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Le chant est une pratique vocale mettant en jeu de multiples dimensions du corps humain, ce dernier se modulant véritablement à l’effort phonatoire instigué par le sujet chantant. Le changement de mécanisme laryngé en est le parfait témoignage, nécessitant une grande adaptation des cordes vocales. Bien que cet instant, parfois redouté par les chanteurs, soit encore discuté dans son déroulé exact, nous lui connaissons des modifications anatomiques indéniables. Cependant, les effets physiologiques que cet événement peut avoir sur le métabolisme et le corps humain sont, jusqu’alors, inconnus.Effectivement, si les répercussions physiologiques que la pratique du chant a sur notre biologie interne ont déjà été étudiées, l’instant précis du changement de mécanisme laryngé, lui, n’a pas fait l’objet de recherches spécifiques.L’idée d’une étude analysant le potentiel stress physiologique généré par un changement de mécanisme laryngé, entre M1 et M2, en voix chantée a alors émergé. Cette étude exploratoire a pour but de répondre à cette absence dans la littérature scientifique, en se basant sur un protocole expérimental faisant intervenir des sujets chanteurs et non-chanteurs, hommes comme femmes.Nous avons enregistré des sirènes vocales sur différentes hauteurs afin de générer un changement de mécanisme laryngé et nous avons également mesuré un ensemble de paramètres physiologiques parallèlement à ces vocalisations. Nous avons ensuite procédé à une analyse physiologique, ainsi qu’à des analyses perceptives. Notre étude a mis en avant des résultats intéressants concernant les analyses perceptives de ces instants de changement de mécanisme, à nuancer cependant en raison de la partie physiologique qui n’a malheureusement pas abouti, faute à un protocole expérimental certainement peu sensible.Néanmoins, cette étude permet d'ouvrir la voie à d’autres recherches physiologiques donnant peut-être, à terme, de nouvelles dimensions du soin orthophonique dans l’accompagnement vocal.

International audience; Climate change is rapidly modifying marine fish assemblages in the Arctic. As fish eggs and larvae have a narrower thermal tolerance than nonreproductive adults, their response to increasing temperatures is likely one of the main drivers of these changes. In this study, we described ichthyoplankton assemblages in West Greenland between 62 and 73 °N, during summers 2017–2019, and investigated the relationship between sea surface temperature in the spring and summer and the survival of Arctic cod (Boreogadus saida (Lepechin, 1774)) early life stages over the hatching season. Warm years were associated with partial recruitment failures resulting from thermal stress to the eggs and larvae hatched late in the season. Using past environmental conditions, we forecasted an imminent decline in Arctic cod recruitment in the regions of Uummannaq and Disko Bay. Observations from fjords suggested that glacial meltwater could create a subsurface thermal refuge allowing Arctic cod larvae to survive despite very high summer sea surface temperature (ca. 10 °C). As the Greenland ice sheet is melting at an unprecedented speed, the mechanism underlying the “glacial meltwater summer refuge hypothesis” could curb some of the negative effects of ocean warming on the survival of young Arctic cod in West Greenland and other Arctic fjord systems.

The invasive mosquito Aedes japonicus japonicus (Theobald, 1901) settled in 2013 in the Alsace region, in the northeast of France. In this temperate area, some mosquito species use diapause to survive cold winter temperatures and thereby foster settlement and dispersal. This study reports diapause and its seasonality in a field population of Ae. japonicus in the northeast of France. For two years, eggs were collected from May to the beginning of November. They were most abundant in summer and became sparse in late October. Diapause eggs were determined by the presence of a fully developed embryo in unhatched eggs after repeated immersions. Our study showed effective diapause of Ae. japonicus in this part of France. At the start of the egg-laying period (week 20), we found up to 10% of eggs under diapause, and this rate reached 100% in October. The 50% cut-off of diapause incidence was determined by the end of summer, leading to an average calculated maternal critical photoperiod of 13 h 23 min. Interestingly, diapause was shown to occur in part of the eggs even at the earliest period of the two seasons, i.e. in May of each year. Even though we observed that the size of eggs was positively correlated with diapause incidence, morphology cannot be used as the unique predictive indicator of diapause status due to overlapping measurements between diapausing and non-diapausing eggs. This study provides new knowledge on diapause characterisation and invasive traits of Ae. japonicus.Caractérisation de la diapause et saisonnalité d’Aedes japonicus japonicus (Diptera, Culicidae) dans le nord-est de la France.Aedes japonicus japonicus (Theobald, 1901), un moustique invasif, s’est installé en 2013, en Alsace, dans le nord-est de la France. Dans une telle région tempérée, certaines espèces de moustiques ont recours à la diapause pour survivre aux températures froides de l’hiver, ce qui favorise donc l’établissement et la dispersion de ces espèces. Cette étude montre le phénomène de diapause et la saisonnalité d’une population sauvage d’Ae. japonicus dans le nord-est de la France. Pendant deux ans, les œufs ont été collectés de mai à début novembre. Ils étaient plus abondants durant l’été et plus rarement présents en octobre. Les œufs diapausants ont été déterminés par la présence d’un embryon entièrement développé dans les oeufs non éclos après des immersions répétées. Notre étude a mis en évidence une diapause effective d’Ae. japonicus dans le nord-est de la France. Au début de la période de ponte (semaine 20), jusqu’à 10 % des œufs a été trouvé à l’état de diapause et ce taux atteint 100 % en octobre. Un taux de 50 % de diapause a été atteint à la fin de l’été, amenant à une photopériode critique maternelle calculée de 13 heures 23 minutes en moyenne. De façon intéressante, il a été montré que la diapause se produisait chez une partie des œufs, et ce même dès le début des deux saisons, en mai de chaque année. Bien que nous ayons observé que les mesures des œufs étaient positivement corrélées avec le taux de diapause, la morphologie des œufs seule ne peut pas être utilisée comme unique indicateur de prédiction du statut de diapause, à cause d’un chevauchement des mesures entre les œufs diapausants et non diapausants. Cette étude offre de nouvelles connaissances sur les caractéristiques de la diapause et sur les traits d’invasion d’Ae. japonicus.

