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Could Omega 3 Fatty Acids Preserve Muscle Health in Rheumatoid Arthritis?
No full textRheumatoid arthritis (RA) is a chronic inflammatory disease characterized by a high prevalence of death due to cardiometabolic diseases. As observed during the aging process, several comorbidities, such as cardiovascular disorders (CVD), insulin resistance, metabolic syndrome and sarcopenia, are frequently associated to RA. These abnormalities could be closely linked to alterations in lipid metabolism. Indeed, RA patients exhibit a lipid paradox, defined by reduced levels of total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol whereas the CVD risk is increased. Moreover, the accumulation of toxic lipid mediators (i.e., lipotoxicity) in skeletal muscles can induce mitochondrial dysfunctions and insulin resistance, which are both crucial determinants of CVD and sarcopenia. The prevention or reversion of these biological perturbations in RA patients could contribute to the maintenance of muscle health and thus be protective against the increased risk for cardiometabolic diseases, dysmobility and mortality. Yet, several studies have shown that omega 3 fatty acids (FA) could prevent the development of RA, improve muscle metabolism and limit muscle atrophy in obese and insulin-resistant subjects. Thereby, dietary supplementation with omega 3 FA should be a promising strategy to counteract muscle lipotoxicity and for the prevention of comorbidities in RA patients
Behavior of the Linear Regression method to estimate bias and accuracies with correct and incorrect genetic evaluation models
No full textBias in genetic evaluations has been a constant concern in animal genetics. The interest in this topic has increased in the last years, since many studies have detected overestimation (bias) in estimated breeding values (EBV). Detecting the existence of bias, arid the realized accuracy of predictions, is therefore of importance, yet this is difficult when studying small data sets or breeds. In this study, we tested by simulation the recently presented method Linear Regression (LR) for estimation of bias, slope, and accuracy of pedigree EBV. The LR method computes statistics by comparing EBV from a data set containing old, partial information with EBV front a data set containing all information (old and new, a whole data set) for the same individuals. The method proposes an estimator for bias ((Delta(p)) over cap), an estimator of slope ((b(p)) over cap), and 3 estimators related to accuracies: the ratio between accuracies ((p) over cap (omega,p)), the reliability of the partial data set [], and the ratio of reliabilities []. We simulated a dairy scheme for low (0.10) and moderate (0.30) heritabilities. In both cases, we checked the behavior of the estimators for 3 scenarios: (1) when the evaluation model is the same as the model used to simulate the data; (2) when the evaluation model uses an incorrect heritability; and (3) when the data includes an environmental trend. For scenarios in which the evaluation model was correct, the LR method was capable of correctly estimating bias, slope, and accuracies, with better performance for higher heritability [i.e., corr[b(p) ,(b) over cap (p)] was 0.45 for h(2) = 0.10 and 0.59 for h(2) = 0.30]. In cases of the use of incorrect heritabilities in the evaluation model, the bias was correctly estimated in direction but not in magnitude. In the same way, the magnitudes of bias and of slope were underestimated in scenarios with environmental trends in data, except for cases in which contemporary groups were random and greatly shrunken. In general, accuracies were well estimated in all scenarios. The LR method is capable of checking bias and accuracy in all cases, if the evaluation model is reasonably correct or robust, and its estimations are more precise with more information (e.g., high heritability). If the model uses an incorrect heritability or a hidden trend exists in the data, it is still possible to estimate the direction and existence of bias and slope but not always their magnitudes
Probiotic Propionibacterium freudenreichii requires SlpB protein to mitigate mucositis induced by chemotherapy
No full textPropionibacterium freudenreichii CIRM-BIA 129 (P. freudenreichii wild type, WT) is a probiotic bacterium, which exerts immunomodulatory effects. This strain possesses extractable surface proteins, including SlpB, which are involved in antiinflammatory effect and in adhesion to epithelial cells. We decided to investigate
the impact of slpB gene mutation on immunomodulation in vitro and in vivo. In an in vitro assay, P. freudenreichii WT reduced expression of IL-8 (p<0.0001) and TNF-α (p<0.0001) cytokines in LPS-stimulated HT-29 cells. P. freudenreichii ΔslpB, lacking the SlpB protein, failed to do so. Subsequently, both strains were investigated in vivo in a 5-FU-induced mucositis mice model. Mucositis is a common side effect of cytotoxic chemotherapy with 5-FU, characterized by mucosal injury, inflammation, diarrhea, and weight loss. The WT strain prevented weight loss, reduced inflammation and consequently histopathological scores. Furthermore, it regulated key markers,
including Claudin-1 (cld1, p<0.0005) and IL-17a (Il17a, p<0.0001) genes, as well as IL-12 (p<0.0001) and IL-1β (p<0.0429) cytokines levels. Mutant strain displayed opposite regulatory effect on cld1 expression and on IL-12 levels. This work emphasizes the importance of SlpB in P. freudenreichii ability to reduce mucositis
inflammation. It opens perspectives for the development of probiotic products to decrease side effects of chemotherapy using GRAS bacteria with immunomodulatory surface protein properties
A procedure to quantify the feed intake response of growing pigs to perturbations
No full textImproving robustness of farm animals is one of the goals in breeding programmes. However, robustness is a complex trait and not measurable directly. The objective of this study was to quantify and characterize (elements of) robustness in growing pigs. Robustness can be analysed by examining the animal’s response to perturbations. Although the origin of perturbations may not be known, their effect on animal performance can be observed, for example, through changes in voluntary feed intake. A generic model and data analysis procedure was developed (1) to estimate the target trajectory of feed intake, which is the amount of feed that a pig desires to eat when it is not facing any perturbations; (2) to detect potential perturbations, which are deviations
of feed intake from the estimated target trajectory; and (3) to characterize and quantify the response of the growing pigs to the perturbations using voluntary feed intake as response criterion. The response of a pig to a perturbation is characterized by four parameters. The start and end times of the perturbation are ‘imposed’ by the perturbing factor, while two other parameters describe the resistance and resilience potential of the pig. One of these describes the immediate reduction in daily feed intake at the start of the perturbation (i.e., a ‘resistance’ trait) while another parameter describes the capacity of the pig to adapt to the perturbation through compensatory feed intake to rejoin the target trajectory of feed intake (i.e., a ‘resilience’ trait). The procedure has been employed successfully to identify the target trajectory of feed intake in growing pigs and to quantify the pig’s response to a perturbation
Production de biomasse et immobilisation de carbone et d’azote sur des sols marginaux : cas de taillis à très courte rotation conduits sans fertilisation
No full textDescription du sujet. Cet article présente les productions de biomasses aériennes et souterraines de jeunes taillis à très courte rotation, non fertilisés, plantés sur des sols marginaux.
