Publications 2020

In mammalian ovaries, the theca layers of growing follicles are critical for maintaining their structural integrity and supporting androgen synthesis. Through combining the postnatal monitoring of ovaries by abdominal magnetic resonance imaging, endocrine profiling, hormonal analysis of the follicular fluid of growing follicles, and transcriptomic analysis of follicular theca cells, we provide evidence that the exposure of ovine fetuses to testosterone excess activates postnatal follicular growth and strongly affects the functions of follicular theca in adulthood. Prenatal exposure to testosterone impaired androgen synthesis in the small antral follicles of adults and affected the expression in their theca cells of a wide array of genes encoding extracellular matrix components, their membrane receptors, and signaling pathways. Most expression changes were uncorrelated with the concentrations of gonadotropins, steroids, and anti-Müllerian hormone in the recent hormonal environment of theca cells, suggesting that these changes rather result from the long-term developmental effects of testosterone on theca cell precursors in fetal ovaries. Disruptions of the extracellular matrix structure and signaling in the follicular theca and ovarian cortex can explain the acceleration of follicle growth through altering the stiffness of ovarian tissue. We propose that these mechanisms participate in the etiology of the polycystic ovarian syndrome, a major reproductive pathology in woman.

Le phosphore en agriculture constitue à la fois une ressource limitée et une source potentielle de pollution lorsqu'il est utilisé en excès comme fertilisant. Les systèmes d'élevages jouent un rôle particulièrement important dans les flux de phosphore, les déjections animales contribuant à l'échelle nationale à près de la moitié des apports sur les sols, avec une forte variabilité selon les régions. Les produits animaux contribuent aussi largement à la couverture des besoins pour l'alimentation humaine en apportant près de 60% du phosphore total de la ration moyenne des Français. L'efficacité de rétention du phosphore par les animaux est très variable selon les espèces. La plus élevée est obtenue chez le poulet standard, suivi du porc, du poulet label rouge et de la vache laitière, les poules pondeuses et les vaches allaitantes présentant des efficacités plus faibles. Toutefois, à l'échelle du système de production, les pressions en phosphore organique sont plus faibles pour les élevages de ruminants qui disposent de plus de surface d'épandage. Ces dernières années l'amélioration des connaissances des besoins et de l'utilisation digestive du phosphore ont permis de réduire fortement les apports en phosphore et les rejets, avec pour les animaux monogastriques l'effet additionnel de l'utilisation de phytases. Les pertes de phosphore vers l'environnement étant limitées, comparativement aux pertes d'azote, il est théoriquement possible d'atteindre des valeurs très élevées d'efficacité d'utilisation du phosphore dans les systèmes agricoles, mais ceci nécessite un parfait recyclage du phosphore des déjections animales et de celui des coproduits animaux.

David, S.-A. ; Vitorino Carvalho, A. ; Gimonnet, C. ; Brionne, A. ; Hennequet-Antier, C. ; Piégu, B. ; Crochet, S. ; Couroussé, N. ; Bordeau, T. ; Bigot, Y. ; Collin, A. ; COUSTHAM, V.Frontiers in Genetics, 2019, 10 : 11 p. Article

Belloir, P. ; Lessire, M. ; Lambert, W. ; Corrent ; Berri, C. ; Tesseraud, S.animal, 2019, 13 (05) : 1094-1102. Article