International audience; The eggs of Echinococcus multilocularis, the infectious stage, are spread into the environment through wild and domestic carnivore faeces. The spatial location of the faeces containing infective E. multilocularis eggs is a key parameter for studying areas of exposure and understanding the transmission processes to the intermediate hosts and humans. Echinococcus multilocularis faecal prevalence is often assessed by detecting E. multilocularis DNA, not necessarily eggs. This work aimed to determine the percentage of faeces containing E. multilocularis eggs in a rural town and its surroundings and whether this level of precision is relevant in assessing exposure to E. multilocularis. For this purpose, we developed a combined molecular and microscopic approach to investigate the E. multilocularis exposure of potential hosts in the environment from field-collected carnivore faeces. Carnivore defecation patterns were then spatialized to study the spatial distribution of E. multilocularis. Faeces were screened for E. multilocularis DNA using a specific real-time quantitative PCR (qPCR). Echinococcus multilocularis eggs were morphologically identified from E. multilocularis-specific qPCR-positive faeces after sucrose flotation and individually confirmed through specific PCR and sequencing. The spatial distribution of E. multilocularis was studied using Kulldorff statistics. Echinococcus multilocularis eggs were identified mostly in fox faeces positive for E. multilocularis DNA by qPCR (n = 27/70) and only from 1 of 15 copro-samples from dogs and 1 of 5 from cats. The faecal prevalence of E. multilocularis DNA and eggs was overdispersed, with the same geographical patterns. These data suggest that E. multilocularis DNA and/or egg detection in carnivore faeces, mainly that of foxes, is appropriate in ecological studies of E. multilocularis transmission.

Concomitantly with the development of the embryo and extra-embryonic structures, initial chicken egg defenses are progressively altered, which suggests that alternative mechanisms appear to protect the embryo until hatching. To better understand the role of extra-embryonic fluids in the chicken egg defense during incubation, we analyzed the biochemical composition and antibacterial properties of the chicken amniotic and allantoic fluids. As for humans, the chicken amniotic fluid protects the embryo against mechanical shocks and microbial infections. Moreover, at the 12th day of incubation, the transfer of antibacterial molecules from the egg white increases the antibacterial potential of the chicken amniotic fluid, thus protecting the embryo until hatching, and probably after, all along its digestive tract, after oral absorption of the amniotic fluid. Some of these antibacterial proteins are specific to oviparous species and/or birds, which highlights the processes of evolution and adaptation of birds to their terrestrial environment. On the other hand, the antibacterial potential of the allantoic fluid still needs to be explored, but our study demonstrated the presence of active proteases, which could contribute to the digestion and recycling of embryonic metabolic wastes.; Avec le développement concomitant de l’embryon et des structures extra-embryonnaires, les défenses initiales de l’oeuf de poule s’altèrent, ce qui suggère la mise en place de systèmes relais pour protéger l’embryon jusqu’à son éclosion. Pour comprendre le rôle des fluides extra-embryonnaires dans cette fonction, nous avons analysé la composition et les propriétés biochimiques et antibactériennes des fluides amniotique et allantoïque de l’oeuf. Comme chez l’humain, le fluide amniotique chez la poule protège l’embryon contre les agressions physiques et microbiennes. De plus, nous avons démontré que le transfert des molécules antibactériennes du blanc au 12ème jour d’incubation augmente son potentiel antibactérien, assurant ainsi une protection de l’embryon jusqu’à l’éclosion, et probablement après, dans son tractus digestif, après l’ingestion du fluide amniotique. Les spécificités phylogénétiques de certaines des protéines identifiées suggèrent un processus d’adaptation des oiseaux à la flore microbienne terrestre. Pour le fluide allantoïque en revanche, nous n’avons pas pu confirmer son rôle antibactérien, mais nous avons mis en évidence la présence de protéases actives qui pourraient contribuer à la digestion et au recyclage des déchets métaboliques de l’embryon.

International audience; The consumption of private hold poultry foodstuffs, escaping of official maximum residue limit (MRL) controls in the commercial foodstuff, is an important exposure way for the local populations to chlordecone on the French West Indies. Therefore, chlordecone contamination of different tissues in 42 birds from 32 private holders was determined depending on the contamination of the soil of the outside plot but also surveying the rearing practices of these holders of both islands. Chlordecone contents in tissues increased rapidly with this of the topsoil of the site. The most sensitive tissues to chlordecone presence were egg yolk and liver, followed by abdominal fat and finally leg tissue. The rearing practices varied between the surveyed private holders of both islands. Nevertheless, practices for the distribution of feed and water as well as covering of soil were hardly protective, what would increase the exposure risk of these birds to this potentially present soil-bound contaminant. Although depuration of birds seems possible, the ongoing modelization of the necessary time to meet MRL thresholds indicates that such time lapse seems hardly compatible with acceptable delays for private holders. Therefore, very protective rearing practices are the main way to obtain poultry foodstuffs compliant to MRL, what seems possible if the topsoil is contaminated at less than 0.1 mg kg(-1) and perhaps up to 0.5 mg kg(-1) if protective practices vis-a-vis of soil exposure are very strict. Nevertheless, a higher contamination of the topsoil seems not compatible with compliant poultry foodstuffs.

National audience; Cette étude propose de caractériser le non relâchement des plosives finales /p, t, k/ de deux langues d’Asie, tonale (vietnamien) et non tonale (coréen), du point de vue aérodynamique et glottographique. Le comportement glottique (ouverture et fermeture de la glotte, position verticale du larynx) a été examiné en synchronisation avec les valeurs de débits d’air (oral et nasal) pendant les phases de la réalisation consonantique. Les résultats mettent en évidence (1) l’absence de relâchement nasal après l’occlusion de la plosive finale pouvant entraîner une baisse de la pression intraorale, (2) que le larynx s’abaisse systématiquement durant la tenue de la consonne. Cette stratégie de réalisation va dans le sens de notre hypothèse selon laquelle les plosives non relâchées sont produites avec un mécanisme permettant de diminuer la pression intraorale de manière à minimiser le coût articulatoire de la tenue de la closion avec, pour conséquence acoustique, l’absence de burst.

Evaluating the gastrointestinal (GI) fate of proteins is part of the assessment to determine whether proteins are safe to consume. In vitro digestion tests are often used for screening purposes in the evaluation of potential allergenicity. However, the current pepsin resistant test used by the European Food Safety Authority, only corresponds to fasted gastric conditions representative of a late phase adult stomach. In addition, these tests are performed on isolated proteins and the effect of the food matrix and processing are not systematically considered. The aim of this research is to compare three different static in vitro GI scenarios that are physiologically relevant. Namely, an infant, early phase (fed state) adult and late phase (fasted state) adult model. These protocols are applied to well-characterised isolated dairy (β-lactoglobulin and β-casein) and egg (lysozyme and ovalbumin) proteins and the impact of food matrix/processing on their proteolysis is also investigated. A combination of SDS-PAGE, LC-MS/MS and spectrophotometric assay was used for the evaluation of the proteolysis. Results highlight differences across the three GI scenarios whether on isolated proteins or within food matrices. The infant model led to incomplete digestion, leaving intact egg proteins, either isolated or in the food matrix, and intact β-lactoglobulin in the milk. In addition, peptides greater than 9 amino acids were found throughout the intestinal phase for all proteins studied, regardless of the scenario. This reinforces the difficulty of linking protein digestibility to potential allergenicity because many other factors are involved that need further investigation.