Objectifs. Deux sols contrastés ont permis de suivre la croissance de saule, peuplier et robinier pour estimer leur production de biomasse exportable, l’immobilisation de carbone et d’azote dans les racines, et quantifier les restitutions au sol par la sénescence foliaire. Une comparaison de deux densités de robinier (2 500 vs 5 000 pieds·ha-1) est également réalisée.
Méthode. Les dispositifs sont instrumentés afin de quantifier le carbone (C) et l’azote (N) impliqués dans i) la sénescence foliaire retournant au sol, ii) les exportations et immobilisations de deux récoltes.
Résultats. Le C total immobilisé en seconde récolte varie de 7,8 à 16,1 t·ha-1 et l’azote de 125 à 393 kg·ha-1. La sénescence foliaire restitue au sol 15 à 22 % du C total fixé, tandis que 17 à 31 % est immobilisé dans les racines. L’azote restitué au sol par la sénescence a varié de 48 à 79 kg·ha-1, soit respectivement 38 à 20 % du total, et celui retrouvé dans les racines a varié de 22 à 48 % du total. Nous n’avons pas constaté d’effet de la densité de plantation sur les différents compartiments des robiniers.
Conclusions. Saule et robinier ont su mieux s’adapter que le peuplier aux conditions difficiles rencontrées. La fixation d’azote symbiotique du robinier pourrait être mieux exploitée pour accroitre la production de biomasse d’autres espèces, en cultures mixtes par exemple.Description of the subject. This article presents the aboveground and belowground biomass balances of young non-fertilized short-rotation coppices, planted on marginal soils.
Objectives. On two contrasting soils, the growth of willow, poplar and black locust was monitored firstly, to estimate their harvested biomass production, and the immobilization of root-derived carbon and nitrogen, and secondly, to quantify the restitutions occurring at the soil surface through leaf senescence. A comparison of two densities of black locust (2,500 vs 5,000 feet·ha-1) was carried out.
Method. The devices used were instrumented to quantify the levels of carbon (C) and nitrogen (N) involved in: i) leaf senescence returning to the soil, ii) exports by the two harvests.
Results. The total C immobilized in the second harvest oscillated from 7.8 to 16.1 t·ha-1, and the total N from 125 to 393 kg·ha-1. Leaf senescence corresponded to 15 to 22% of the total C on the soil surface, while 17 to 31% was immobilized in the roots. The N released into the soil by senescence varied from 48 to 79 kg·ha-1, i.e. 38 to 20% of the total respectively, and ranged and the one in the roots ranged from 22% to 48% of the total. We did not find an effect of planting density on different compartments of black locust.
Conclusions. Willow and black locust have adapted better to the difficult conditions encountered than poplar. The symbiotic nitrogen fixation of black locust should be better exploited to increase the biomass production of other species, in mixed crops for example
Late weaning is associated with increased microbial diversity and Faecalibacterium prausnitzii abundance in the fecal microbiota of piglets
No full textBackground: 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
Sinorhizobium meliloti succinylated high-molecular-weight succinoglycan and the Medicago truncatula LysM receptor-like kinase MtLYK10 participate independently in symbiotic infection
No full textThe formation of nitrogen-fixing nodules on legume hosts is a finely tuned process involving many components of both symbiotic partners. Production of the exopolysaccharide succinoglycan by the nitrogen-fixing bacterium Sinorhizobium meliloti 1021 is needed for an effective symbiosis with Medicago spp., and the succinyl modification to this polysaccharide is critical. However, it is not known when succinoglycan intervenes in the symbiotic process, and it is not known whether the plant lysin-motif receptor-like kinase MtLYK10 intervenes in recognition of succinoglycan, as might be inferred from work on the Lotus japonicus MtLYK10 ortholog, LjEPR3. We studied the symbiotic infection phenotypes of S. meliloti mutants deficient in succinoglycan production or producing modified succinoglycan, in wild-type Medicago truncatula plants and in Mtlyk10 mutant plants. On wild-type plants, S. meliloti strains producing no succinoglycan or only unsuccinylated succinoglycan still induced nodule primordia and epidermal infections, but further progression of the symbiotic process was blocked. These S. meliloti mutants induced a more severe infection phenotype on Mtlyk10 mutant plants. Nodulation by succinoglycan-defective strains was achieved by in trans rescue with a Nod factor-deficient S. meliloti mutant. While the Nod factor-deficient strain was always more abundant inside nodules, the succinoglycan-deficient strain was more efficient than the strain producing only unsuccinylated succinoglycan. Together, these data show that succinylated succinoglycan is essential for infection thread formation in M. truncatula, and that MtLYK10 plays an important, but different role in this symbiotic process. These data also suggest that succinoglycan is more important than Nod factors for bacterial survival inside nodules
