Portail Hal-l'Institut Agro Rennes-Angers
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Characterization of peptides released from gluten-free climate-smart cowpea-based pasta during gastric and intestinal in vitro digestion
No full textInternational audienceFour nutritionally optimized cowpea-based pasta incorporating or not teff and/or amaranth leaves underwent in vitro static gastro-intestinal digestion using the Infogest model. The aim of this study was to characterize the peptides released at the end of the gastric and intestinal phase of cowpea-based pasta compared to wheat-based pasta controls with an increasing fiber content, using SDS-PAGE and mass spectrometry. At end of intestinal phase, the four cowpea-based pasta presented slightly lower peptides number of similar size compared to wheat-based pasta, which could indicate a lower proteolysis. Additionally, no significant difference in origin of peptide profile was observed with teff or amaranth leaf additions within cowpea-based pasta, nor with the increase of fiber within wheat-based pasta. Peptide released from cowpea-based pasta mainly comes from cowpea proteins, and especially globulins “RmlC-jelly roll fold” and “11S-seed storage protein”. Vigilance is required for these globulin which have putative allergenic epitopes on their sequences
Body weight variation is a good proxy of abdominal fat weight in laying hens at 90 weeks of age
No full textInternational audienceBody reserve levels are known to influence production performance and longevity in livestock species, and their management is therefore of interest for breeding programs. In laying hens, we have recently demonstrated that abdominal fat weight (AFW) at the end of the production cycle is genetically correlated with key economic traits, being positively correlated with laying rate and negatively correlated with egg weight at 90 weeks of age. While AFW is not a primary selection objective, controlling it can contribute to improving both metabolic efficiency and reproductive performance. Direct measurement of AFW, however, requires slaughter and dissection, preventing its use as a routine selection criterion. As an alternative, we evaluated in this study the potential of using body weight difference between two adult ages (DBW) as a non-invasive proxy for AFW in late-stage laying hens. In aging hens, body weight variation is expected to largely reflect changes in body reserves.Genetic parameters were estimated for AFW (measured at 90 weeks in 1,114 hens) and for DBW between 30 and 70 weeks (DBW70) or between 30 and 90 weeks (DBW90), traits available for much larger datasets (9,656 and 1,657 hens, respectively) due to their non-invasive nature. Very high genetic correlations were observed between AFW with DBW70 (0.75) and DBW90 (0.78), supporting the hypothesis that around three quarters of the genetic variance in AFW is captured by DBW. It can be noted that the correlation between back fat thickness (BFT) and DBW were lower, 0.45 and 0.46, respectively, suggesting that these two body reserve traits are distinct traits, despite the relatively high overall genetic correlation of 0.67 observed between them. This observation is consistent with a previous study (Bédère et al 2025). To go further in the genetic characterization of these traits, genome-wide association studies (GWAS) were conducted for DBW70, and DBW90 and compared with those obtained previously for AFW (3 QTLs on chromosomes 2, 8 and 28) using hens with available genotypes for a 60k SNP Array imputed on a 600k SNP array. We identified 3 QTLs for DBW70 and 2 for DBW90 and no QTLs were shared between the DBW traits and AFW.Overall, this study demonstrates that DBW traits are reliable and heritable non-invasive proxies for AFW in laying hens at 90 weeks. The strong genetic correlation between these traits, particularly with DBW70 as an earlier measurement, opens opportunities for indirect selection to control abdominal fat deposition at later production stages. The absence of common QTLs between AFW and DBW traits, suggests that major-effect genomic regions may differ between traits and their strong genetic correlation are largely polygenic in nature, driven most probably, by many small-effect causal variants that remain undetectable by GWAS at current sample sizes.These results provide practical insights for breeding programs aiming to optimize body reserve management and sustain production performance in extended laying cycles.This project is funded by the European program GEroNIMO N°101000236 and ANR ‘EFFICACE’ program