Excavation (2008-2014) carried out under the Uffizi Gallery (Florence, Italy) led to the discovery of 75 individuals, mostly buried in multiple graves. Based on Roman minted coins, the graves were preliminarily dated between the second half of the 4th and the beginning of the 5th centuries CE. Taphonomy showed that this was an emergency burial site associated with a catastrophic event, possibly an epidemic of unknown etiology with high mortality rates. In this perspective, paleoparasitological investigations were performed on 18 individuals exhumed from 9 multiple graves to assess the burden of gastrointestinal parasitism. Five out of eighteen individuals (27.7%) tested positive for ascarid-type remains; these are considered as “decorticated” Ascaris eggs, which have lost their outer mammillated coat. Roundworms (genus Ascaris) commonly infest human populations under dire sanitary conditions. Archaeological and historical evidence indicates that Florentia suffered a period of economic crisis between the end of 4th and the beginning of the 5th centuries CE, and that the aqueduct was severely damaged at the beginning of the 4th century CE, possibly during the siege of the Goths (406 CE). It is more than plausible that the epidemic, possibly coupled with the disruption of the aqueduct, deeply affected the living conditions of these individuals. A 27.7% frequency suggests that ascariasis was widespread in this population. This investigation exemplifies how paleoparasitological information can be retrieved from the analysis of sediments sampled in cemeteries, thus allowing a better assessment of the varying frequency of parasitic infections among ancient populations.

Identification and functional characterization of ovarian and maternally-inherited miRNAs in medaka. 7. International Workshop on the Biology of Fish Gametes

International audience; How a nervous system assembles and coordinates a suite of elementary behavioral steps into a complex behavior is not well understood. While often presented as a stereotyped sequence of events, even extensively studied behaviors such as fly courtship are rarely a strict repetition of the same steps in a predetermined sequence in time. We are focusing on oviposition, the act of laying an egg, in flies of the genus Drosophila to describe the elementary behavioral steps or microbehaviors that a single female fly undertakes prior to and during egg laying. We have analyzed the hierarchy and relationships in time of these microbehaviors in three closely related Drosophila species with divergent egg-laying preferences and uncovered cryptic differences in their behavioral patterns. Using high-speed imaging, we quantified in depth the oviposition behavior of single females of Drosophila suzukii, Drosophila biarmipes and Drosophila melanogaster in a novel behavioral assay. By computing transitions between microbehaviors, we identified a common ethogram structure underlying oviposition of all three species. Quantifying parameters such as relative time spent on a microbehavior and its average duration, however, revealed clear differences between species. In addition, we examined the temporal dynamics and probability of transitions to different microbehaviors relative to a central event of oviposition, ovipositor contact. Although the quantitative analysis highlights behavioral variability across flies, it reveals some interesting trends for each species in the mode of substrate sampling, as well as possible evolutionary differences. Larger datasets derived from automated video annotation will overcome this paucity of data in the future, and use the same framework to reappraise these observed differences. Our study reveals a common architecture to the oviposition ethogram of three Drosophila species, indicating its ancestral state. It also indicates that Drosophila suzukii's behavior departs quantitatively and qualitatively from that of the outgroup species, in line with its known divergent ethology. Together, our results illustrate how a global shift in ethology breaks down in the quantitative reorganization of the elementary steps underlying a complex behavior.

Microbial spoilage of liquid egg products and its control by the detection of genetic or chemical markers. journée scientifique "science des aliments et valorisation des bio-produits"

Milk, egg and vegetable combinations for a smart food design to promote environmental sensorial health and safety benefits. STLOpendays

Master

International audience; Stuttering is characterized by respiratory, laryngeal and articulatory peculiarities, especially when the to-be-produced speech is complex. This study examined the glottal behaviour in people who stutter (PWS) during production of simple bilabial (/p/, /b/, /m/) and complex (/pR/, /bR/) onsets. It was hypothesized that the glottal behavior of PWS presented idiosyncrasies, compared to people who do not stutter (PNS) and that these were modulated by the complexity of the onset. Producing semi-spontaneous speech with embedded target words, acoustic and EGG data were collected from 4 PWS and 4 PNS. From the perceptually fluent productions, duration of bilabial occlusion, intensity, open quotient (OQ), difference in intensity, pitch and laryngeal OQ between occlusion-phase and following vowel were measured. No significant differences in glottal behavior were found between PWS and PNS. However, compared to PNS, PWS devoiced voiced consonants significantly more, which motivates a larger-scale investigation with more participants.

Conference: 11th International Symposium on Biometals (Biometals) Location: Ottawa, CANADA Date: 2018; Salmonella enterica serovar Enteritidis (SE) is the most frequently-detected Salmonella in foodborne outbreaks in the European Union. Among such outbreaks, egg and egg products were identifiedas the most common vehicles of infection. Possibly, the major antibacterial property of egg white is ironrestriction, which results from the presence of the ironbinding protein, ovotransferrin. To circumvent ironrestriction, SE synthesise catecholate siderophores (i.e. enterobactin and salmochelin) that can chelateiron from host iron-binding proteins. Here, we highlight the role of lipocalin-like proteins found in eggwhite that could enhance egg-white iron restriction through sequestration of certain siderophores, includingenterobactin. Indeed, it is now apparent that the egg-white lipocalin, Ex-FABP, can inhibit bacterialgrowth via its siderophore-binding capacity in vitro. However, it remains unclear whether Ex-FABP performssuch a function in egg white or during bird infection. Regarding the two other lipocalins of eggwhite (Cal-c and a-1-glycoprotein), there is currently no evidence to indicate that they sequestersiderophores.

