eKhSACIR інституційному репозитарії Харківської державної академії культури
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A first demonstration of realized selection response for fillet yield in fish, in rainbow trout oncorhynchus mykiss
No full textun poster présent
Microbial community assemblies and interspecific interactions in wheat sourdough
No full textMicrobial community assemblies are largely studied in complex environments such as ocean, gut or soil communities. Although our knowledge of microbial communities’ diversity has been largely enhanced by the use of –omics technics in the last decade, observations as well as experimental and theoretical works are needed to decipher the ecological processes governing their patterns of biodiversity and how the species forming these communities interact together. Here, we address these questions in the case of wheat sourdough microbial communities. Sourdough communities are always composed of an assemblage of lactic acid bacteria and yeasts but species composition vary between sourdoughs. As these communities are relatively simple in terms of species richness, they can represent a good opportunity to study the role of abiotic conditions and biotic interactions on community assemblies. It has been hypothesized that yeasts and LAB interact together mainly in a non-competitive way through mutualistic supply of important metabolites, such as glucose release by LAB, or vitamins release by yeasts to the benefits of each other. However interspecific interactions in sourdough have not been extensively studied. We used two kind of approaches to investigate these interactions: i) an analysis of the network of sourdough yeast and LAB species documented in the literature to determine whether some species tend to co-occur more (or less) often than expected in the absence of interactions, ii) mono and co-culture of yeast and LAB strains sampled in natural sourdough to characterize yeast-LAB interactions. We have shown that LAB presence tends to decrease yeast density whereas yeast presence tends to decrease LAB density although results are contrasted depending on species and strains. Further work is needed to unravel the mechanisms shaping these interactions
Effects of dietary arginine supplementation to primiparous mares in the last third of gestation on foal birthweight and placental function
No full textNational audienc
Questioning the sustainability of quantitative physiological resistance : epidemiological and evolutionary responses of foliar fungal pathogens to changes in wheat plant traits
No full textInternational audienceCrop pathogens are known to rapidly adapt to agricultural practices. Although cultivar resistance breakdown and resistance to pesticides have been broadly studied, little is known about the adaptation of crop pathogens to more quantitative traits such as quantitative resistance. Quantitative resistance could be more sustainable than gene for gene resistance because it exerts a lower selective pressure on pathogens and relies on a variety of plant traits (and probably genes) rather than on a single one. Using a modelling approach, in this study we address the epidemiological and evolutionary responses of the pathogen to changes in several plant traits that impact epidemic development. With the model, we study life history evolution of biotrophic fungal pathogens of wheat. We focus on a single pathogen life history trait, the latent period, which directly determines the amount of resource allocated to growth and reproduction alongside the speed of canopy colonization. We investigate the evolutionary response of pathogens to changing several plant traits such as leaf metabolite concentration, leaf dimension and leaf lifespan. These plant traits impact epidemic development: disease severity is predicted to increase with metabolite content and leaf lifespan. We compare predictions of latent period evolution based on different “empirical” fitness measures such as annual spore production or within-season exponential growth rate, with predictions based on the more rigorous concept of invasion fitness from adaptive dynamics theory. For each of the studied plant traits, we use pairwise invisibility plots to identify evolutionarily stable strategies of the latent period (ESS). The ESS latent period responds differently to the different plant traits: it is longer on plants with long-lasting leaves and shorter on plants with bigger leaves leading to denser canopies. Our results further reveal that early canopy colonization during crop development might be a critical factor determining the issue of between-strain competition and shaping pathogen adaptation in the context of plant quantitative resistance. Finally, we argue that landscape-level heterogeneity may induce maladaptation of the pathogen that may be useful in stalling the evolutionary breakdown of quantitative resistanc
Estimating the part of residual energy intake associated with real differences in feed efficiency and not with errors in dairy cows
No full textTake home message When accurate high throughput monitoring and a steady environment are used, the variability of residual feed intake is only 8% of the variability of energy intake in Holstein cows over a full lactation. Even in these experimental conditions, only 59% out of these 8% are really associated with feed efficiency differences and not with errors. Introduction Reducing the use of resources to maintain production and decrease dairy cow impact on the environment is a major challenge to tackle and is known as improving feed efficiency. Feed efficiency is often estimated with the residual intake defined as the difference between the actual feed intake and the feed intake predicted from the energy consumed or produced by the major biological functions (lactation, body reserves gain and loss and maintenance) (Berry and Crowley, 2013). As residuals of a statistical model, residual intake does not only include feed efficiency differences, but also the accumulated errors of model fitting and errors of measurement. Aggrey and Rekaya (2013) in broilers and Savietto et al., (2014) in beef cattle used a mixed model with random animal effect