Lipid traits related to body reserves and egg yolks of laying hens at 90 weeks of age: QTL detection and genetic correlations with production traits
No full textInternational audienceExtending the productive lifespan of laying hens beyond the conventional 70 weeks offers a promising strategy to improve the sustainability and economic efficiency of egg production, while addressing ethical and environmental concerns. However, maintaining high production performance in aging hens requires understanding the genetic basis of lipid metabolism at advanced ages. Lipid metabolism is central to reproductive function in poultry, not only because yolk formation demands substantial lipid investment, but also because lipids provide precursors for steroid hormones and signaling molecules that regulate ovulation and egg production. However, abdominal fat weight (AFW), and yolk percentage (YP), despite being key indicators of lipid dynamics, remain poorly characterized from a genetic perspective at advanced production stages. In this study, genomic architecture of lipid-related traits (AFW, YP) and their genetic parameters with production traits (egg weight, EW; laying rate, LR) were investigated in hens at 90 weeks of age. Liver weight (LW) was included as this organ is the main site of lipid synthesis. These analyses were performed by using an experimental population of up to 7,000 Rhode Island Red hens genotyped with 60k SNP arrays imputed on 600k. Genome-wide association studies (GWAS) were followed by linkage disequilibrium (LD)-based QTL refinement. Considering the hypothesis of causal genetic variants affecting hepatic gene expression, GWAS results were integrated with liver expression quantitative trait loci (eQTL) detected at the same age, enabling the identification of candidate genes whose expression may mediate genetic effects on phenotypes.Heritability estimates for AFW and YP were high (0.48 and 0.51) and comparable to values reported in broilers and layers. Positive genetic correlations of AFW and YP with LR (0.24 and 0.27) suggest that moderate lipid reserves might sustain laying performance at advanced ages, contrasting with negative correlations in younger hens. Conversely, negative correlations of AFW and YP with EW ( 0.16 to 0.54), point to a trade-off between lipid allocation to yolk and abdominal fat reserve and overall egg mass. LW was strongly correlated to YP (0.53) likely reflecting the high contribution of liver-derived lipids to yolk formation, whereas correlations with AFW and LR are only moderate (0.19 and 0.27).GWAS identified several QTLs associated with lipid-related traits. A new locus on chromosome 8 was detected for both AFW and YP, although LD analysis suggested distinct underlying causal variants. Known QTLs for abdominal fat percentage were confirmed on chromosomes 2 and 28. LD-based refinement reduced QTL intervals, improving candidate gene prioritization. For AFW QTL integration with liver eQTLs highlighted several promising regulatory candidate genes, including CYB5A and GDF15 at the chromosome 2 and 28 and for YP the gene OSBPL9 on chromosome 8.These results demonstrate that substantial genetic variability for lipid-related traits persists at advanced ages and are correlated with key production traits. New candidate genes were identified through LD based QTL refinement and hepatic eQTL integration. These findings provide a genomic basis for breeding strategies aimed at improving metabolic efficiency in laying hens during extended production cycles.This project is funded by the European program GEroNIMO N°101000236 and ANR ‘EFFICACE’ program
Branching Varies with Light Limitation Scenarios in relation with Changes in Carbon Source-Sink Dynamics
No full textInternational audienceAbstract Bud outgrowth is a major component of plant architectural plasticity and is influenced by light conditions. While the inhibitory effect of low light intensity on branching is well documented, the underlying regulators remain debated and, especially, the role of sugar availability has never been thoroughly evaluated. Here, we combined experiments with a computational approach quantifying carbon source-sink balance in single-axis rose plants to investigate how continuous and transient light limitation regulate bud outgrowth. Continuous low light reduced photosynthesis, leading to decreased sugar availability and inhibited bud outgrowth. In contrast, a transient period of low light followed by high light unexpectedly stimulated bud outgrowth, shortened the delay between outgrowth of successive buds, and produced an over-branched phenotype. This response resulted from a non-reversible reduction in the growth of apical organs appearing under low