International audience; Guinea fowl production is very important for some countries from a socioeconomic and nutritional perspective. Guinea fowl production is low in the Ivory Coast, even if the demand is high. In order to improve understanding of the factors impacting guinea fowl production, a survey was conducted in 2017 in 8 regions (97 farmers) out of a total of 31 regions in Ivory Coast. The aims were 1) to establish a global typology of farmers; 2) to assess the goal of their enterprise (sale or home consumption), and 3) to classify the farmers on their socioeconomic profile and guinea fowl farming system. The sampling was conducted following a snowball type design (chain referral sampling method), a non-probabilistic method where farmers were selected not from a sampling framework but from a friendship network of the farmers already part of the sample. Guinea fowl production was undertaken by persons from all social levels without distinctions due to education level. The majority of farmers were men with no formal education. They had less than 20 guinea fowl (31% of interviewed farmers) and practiced extensive farming. The majority (66%) of farmers of the survey focused on home consumption of egg and meat with sale of surplus. One of the major challenges for farmers is to control the mortality of young guinea fowl, which can be very high. The development of this breeding activity could contribute to food self-sufficiency in animal protein and contribute to the fight against poverty in Ivorian rural areas

This article belongs to the Special Issue Dietary Bioactives and Human Health; Around a quarter of the global adult population have metabolic syndrome (MetS) and therefore increased risk of cardiovascular mortality and diabetes. Docosahexaenoic acid, oat beta-glucan and grape anthocyanins have been shown to be effective in reducing MetS risk factors when administered as isolated compounds, but their effect when administered as bioactive-enriched foods has not been evaluated. OBJECTIVE: The overall aim of the PATHWAY-27 project was to evaluate the effectiveness of bioactive-enriched food consumption on improving risk factors of MetS. A pilot study was conducted to assess which of five bioactive combinations provided within three different food matrices (bakery, dairy or egg) were the most effective in adult volunteers. The trial also evaluated the feasibility of production, consumer acceptability and gastrointestinal tolerance of the bioactive-enriched food. METHOD: The study included three monocentric, parallel-arm, double-blind, randomised, dietary intervention trials without a placebo. Each recruiting centre tested the five bioactive combinations within a single food matrix. RESULTS: The study was completed by 167 participants (74 male, 93 female). The results indicated that specific bioactive/matrix combinations have effects on serum triglyceride or HDL-cholesterol level without adverse effects. CONCLUSION: The study evidenced that bioactive-enriched food offers a promising food-based strategy for MetS prevention, and highlighted the importance of conducting pilot studies.

International audience; For food preservation as well as for medical applications, because of increasing bacterial resistance towards antibiotics, novel and natural antimicrobial molecules are request. The widely studied lysozyme is a promising candidate to develop such molecules. This protein is well known and already used for its enzymatic activity against Gram-positive bacteria, but it also presents some activity against Gram-negative bacteria, supposedly due to its capability to disturb bacteria membrane. Otherwise, molecules that provoke bacterial membrane disruption are generally positively charged, amphipathic, and hydrophobic, all characteristics which can be modified. Especially, we previously showed that dry heating is a safe and easy process resulting in slight chemical modifications of lysozyme, with strong consequences regarding the charge, the hydrophobicity, and finally the interfacial properties of the protein. The question then arose: could lysozyme dry heating be an opportunity to create a new efficient antimicrobial? We actually demonstrated that the activity of dry heated lysozyme (DH-L) against Escherichia coli was higher than that of native lysozyme (N-L). Using optical microscopy and atomic force microscopy (AFM), strong morphological modifications of the bacteria were observed, consistently with the higher membrane permeabilization when E. coli cells were treated with DH-L: either larger pores or more pores in the outer membrane, as well as more ion channels in the cytoplasmic membrane were obtained with DH-L as compared to N-L. Using a lipopolysaccharide (LPS) monolayer and a phospholipid (PL) mixture monolayer as models of the E. coli outer and cytoplasmic membranes, respectively, the interaction between lysozyme and these monolayer models has been investigated by biophysics techniques such as tensiometry, ellipsometry, Brewster angle microscopy and AFM. We could thus established that dry heating increases lysozyme affinity for the model monolayers and its insertion capacity; the resulting reorganization of the model monolayers was also more drastic. Finally, using similar investigations with each of the lysozyme isoforms produced by dry heating, we could show that the most positive, flexible and hydrophobic isoform shows the highest antimicrobial activity. However, it is noticeable that the lysozyme isoforms mixture, I;e; DH-L was the most efficient against E. coli, suggesting synergetic cooperation between lysozyme isoforms.

Food allergy to egg is commonly diagnosed in childhood with good prognosis. Egg white (EW) is considered as the main culprit but egg yolk (EY) retained less attention and its clinical involvement remains unclear. Children with food allergy to egg were recruited and undergone skin prick-testing (SPT) with raw and hard-boiled EW and EY fractions, carefully prepared to avoid any cross-contamination. Specific IgE-binding towards EY in sera were determined by ELISA.Fifty-four children (15 girls; 3.8 ± 1.7 years old) were recruited. They mainly suffered from urticaria with both raw and cooked egg. All children had positive prick-tests to raw EW (mean diameter: 12.6 ± 7.0 mm) and 39 (72%) to raw EY; the mean of positive diameters was 8.8 ± 5.1 mm for EY. After hard-boiling, 36 (67 %) children still had positive SPT to EW and 15 to EY (28 % of the cohort, 38 % of children with positive SPT to raw EY) and means of positive diameters were 10.8 ± 5.6 mm for EW and 4.9 ± 2.1 mm for EY. Among egg yolk fractions, IgE in sera more frequently bound to lipovitellenins/LDL (36%) and livetins (34%) fractions than to lipovitellins/HDL (18%) and phosvitins (5%) fractions. Beside egg white, children with food allergy to egg appear to be more frequently sensitized to EY and reactive to raw and heated EY than generally assumed. Their IgE-reactivity to EY is mainly directed toward the plasma EY fraction.

Egg white is a hostile medium for microorganisms due to its harsh physicochemical properties (alkaline pH and high viscosity), the nutritional restriction it imposes and its arsenal of antimicrobial molecules that may interact with bacteria in a synergistic way. Salmonella enterica serovar Enteritidis is the major pathogen responsible for egg borne infection in humans, due to its exceptional capability for survival under the harsh conditions encountered within egg white. However, above 42 ˚C, egg white exerts a much stronger bactericidal effect on S. Enteritidis than at lower temperatures, without full understanding of the responsible mechanism. Here we describe the first global-transcriptional analysis of the response of S. Enteritidis to egg white exposure under bactericidal conditions, providing a unique insight into egg white antibacterial activity. In order to enable this study, we used an “egg white model medium” (EWMM) already shown to be an appropriate mimic of egg white. Incubation of S. Enteritidis in EWMM above 42°C provoked a major transcriptional response (18.7% of genes affected at 45 min), indicative of major changes of S. Enteritidis physiology. Cell and envelope damage/stress responses were induced (degradation of unfolded protein, maintenance of cell integrity, and translation shutdown), energy metabolism shifted from respiration to fermentation, and micronutrient provision was enhanced (related to iron and biotin restriction).Our investigation of the global expression response of S. Enteritidis to egg white provides a complete genome-wide view of the complex physiological response of this pathogen to egg white-induced bacterial destruction under specific conditions.

