pour son implication dans le syndrome de stress aigu du porc. L’utilisation de marqueurs moléculaires pour la sélection des animaux présente également des perspectives prometteuses, comme le montrent les recherches de locus à effets quantitatifs (QTL) pour les caractères en rapport avec les processus d’adaptation

Changes in sow of the electrical conductivity of vaginal mucus in different reproductive situations.

International audienc

Genetic determinism of boar taint and relationship with meat traits

International audienceEntire male meat can have a major quality defect called boar taint, partly due to the presence of androstenone in fat. This study evaluates the feasibility of a selection to directly decrease back fat androstenone level or indirectly by a selection on the plasma estradiol level and estimate the consequences on meat traits in purebred or crossbred pigs. Pure Pietrain (P) and Pietrain Large White crossbred pigs (X) were measured for hormone levels: estradiol (Est) and testosterone (Tes), growth traits: average daily gain, feed conversion ratio (FCR), average daily feed intake (ADFI), carcass composition: carcass yield (CY), lean percentage (L%) and quality traits: pH in Ld and ham, drip loss, intramuscular fat and back fat androstenone level (Andr). The number of skin lesions (SL) was measured at three stages. Carcass additional measures were obtained by computerized tomography: loin eye area (LEA) and density, femur density, ham muscle/bone length ratio (HFR). The number of measured animals varied from 553 to 712 for P and from 556 to 736 and for X. Heritabilities were of medium values for estradiol level and high values for androstenone level. A selection to decrease P Andr level would increase HFR and pH in ham and decrease FCR and Tes in P pigs. On X it would increase CY, LEA, L% and HFR and decrease SL at fattening entrance, FCR, drip loss, ADFI and femur density. A selection to decrease P Est level would decrease Andr, FCR, ADFI and Tes in P pigs and Andr, SL at fattening entrance and Tes in X pigs. Heritabilities and genetic correlations indicate that a selection to decrease estradiol level would have overall favourable effects on meat trait

Dosage haut débit des lipides intramusculaires de la viande de porc par imagerie par résonance magnétique

International audienceIn all animal species, the amount of fat and its distribution within body compartments determine both the productive efficiency and quality of meat, including sensory acceptability and potential benefits for human nutrition. Among the characteristics of the pig muscle that predict these qualities, the level of intramuscular fat (IMF) is the most commonly used because of its high heritability and its strong mean genetic correlation with overall acceptability of the meat. For example, the specifications for fresh meat under the French “Label Rouge” set the desirable level of IMF at 3% in the loin. The determination of intramuscular fat is based on meticulous and time-consuming standard chemical extraction methods. In this work, we validated a reliable and accurate magnetic resonance imaging (MRI) method to determine IMF content and distribution in intact pig muscle samples using very limited sample preparation and image analysis by comparison with a standard chemical extraction method and two physical methods, the near infrared transmittance and a self-calibrated nuclear magnetic resonance NMR relaxometry. IMF values obtained through MRI matched well with those obtained by the NMR technique with a standard error of calibration of 0.18% and by the Soxhlet extraction technique and the NIT technique, with an identical standard error of calibration of 0.25%. This high throughput MRI method is able to scan 24 samples simultaneously and to determine the IMF content of more than 500 samples per day

Recherche et identification de gènes différentiellement exprimés dans l'épididyme de verrat par une approche transcriptomique

National audienc

Etude des moments d'ovulation et d'insémination chez la truie et de leurs conséquences sur la taille de la portée en élevages

National audienc

Analyse transcriptomique des gènes exprimés de façon différentielle dans l'épididyme de verrat

National audienc

Le transcriptome épididymaire du verrat : étude de la régionalisation

National audienc