light, which lowered carbon demand and caused sugar over-accumulation after the return to high light. Manipulating carbon supply and demand through leaf masking, photosynthetic inhibition, and targeted sucrose feeding causally confirmed the central role of sugar availability in these contrasting responses. Beyond these findings, key requirements for models simulating branching plasticity were identified and this work provides a basis for predicting branching responses under fluctuating and complex light environments. Highlight Bud outgrowth, a key component of plant plasticity, is regulated by light intensity through sugar availability. Continuous and transient low light have opposite effects by limiting sugar production and use, respectively
Decoding the sugar–strigolactone crosstalk: new frontier in plant growth and stress resilience
No full textInternational audienceAbstract Plants continuously integrate metabolic and hormonal signals to coordinate growth, development, and responses to environmental stimuli. Among these signals, sugars and strigolactones (SLs) have emerged as central regulators. Beyond serving as metabolic fuels, sugars act as signaling molecules that govern key developmental transitions and stress responses. SLs, a relatively recent addition to the phytohormone family, play pivotal roles in shaping plant architecture, modulating resource allocation, and facilitating environmental adaptation. While the individual signaling functions of sugars and SLs are well documented, their crosstalk remains an emerging and largely underexplored area of plant biology. This review synthesizes current knowledge on both the independent and interactive roles of sugar and SL signaling across critical developmental processes, including seed germination, hypocotyl elongation, root and shoot architecture, flowering, senescence, and plant responses to abiotic and biotic stress. By analyzing antagonistic and synergistic interactions, we point out several potential integrative hubs where metabolic and hormonal signals converge to fine-tune the final decision. Notably, the nodal roles of BRC1/TB1 (BRANCHED1/TEOSINTE BRANCHED1), FT (FLOWERING LOCUS T), in mediating sugar–SL crosstalk in shoot branching, flowering, respectively, are highlighted. We also explore how sugar-SL interplay influences seed germination and plant adaptation to environmental stresses through shared regulators such as TOR (Target of Rapamycin) kinase, SnRK1 (Sucrose non-fermenting-1 Related Kinase 1), and SMXLs (Suppressor of MAX2-Like proteins). Understanding these interactions not only deepens our knowledge of fundamental plant biology but also offers new insights for improving the performance and resilience of crop and horticultural species
Coupled bulk and surface mechanisms lead to whey protein deposits under shear
No full textInternational audienceUnderstanding the mechanisms behind fouling deposit formation remains an unsolved challenge for the dairy industry. While the effect of temperature is well-established, few studies have explored the impact of shear rate, a key parameter in dairy processing. Therefore, this study investigates the growth of surficial deposits and bulk aggregates originating from whey protein solutions under shear. Whey protein solutions with different concentrations (5-12 wt%) were sheared at fixed rates (0-175 s -1 ), using a cone-and-plate rheometer, at 65 • C to minimize thermal denaturation.Results show that the area covered by the deposits increases by up to fivefold under shear, particularly in concentrated conditions, compared with that observed at rest. This is accompanied by the complexification of deposit morphology, from sparse globular clusters to branches structures interconnecting into gels at 12 wt%. In contrast, solution dynamics are mostly affected by protein concentration rather than shear, resulting in the formation of submicronic aggregates. Two interpretive hypotheses are discussed: i) heat favors whey protein denaturation and the formation of aggregates increasingly colliding with the surface under shear and ii) active surface deposits, formed by these collisions, interconnect with flowing aggregates, particularly at high protein concentrations. The examination of surface and bulk dynamics presented in this study provides deeper insights into fouling mechanisms. They offer potential applications in other areas where protein denaturation/aggregation plays a crucial role.</p
Combining LD-Guided QTL Refinement, GEGA Annotation, and Tissue-Specific eQTL for Candidate Gene Prioritization