The microorganisms responsible for spoilage do not belong to a single taxonomic group. Bacteria, molds and yeasts can be the cause of alterations. The variety of food microorganisms depends on different factors. The first is relative to the nature of the food, for example, the fact that fish products may be contaminated by water, vegetables by soil and animal products by the intestinal tract of the animal from which the product is derived. The second factor relates to the intrinsic properties of the food, such as its chemical composition, pH, redox potential and/or water availability (estimated by water activity or wa). The third factor is related to the process of transformation and stabilization that the food product may have undergone. So, as it should be, the balance of the microorganisms can be modified by stabilization treatments (heat treatment, drying, acidification, addition of preservatives, cold storage or modified atmospheres or a combination of one or more of these treatments).

An egg product is a complex matrix, mainly composed of water, proteins and lipids. It also contains carbohydrates, vitamins, minerals and many other compounds in varying concentrations. This chemical complexity makes it difficult to analyze, and most of the protocols are mainly concerned with the albumen and vitellus fractions, aside from the whole egg product. The hygienic quality and freshness of eggs can be assessed according to physico-chemical or microbiological criteria, imposed by the regulations in force. The state provides procedures and recommendations for the production and marketing of such products. Criteria and procedures vary from region to region, for example European legislation forbids the breaking of eggs by centrifugation for eggs intended for the food industry whereas American legislation allows the possibility of breaking eggs by centrifugation if they are clean, disinfected and intact and if they ultimately undergo heat treatment (baking etc.). In addition to the procedures and recommendations concerning the production process, the hygienic quality of egg products is ensured by controlling the physico-chemical and microbiological quality of the raw materials used and the finished products. European legislation thus provides maximum levels for certain compounds such as lactic acid or succinic acid at different points in the production chain.

Ce numéro « Diversité des agricultures » est constitué d’articles issus des réflexions des groupes filières de l’Inra. Il brosse un panorama de la diversité agricole à l’œuvre dans les filières, en analyse les drivers et les déterminants, s’interroge sur la diversité comme source de résilience et en tire des enseignements en matière de besoins de recherche.; After a brief reminder of the structuring of the French poultry, egg and meat sectors, this documentmakes a statement of their diversity, with the objective of analyzing its contribution to the overallresilience of the sector. While the egg sector uses only one species, the hen, the meat sector relies on alarge diversity of species, even if broiler is the dominant production. The two sectors are marked by asignificant diversity of production methods, from intensive to alternative, and of end products, more orless transformed. In the egg sector, there is a tendency to replace conventional furnished cages socalled alternative systems, which are currently growing rapidly. In the meat sector, demand is strong forcut and processed products resulting from intensive production methods, a segment for which importsare important, but the demand of households for products raised under alternative conditions, withaccess to the outdoor area remains important. Organic production, still minority in poultry meat (1% in2016), is growing rapidly. In both sectors, the production is divided between highly organized sectorsand short circuits. The document then reflects on the strengths and weaknesses brought by thisdiversity to different levels of the sector and in different territories; Après un bref rappel de la structuration et de l’activité des filières avicoles françaises, ponte et chair, cedocument fait un état de leur diversité avec l’objectif d’analyser sa contribution à la résilience globale dela filière. Alors que la filière œuf utilise une seule espèce, la poule, la filière viande est marquée par ladiversité des espèces, même si le poulet de chair est la production dominante. Les deux filières sontmarquées par une diversité importante des modes de production, de l’intensif à l’alternatif, et desproduits qui en résultent, plus au moins transformés. En filière œuf, la tendance est au remplacementdes systèmes conventionnels en cages aménagées par des systèmes actuellement qualifiésd’alternatifs, actuellement en forte croissance. En filière chair, la demande est forte pour des produitsdécoupés et transformés issus des modes de production intensifs, segment sur lequel les importationssont importantes, mais la demande des ménages pour des produits élevés en conditions alternatives,avec accès au plein-air se maintient. La production bio encore minoritaire en chair (1 % en 2016) est enforte croissance. Dans les deux filières, la production se répartit entre des filières organisées fortementcontractualisées et des circuits courts. Le document réfléchit ensuite aux forces et faiblesses apportéespar cette diversité aux différents étages de la filière et dans les différents territoires.

Session IV. Gamete "Omics". Un poster présenté; International audience

International audience; Efficient screening methods are needed to control antibiotic residues in eggs. A microbiological kit (Explorer® 2.0 test (Zeu Inmunotech, Spain)) and an immunobiosensor kit (Microarray II (AM® II) on Evidence Investigator™ system (Randox, UK)) have been evaluated and validated for screening of antibiotic residues in eggs, according to the European decision EC/2002/657 and to the European guideline for the validation of screening methods. The e-reader™ system, a new automatic incubator/reading system, was coupled to the Explorer 2.0 test. The AM II kit can detect residues of six different families of antibiotics in different matrices including eggs. For both tests, a different liquid/liquid extraction of eggs had to be developed. Specificities of the Explorer 2.0 and AM II kit were equal to 8% and 0% respectively. The detection capabilities were determined for 19 antibiotics, with representatives from different families, for Explorer 2.0 and 12 antibiotics for the AM II kit. For the nine antibiotics having a maximum residue limit (MRL) in eggs, the detection capabilities CCβ of Explorer 2.0 were below the MRL for four antibiotics, equal to the MRL for two antibiotics and between 1 and 1.5 MRLs for the three remaining antibiotics (tetracyclines). For the antibiotics from other families, the detection capabilities were low for beta-lactams and sulfonamides and satisfactory for dihydrostreptomycin (DHS) and fluoroquinolones, which are usually difficult to detect with microbiological tests. The CCβ values of the AM II kit were much lower than the respective MRLs for three detected antibiotics (tetracycline, oxytetracycline, tylosin). Concerning the nine other antibiotics, the detection capabilities determined were low. The highest CCβ was obtained for streptomycin (100 µg kg–1).