to isolate the REI only associated with animal feed efficiency differences and not with errors. The objective of the present study was to estimate the part of residual intake variability in dairy cows really associated with feed efficiency differences and less with errors, thanks to a mixed model with random animal effect (Fischer et al., 2017). Material & methods Holstein cows were housed in a free-stall barn and fed with a single TMR based on corn silage and concentrates during the whole lactation. One hundred and nineteen cows were monitored throughout the first 238 days in milk for daily individual feed intake as the difference between offered dry matter and next morning refusals dry matter. All cows were also monitored for morning body weight after milking, daily milk yield, twice a week daily milk protein, fat and lactose, and monthly body condition score with a 0.25 increment scale going from 0 for an emaciated cow to 5 for a fat cow. Feed efficiency was estimated as the residual energy intake (REI): the residual of the linear regression of average net energy intake on average net energy in milk, average metabolic body weight and body condition score gain and loss, both multiplied by average body weight. To estimate the REI associated with feed efficiency and not with errors, the variables used to estimate REI - milk yield and composition, body condition score change, feed intake and body weight - were averaged per 2 week period to create repeated measures per cow during the 238 monitored days. A mixed model was then fitted with random cow-specific slopes for the variables and a random cow-specific intercept. The difference between the energy intake predicted with the cow-specific regression slopes and intercept and the energy intake predicted with the population average slopes and intercept was interpreted as animal variability in feed efficiency and not the error. Results & discussion The variability of REI represented 8% of the variability of the actual net energy intake among the 119 Holstein cows over near the whole lactation. Of this 8% of REI variability, the cow-specific part isolated with the mixed model was only 59%. By definition, this 59% of REI variability is repeatable throughout time and associated with cows, and thus could be considered as feed efficiency differences. However, certain types of errors can be repeatable throughout time and associated with cows, such as sorting feed. The remaining 41% is by definition not repeatably specific to cows throughout time and therefore most probably associated with model fitting errors or measurement errors. However, when temporary events such as clinical mastitis, only affect intake or only affect a biological function, then it is cow-specific, but is not repeatable throughout time and will be included in the error of the mixed model and thus not considered as feed efficiency. Conclusion When using high throughput monitoring of individual feed intake and of the major energy consuming functions in dairy cows fed with a single high energy diet during the whole lactation, residual energy intake differences among Holstein cows are only 8% of the total variability of feed intake. Thanks to a mixed model with cow-specific regression slopes and intercept, we were able to identify that of this 8%, only 59% may be associated with feed efficiency differences and not with model fitting errors or measurement errors
Genomic evaluation on the French scale of Holstein bulls from a large Indian NGO
No full textInternational audienc
Feedback loops between traits under selection and the environment in batch experimental evolution: a mathematical analysis
No full textFeedback loops between traits under selection and the environment in batch experimental evolution: a mathematical analysis. Second Joint Congress on Evolutionary Biology (EVOLUTION 2018
Selection of cell lines for the functional validation of 3D genomic interactions by genome editing
No full textInternational audienceNumerous studies have pointed out the major role of 3D nuclear architecture in the regulation of gene expression. Individual chromosomes occupy discrete territories in the nucleus but chromosomal regions often loop out and neighboring chromosomes can intermingle resulting in potential functional contacts between genomic regions from the same or different chromosomes.These cis- and trans-interactions could contribute to gene expression regulation by facilitating the consolidation of co-regulated genes in specific transcription factories. Thus, their dynamic recruitment could result in activation or abatement of gene transcription. In this context, we investigated by means of DNA fluorescence in situ hybridization (FISH) the 3D genome organization in porcine fetal muscle cells particularly long-range chromatin interactions implicating the imprinted loci IGF2 (SSC2) and other loci located on different chromosomes (Lahbib-Mansais et al. 2017). We showed that IGF2 alleles associate with the reciprocally imprinted DLK1/MEG3 region (SSC7). We furthermore demonstrated that these trans-interactions preferentially occurred between the expressed alleles. To prove their suggested functional character, we tested cell lines in which we plan to delete the genomic region containing IGF2 to determine if this deletion compromises the occurrence of the interactions. The first step has consisted in analyzing different types of porcine cell lines (4 somatic cell hybrid clones, an iPS cell line, a primary muscle and a permanent cell lines) to determine if they could be a good cell model for this purpose. Both 2D and 3D FISH experiments were performed to verify the presence in these cell lines of: i) the target chromosomes/genes, ii) the genomic interactions between IGF2-DLK1 and IGF2-MEG3. The expression of all target genes was also analyzed.We were able to select one cell line for which we plan to delete IGF2 by CRISPR-Cas9 to determine if this implies the modification of the interactions
Meta-analysis of relationships between mastication time, particles retention time and dry matter intake in cattle
No full textSession 6: Feed conversion efficiency towards productivity and reduction of excretaNational audienc