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Background: In pig production systems, weaning is a crucial period characterized by nutritional, environmental, and social stresses. Piglets transition from a milk-based diet to a solid, more complex plant-based diet, and their gut physiology must adapt accordingly. It is well established that piglets weaned later display improved health, better wean-to-finish growth performance, and lower mortality rates. The aim of this study was to evaluate the impact of weaning age on fecal microbiota diversity and composition in piglets. Forty-eight Large White piglets were divided into 4 groups of 12 animals that were weaned at different ages: 14 days (early weaning), 21 days (a common weaning age in intensive pig farming), 28 days (idem), and 42 days (late weaning). Microbiota composition was assessed in each group by sequencing the 16S rRNA gene using fecal samples taken on the day of weaning, 7 days later, and at 60 days of age. Results: In each group, there were significant differences in fecal microbiota composition before and after weaning (p < 0.05), confirming that weaning can drastically change the gut microbiota. Microbiota diversity was positively correlated with weaning ag e: microbial alpha diversity and richness were higher in piglets weaned at 42 days of age both on the day of weaning and 7 days later. The abundance of Faecalibacterium prausnitzii operational taxonomic units (OTUs) was also higher in piglets weaned at 42 days of age. Conclusions: Overall, these results show that late weaning increased gut microbiota diversity and the abundance of F. prausnitzii, a microorganism with positive effects in humans. Piglets might thus derive a competitive advantage from later weaning because they have more time to accumulate a higher diversity of potentially beneficial microbes prior to the stressful and risky weaning period.

This study assessed the transfer of fumonisins B1 and B2 (FBs), zearalenone (ZEA) and zearalenone metabolites alpha-zearalanol (alpha-ZAL) and alpha-zearalenol (alpha-ZEL) to poultry tissues. Two experimental groups of 9 male chickens each were exposed for 8 weeks to a contaminated diet (FB group: 12.7 mg FB1 + FB2 kg(-1), ZEA group: 0.40 mg ZEA kg(-1)). To measure the carry-over from feed to animal tissues (liver and muscle), a sensitive and accurate SIDA-UHPLC-MS/MS method was developed and validated. For all mycotoxins, the limit of detection (LOD) was 0.3 mu g kg(-1) and the limit of quantification (LOQ) was 1.0 mu g kg(-1). Recoveries ranged from 92% to 107% and the intermediate precision coefficients of variation (CVIP) were between 4.3% and 13%. ZEA and alpha-ZAL were not detected in livers, whereas alpha-ZEL was detected in five out of eight samples at levels between LOD and LOQ. FBs were detected and quantified in the livers of all animals exposed to the contaminated diet (mean 30.3 mu g FB1 kg(-1) and 2.3 mu g FB2 kg(-1)). A significant correlation between the FB1 and the FB2 contents in the liver was demonstrated and FB carry-over factors (CFs) from feed to liver were determined (CFFB1: 0.003 and CFFB2: 0.001). Filet muscles from the same animals were also analysed. FB1 was quantified at trace levels in eight samples out of nine (mean 2.0 mu g kg(-1)) and was only detected in the remaining sample. FB2 was detected in only one muscle sample.

The alpha-1 isoform of chicken AMPK situates on the Z-chromosome, in contrast, the other isoforms in birds and the mammalian AMPK alpha 1 are located on the autosomes. The present study aimed to investigate the role of hepatic AMPK signaling in adaptation to nutritional status and the potential sex-specific response in chickens. Hepatic genes and proteins were compared between the two sexes immediately after hatching. From 20d of age, chicks from each sex received feed treatments: Control was fed ad libitum; Fasted was starved for 24 h; Refed was fed for 4 h after a 24 h fasting. As a result, hepatic AMPK alpha 1 mRNA level in males was significantly higher at both ages compared to females, due to the presence of Z-chromosomes. However, this did not make this kinase "malebias" as it was eventually compensated at a translational level, which was not reported in previous studies. The protein levels and activation of AMPK alpha were even lower in newly-hatched male compared to female chicks, accompanied with a higher FAS and SREBP-1 gene expressions. Accordingly, hepatic G6PC2 mRNA levels in males were significantly lower associated with lower plasma glucose levels after hatching. Fasting activated hepatic AMPK, which in turn inhibited gene expression of GS, FAS and SREBP-1, and stimulated the downstream G6PC2 in both sexes. These changes recovered after refeeding. In conclusion, AMPK plays a role in adaptation to nutritional environment for both sexes. The Z-linked AMPK did not exert a sex-specific signaling, due to a "translational compensation" of AMPK alpha 1.

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