L’œuf d’oiseau: une source naturelle d’agents anti-infectieux originaux . Journée thématique Biotechnocentre-Biodiversité et Innovations pour la santé et le bien-être

The aim of this study is to assess the impact of a change in animal production system, through Bleu-Blanc-Coeur(BBC) specifications, on the fatty acids daily intake of an average French menu. The BBC specifications requireto increase α-linolenic acid (ALA, C18: 3n-3) in animal feed to change the fatty acid composition of theproducts. A 15-day meal plan representative of average consumption for the French adult male population wasdeveloped. It includes animal products from standard production system (STD) or from a BBC productionsystem. The fatty acids intake of both diet was calculated. The results show that the modification of theproduction system allows a better conformity with the ANC (French dietary intake recommendations) in fattyacids. The effect is particularly important for n-3 polyunsaturated fatty acids for which the intake increases by80% for ALA (C18:3n-3) and by 35% for DHA (C22: 6n-3), thus reducing about 45% the deviations from ANCfor ALA and DHA. BBC eggs are the main product to DHA improvements since they contribute to 66% to thereduction of ANC deviations compared to the STD menu. For ALA, poultry meat and eggs from BBCspecifications are as important as pork meat with a contribution of 11% and 13%, respectively, to the reductionof the deviation from ANC.; L’objectif de cette étude est d’étudier l’effet d’un changement de mode de production des animaux, au traversdes cahiers des charges Bleu-Blanc-Coeur (BBC), sur les apports en acides gras journaliers d’un menu moyenfrançais, avec un focus particulier sur les produits avicoles. Les cahiers des charges BBC imposent des apportsminimum en acide α-linolénique (ALA, C18:3n-3) dans les rations animales, entrainant une modification de lacomposition en acides gras des produits. Un menu sur 15 jours représentatif de la consommation moyenne desfrançais a été développé à partir des données d’enquêtes alimentaires. Sur cette base, deux menus types ont étéconstruits : le premier menu (STD) comprend des produits animaux issus d’un mode de production standard ; lesecond substitue ces produits animaux standards par leurs équivalents issus de la filière BBC. Le bilan desapports en acides gras de ces deux menus est ensuite calculé. Les résultats montrent que l’enrichissement enoméga 3 des produits grâce à la modification du mode de production des animaux d’élevage permet unemeilleure adéquation vis-à-vis des apports nutritionnels conseillés (ANC) en acides gras. L’effet estparticulièrement visible pour les acides gras polyinsaturés n-3 pour lesquels les apports croissent de 80% pourl’ALA (C18:3n-3) et de 35% pour le DHA (acide docosahexaénoïque, C22:6n-3), réduisant ainsi d’environ 45%les écarts vis-à-vis des ANC pour l’ALA et le DHA. Les oeufs BBC sont les premiers vecteurs de l’améliorationdes apports en DHA puisqu’ils contribuent à 66% à la réduction des écarts aux ANC, comparativement au menuSTD. Les viandes de volaille et les oeufs BBC constituent un levier aussi important que la viande de porc avecdes contributions respectives de 11% et de 13% à la réduction des écarts aux ANC pour l’ALA.

Over the last decades, many studies have demonstrated the beneficial effects of Docosahexaenoic acid (DHA) on human health. Nevertheless, most of these studies have been performed using DHA as a purified compound rather than as an ingredient of real and complex food matrices. However, the DHA -food matrix interaction could deeply impact on its digestibility and bioaccessibility, and hence, on its bioavailability and effectiveness. The objective of this study was to determine to what extent the food matrix structure impacts the kinetics of DHA during digestion and its final bioavailability under in vivo conditions.Three different DHA-enriched egg products with exactly the same composition but different structure (mousse, omelet and hard-boiled egg) were given to 9 pigs fitted with a T-shaped cannula at duodenal level and a jugular venous catheter. After being fed with each food matrix, blood and duodenal effluents were collected over time. DHA content in plasma and duodenal effluents was measured by GC. Additionally, total and free NH2, the degree of proteolysis and pH evolution in the duodenal samples were also determined The results concluded that the structure of the food matrix had a clear impact on both the kinetics of digestion and the final bioavailability of DHA. The mousse appeared to have been digested significantly faster than the solid omelet and hard-boiled egg. In the two latter, even 7h 30 min after the ingestion, relatively high amounts of DHA were detectable in the duodenal effluents. Proteins had a similar behavior than DHA regarding gastric emptying. The mousse, probably because of its foamy-liquid structure, allowed an easier and faster access of pancreatic and gastric enzymes, leading to a higher degree of proteolysis than the solid matrices. Finally, the bioavailability of DHA was higher after the ingestion of the omelet than for the mousse and the eggs. Acknowledgements: The authors participate in the FP7 EU Project PATHWAY-27 “Pivotal Assessment of the Effects of Bioactives on the Health and Wellbeing, from Human Genome to Food Industry” (grant agreement no. 311876)

Food structure is an important factor in the nutritional quality of foods. With regard to dietary protein, it may have an impact on protein digestibility, proteolysis kinetics, gastric emptying and amino acid bioavailability, all with potential metabolic consequences. Egg white is an appropriate food model to investigate these issues, since very different structures and textures can be produced while keeping the chemical composition constant. Recently, we established that protein matrix structure impacts the extent of proteolysis and the nature ofthe peptides generated during in vitro digestion of egg white protein aggregates and gels. Our question here is “do such differences also exist in vivo, and do they have any biological consequences?” To address these questions, a smooth-rigid egg white gel, a granular-spongy gel and an intermediate gel were prepared. Each gel was fed to pigs (n=33) as a single meal, and gastric chyme samples were collected over a 6h-postprandial period in order to measure pH, proteolysis and particle size along digestion at 10 different stomach locations. Blood samples were also collected for plasma amino acid analyses.Acidification of the chyme started in the pylorus regin regardless of the type of gel, but acidification kinetics depended on the gel type, which suggested that gel structure impacts on HCl distribution in the chyme. In contrast, proteolysis commenced in the proximal region, consistent with the location of pepsinogen secretory cells. But from 1h-postprandial, proteolysis profiles greatly differed depending on the gels: the higher proteolysis was 2 observed in the pyloric region for the granular-spongy gel (acidity and proteolysis gradients were consistent), while maximum proteolysis was observed in the proximal region for the smooth-rigid and intermediate gels (acidity and proteolysis gradients were opposite), suggesting that pepsin diffusion profiles depend on the type of gel. Proteolysis kinetics weremore rapid with granular-spongy gel than with intermediate gel, while the smooth-rigid gel was the most resistant to proteolysis, which was consistent with the particle size observed during digestion. Finally, amino acid absorption was faster for the granular-spongy gel than for the two other gels.

Reproduction in Birds is characterized by internal fertilization and external development of an embryo in a telolecithal egg containing all nutrients, biological activities and protective systems required for the proper growth of the embryo, until hatch. This article will give an overview on the chicken ( Gallus gallus ) egg yolk proteins and vitellogenesis, knowing that the formation and structure of the egg (including the yolk) is quite conserved, regardless of the Bird species, although some differences exist in the timing and number of clutches of eggs produced, and in some specific egg traits (egg weight, yolk/white proportion, biochemical composition, etc.).