No full textInternational audienceQuantitative trait loci (QTL) mapping is a powerful approach to dissect the genetic architecture of complex traits. However, the broad size of QTL intervals often hampers the identification of causal genes, limiting both functional interpretation and genomic selection. To overcome this limitation, we developed a workflow that refines QTL intervals using linkage disequilibrium (LD) between each SNP and its leader SNP. Once refined, the gene content of each region can be rapidly explored using the GEGA website (https://gega.sigenae.org/), which provides gene listing, functional annotations, and expression profiles across 47 tissues. Both protein-coding and long non-coding genes are included. This framework was applied to several traits of interest in hens to reduce QTL size and prioritize biologically relevant candidate genes.QTLs were obtained with GCTA and initially defined as ±500kb around the leader SNP. LD between each SNP and its leader SNP was computed chromosome by chromosome with PLINKv1.9, retaining SNPs with LD≥0.5. Refined boundaries were set by the most distal upstream and downstream SNPs still above this threshold. This LD-guided procedure greatly reduced QTL size. For example, the chromosome 12 QTL for Haugh unit (HU) shrank by 92% (from 1Mb to 76kb), reducing gene count from 143 to 9. The chromosome 18 QTL for egg weight (EW) decreased by 90% (from 1Mb to 102kb), reducing genes from 107 to 14.Following refinement, functional characterization was performed using GEGA. In the HU QTL, six protein-coding genes were identified, mostly ubiquitously expressed, with one gene showing specificity in the oviduct and blood, tissues relevant for albumen quality. Keyword searches related to viscosity, egg proteins or glycosylation did not retrieve genes in this interval. In the EW QTL, several genes showed tissue-specific expression in the oviduct or neuroendocrine axis (pituitary, hypothalamus). A keyword search related to hormonal regulation highlighted GALR2, consistent with its role in follicular growth and its expression in the gizzard and oviduct.Beyond this workflow, additional insights can be gained when transcriptomic data are available for tissues biologically linked to the phenotype. This is the case for traits related to lipid metabolism, for which the liver is the central organ. In the context of abdominal fat weight (AFW), we analysed a QTL located on chromosome 28 using hepatic RNA-seq data from 459 hens. After refining the QTL using LD, gene expression levels were used to detect local and distant-eQTL, and colocalization between QTL and eQTL signals was assessed. This strategy identified a lipid gene CRTC1 and its long-non-coding RNA as candidate genes, whose local-eQTLs showed LD profiles highly consistent with the AFW QTL LD pattern makes it biologically coherent with the phenotype. This example demonstrates how integrating tissue-specific eQTL enables prioritization of causal genes based on regulatory mechanisms.Overall, combining LD-guided QTL refinement, GEGA-based annotation, and tissue-specific eQTL colocalization provides an efficient strategy to narrow genomic intervals, identify functional candidates, and pinpoint regulatory variants underlying key production traits in poultry, enhancing interpretability and accelerating causal gene discovery.This project is funded by European GEroNIMO N°101000236 and ANR ‘EFFICACE’ projects
Dry-Heating-Induced Microparticles of β-Lactoglobulin: Understanding the Respective Role of Alkaline pH and Lactose
No full textInternational audienceWhen whey proteins are stored in solution at 4 °C and pH 9.5 in the presence of lactose and then dried, dry-heating (DH) of the powder at 100 °C leads to the formation of protein–protein cross-link within the powder particles. Suspensions of the dry-heated powder consist of microparticles with sizes similar to those of the original powder grains, which entrap large amounts of water for functional purposes. In this work, the denaturation and aggregation of pure β-lactoglobulin (β-Lg) and the yield of its conversion into microparticles were characterized at different stages of the process under different conditions (pH, presence of lactose, sucrose, and ammonium chloride) to gain insight into the mechanism of microparticle formation. Qualitatively, only limited changes in the secondary structure of β-Lg were shown during storage of β-Lg solution at pH 6.5 and 9.5. However, increased denaturation and aggregation with prolonged storage at pH 9.5 promoted microparticle formation. β-Lg aggregates formed during storage at pH 9.5 were precursors for their DH-induced cross-linking into microparticles in the presence of Maillard reaction products