Pasteurised liquid egg products represent around 70% of total egg products. Pasteurisation, necessary for microbiological safety, is a unit operation undergone by the totality of liquid whole egg commercialized. The present work aims to investigate the impact of a wide range of pasteurisation rates (among those classically used in industry) on the interfacial properties, in vitro digestibility and antigenicity of whole egg proteins, in order to optimize the unit operation parameters to ensure all whole egg qualities. Pasteurisation from 4 to 10 min at 60 °C improved protein interfacial properties, in vitro digestibility and decreased ovomucoid antigenicity but did not significantly change ovotransferrin and lysozyme antigenicity. On the opposite, pasteurisation from 4 to 10 min at 66 °C decreased protein in vitro digestibility and increased drastically ovotransferrin antigenicity. Pasteurisation from 4 to 10 min at 60 °C enabled to reach all whole egg properties, but for safety reasons, higher pasteurisation rates at 62 or 64 °C are good compromises to ensure microbiological safety without excessively damaging the functional properties.

The overall concentration of hexabromocyclododecane (HBCDD) in eggs is low although abnormally high concentrations exceeding 3000 ng g −1 lw have been reported. In order to test whether these contaminations may originate from the ingestion of insulating materials in rearing buildings, a group of 55 hens raised in a collective cage was provided with a 64-g piece of extruded polystyrene (XPS, 2.59% HBCDD of which 75, 15 and 10% as α-, β- and γ-HBCDD, respectively). Hens entirely consumed the piece within 3 days, leading to a mean daily exposure of 4.7 mg HBCDD per kg body weight. Whole egg HBCDD concentration reached a maximum of 1037 ng HBCDD g −1 fresh weight (fw), recorded 2 days after the piece had disappeared, and decreased down to 86 ng g −1 fw within the 19 following days. In all these samples, HBCDD was made of 98.7 ± 0.7 and 1.3 ± 0.6% α- and β-HBCDD, respectively, and 0.1% γ-HBCDD when quantified; it was enriched in (−)α- and (+)β-HBCDD with enantiomeric fractions of 0.438 ± 0.009 and 0.579 ± 0.030, respectively. HBCDD was quantified in all the individual eggs collected the last day of experiment at concentrations ranging between 0.47 and 1361 ng g −1 fw, according to a lognormal distribution. The ingestion of XPS in degraded rearing buildings is thus a plausible cause of on-farm egg contamination by HBCDD which should be strictly avoided.

Phenotype variability depends on genetics and environmental factors. Improving farm animal performances relies on genetic variability, but the possible improvement of selection schemes taking into account nongenetic transgenerational inheritance has become a topic of choice. Indeed, the parental diet may influence the adult phenotype of the offspring, and more and more studies suggest that information acquired from environmental exposures may be transmitted across generations. In this review, we focus on nongenetic inheritance of diet effects in birds, either as parental effect, that is, “nutritional programming,” or through the transmission of information across several generations, via “transgenerational epigenetic inheritance.” Compared to mammal models with regard to their closer proximity with humans, bird models have the added benefit to minimize maternal confounding effects by a direct manipulation of the egg content.

This chapter focuses on protein-based and lipid-based native nanostructures. The naturally occurring nanostructures coming from milk and eggs constitute a large part of the building blocks already used to design new nanostructures. The chapter also focuses on the description of the structure of several food proteins as they exist naturally in food. Food proteins exist mainly in the monomeric form, but are able to self-assemble into oligomers or aggregates in some specific conditions. These conditions are also addressed. The lipid droplets are spherical particles constituted by a hydrophobic core rich in triacylglycerols (TAG) covered by surfaceactive molecules such as phospholipids and proteins. These TAG-rich droplets are involved in the storage and delivery of energy. Milk fat globules have a core of TAG covered by a biological membrane composed by a trilayer of phospholipids and proteins.

Understanding the natural antibacterial defences of egg white and their regulation

A quoi reconnaît-on un oeuf frais ? L'oeuf est-il un aliment gras ? Comment la poule fait-elle son oeuf ? L'oeuf en poudre est-il encore de l'oeuf ? A quoi correspondent les codes sur les oeufs du commerce ? Cet ouvrage nous décrit l'ensemble de la filière oeufs, de l'élevage des poules au produit consommé dans nos assiettes. Il fait le point sur la biologie et la physiologie des oeufs, leurs qualités nutritionnelles, leur production industrielle et leur transformation en ovoproduits ou pour des usages non alimentaires. Tout en nous donnant des conseils de stockage, de consommation, et même d'élevage pour ceux qui rêvent d'un poulailler, il démystifie au passage certains croyances erronées sur l'oeuf.

Coproduits de la filière œuf : source de molécules d’intérêt pour l’Industrie Agroalimentaire comme des alternatives aux conservateurs. Journée thématique du Cluster Food Val de Loire

La poule aux oeufs d'or. Village des sciences - INRA Nouzilly

International audience; In mammalian species, including human, fertilization is characterized by the triggering of long-lasting calcium (Ca(2+)) oscillations in the egg cytoplasm. The monitoring of these Ca(2+) oscillations is a valuable technique to demonstrate that fertilization has occurred, to study egg activation events elicited downstream of the Ca(2+) signal, as well as to evaluate sperm quality. This chapter describes our protocol to monitor sperm-induced Ca(2+) oscillations in mouse eggs, using fluorescence microscopy techniques and the Fura-2-AM ratiometric Ca(2+) indicator.

MUSE Medicinal USe of Eggs. 1. Journées du GDR MuFoPAM « MultiFonction des Peptides antimicrobiens »

In this study, we assessed whether prenatal exposure to elevated yolk steroid hormones can influence in ovo chemosensory learning and the behavior of domestic chicks. We simulated a maternal environmental challenge by experimentally enhancing yolk progesterone, testosterone, and estradiol concentrations in hen eggs prior to incubation. The embryos from these hormones-treated eggs (HO) as well as sham embryos (O) that had received the vehicle-only were exposed to the odor of fish oil (menhaden) between embryonic Days 11 and 20. An additional group of control embryos (C) was not exposed to the odor. All chicks were tested following hatching for their feeding preferences between foods that were or were not odorized with the menhaden odor. In the 3-min choice tests, the behavior of O chicks differed significantly according to the type of food whereas C and HO chicks showed no preference between odorized and non-odorized food. Our result suggests weaker response in HO chicks. In addition, HO chicks showed impaired growth and reduced intake of an unfamiliar food on the 24-h time scale compared to controls. Our data suggest that embryonic exposure to increased yolk hormone levels can alter growth, chemosensory learning, and the development of feeding behaviors.

Résumé de la communication présentée lors du 42ème Congrès de l'AFSTAL en octobre 2016 à Nantes; Volailles axéniques : des modèles originaux pour l'étude du microbiote

Il est essentiel de trouver un équilibre entre la production d’aliments riches en nutriments et la préservation de l’environnement. Dans une perspective d’amélioration de la durabilité de notre système alimentaire, via potentiellement une plus grande place accordée à l’oeuf et aux ovoproduits, cette étude bibliographique vise à faire le point sur les performances environnementales effectives de la production d’oeufs et d’ovoproduits. Nous montrons dans cet article, sur la base des données disponibles dans la littérature, que la production de protéines d’oeufs entraine un faible impact sur l’occupation des terres, l’utilisation d’énergies non renouvelables et le changement climatique en comparaison d’autres productions animales. Les étapes de transformation desoeufs en oeufs coquilles emballés, ou en ovoproduits de type oeuf entier liquide pasteurisé, contribuent quant à elles de manière marginale aux émissions de gaz à effet de serre.

The impact of egg white gel (EWG) structure on the process of digestion was investigated using an in vitro digestion model and a multi-scale characterization of the EWG structure. Four different structures of EWG were prepared combining various pH and ionic strength conditions before heating. The extent of digestion, estimated by the appearance of soluble peptides, was greater for the particulate gel comprising spherical aggregates as compared to the filamentous gel comprising linear aggregates. This result may be explained by an alteration of enzyme diffusion due to the microstructural characteristics of the gel, or an alteration of digestive enzyme adsorption or catalytic activity due to local differences in pH within the gel matrices. Peptide identification using LC-MS/MS highlighted that the aggregate morphology modulated ovotransferrin hydrolysis which resulted in the release of specific peptides depending on the EWG structure. This work illustrates the links existing between two multi-step processes, protein structuration into gel matrices and matrix destructuration by digestive enzymes. Such quantitative and qualitative differences reinforce the importance of the food matrix on the digestibility of food and its subsequent nutritional quality.

Livrable 2.1-Rapport sur la purification de 7 protéines et peptides de l’œuf

Considering the quality of its proteins and lipids, and its vitamins and minerals content, egg is a qualitative food. But in France, the average consumption of eggs is low: between 20 to 30 g/day/person, i.e. 3 to 4 eggs per week. Despite its high nutritional density, egg then provides a low part of the nutrients actually consumed by the population (2 to 3%), except vitamin D (≈10%). Consumer surveys show that, even highly unjustified, health consideration (cholesterol content) still bridles egg consumption. Actually, nutritional studies show that an increased egg consumption does not increase cardiovascular risk, up to 1 egg per day at least. Moreover, many studies demonstrated that the nutritional profile of egg can be easily modified; this could also increase the contribution of eggs in the dietary intakes, and this for many different nutrients. Combined with its low environmental impact, the nutritional qualities of egg could make this food a part of the solution for a more sustainable food system.; Par la qualité de ses protéines et lipides, et sa densité en vitamines et minéraux, l’œuf est un aliment de choix. Mais la consommation moyenne d’œuf en France est faible : entre 20 et 30 g/jour/personne, soit 3 à 4 œufs par semaine. Malgré sa forte densité nutritionnelle, l’œuf ne contribue donc que modestement aux apports nutritionnels observés (2 à 3 %), à l’exception de la vitamine D (≈10 %). Les enquêtes auprès des consommateurs montrent que, bien que largement infondé, l’argument santé « teneur en cholestérol » freine encore la consommation d’œufs. En réalité, une consommation d’œuf accrue n’augmente pas le risque cardiovasculaire, jusqu’à un œuf par jour au moins. Par ailleurs, de nombreuses études ont montré les possibilités de modulation du profil nutritionnel de l’œuf, ce qui permettrait également d’augmenter la part des œufs dans les apports nutritionnels observés, et ce pour plusieurs nutriments. Associées à son faible impact environnemental, les qualités nutritionnelles de l’œuf pourraient faire de cet aliment l’une des clefs d’un système alimentaire plus durable.

Egg product quality is very important to the egg industry. White and yolk are respectively used for their foaming and emulsifying properties and depend on the quality of white-yolk separation. The yolk is surrounded by the vitelline membrane and the changes that occur in eggs during storage affect it. Thanks to a statistical analysis of a database, several factors affecting the membrane were studied. Vitelline membrane is affected by storage and its strength starts to decrease from five days. Age hen clearly has an impact on vitelline membrane: hens from 18 to 35 weeks must be used to guarantee a better separation. Temperature was studied by two ways: season and storage temperature. In each case temperature has a significant impact: cool temperature keep the membrane stronger. Hen strain has a lower impact but analysis show a statistical difference between white and brown strains. What’s more, white strains have a lower feed conversion ratio and produce eggs with a better albumen quality. Supplementation of hen diets with vitamin E (50UI/kg) was investigated. Isa Brown laying hens were housed in enriched colony cage. Two housings with 75 000 hens in each, were used to have a control and a supplemented group: no differences were found between control and supplemented group. Vitelline membrane can be affected by many factors: cool temperature, less than 5 days of storage and young white strain are the main factors that egg industry should respect to obtain the best quality of white-yolk separation.; L’industrie des ovoproduits cherche avant tout à fournir des produits conformes à la demande de leurs clients. La séparation du blanc et du jaune est pour la plupart du temps imparfaite : la membrane vitelline entourant le jaune se rompt et contamine le blanc, affectant ainsi ses propriétés foisonnantes. L’analyse statistique d’une base de données a permis d’étudier différents facteurs affectant la membrane vitelline. La force de rupture diminue avec la durée du stockage à partir du cinquième jour. Pour une meilleure séparabilité, il est conseillé d’utiliser les œufs de poules âgées entre 18 et 35 semaines. Le facteur température, à coupler avec le stockage, est également très important : ne pas dépasser les 15°C permet de conserver l’intégrité de la membrane vitelline plus longtemps. L’effet souche est bien moins important, mais les analyses montrent une différence significative entre souches blanches et brunes. De plus, les souches blanches ont un indice de consommation plus faible et produisent des œufs ayant une meilleure qualité d’albumen.Un régime enrichi en vitamine E (50UI/kg) a également été testé. L’élevage test a été choisi pour la présence de deux bâtiments identiques, accueillant 75 000 poules chacun, de même souche Isa Brown et de même âge : aucune différence significative n’a été trouvée entre le lot essai et témoin.De nombreux facteurs sont susceptibles d’affecter la membrane vitelline : basse température, moins de 5 jours de stockage et jeune souche blanche sont les principaux facteurs que devraient suivre les industriels pour obtenir des produits correspondants à leurs objectifs.