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International audience; Adaptation to heat exposure is required to maintain animal welfare and productivity under high ambient temperature (AT) conditions. In this study we investigate the effects of chronic heat exposure (5 weeks at a constant temperature of 32°C) on the liver and whole blood transcriptome of brown egg layers from 2 divergent lines selected for low (R-) and high (R+) residual feed intake. The R+ and R- hens were equally distributed among 2 temperature-controlled chambers and reared under thermo-neutrality (22°C). At 28 wk of age the AT of one chamber was increased to 32°C until 33 wk of age, when 32 animals (8 per line and treatment) were slaughtered. Total RNA was obtained from the liver and blood and was sequenced using the Illumina HiSEqn 3000, yielding an average per sample of 90 million paired-end reads. The reads were mapped to the Gallus gallus-5 reference genome by STAR software and counted by RSEM software using the Ensembl V87 GTF annotation. Comparisons between the two AT groups were made using the edgeR-robust R/Bioconductor package. Patterns of AT-specific differential expression were largely shared by the two lines, and no evidence of temperature × line interactions were observed. In liver, a total of 229 differentially expressed genes (DEG) were identified (adjusted P-values < 0.05) with respectively 104 and 125 over and under expressed in the heat-exposed compared to the control group. In blood, 960 DEG were identified between the two AT groups with 479 and 481 over and under expressed. Most DEG were tissue specific, and only 18 genes were DE in both liver and blood. Ingenuity Pathway Analysis revealed that many of the DEG in liver were associated with amino acid and lipid metabolisms and energy production. Key genes involved in fatty acid β-oxidation, ketogenesis, cholesterol biosynthesis were under-expressed in the heat-exposed animals. In blood, many of the DEG were associated with cell related functions. Based on the DEG expression profile, down-regulation was observed for the PI3K/AKT, the VEGF and the PDGF signalling pathways involved in cell survival and growth, vasculogenesis and angiogenesis. Taken together, these results indicate a tissue-specific response to heat exposure.

The model shown in the current publication is based on an equation system developed in a previous publication (Carré et al., 2015). An equation (D) describing protein deposition as a function of protein intake is added to this previous system, in order to obtain a complete description of growth and feed intake depending on feed composition and genetic features of broilers. A calculation is conducted for lean and fat lines with various dietary protein contents. Lean and fat lines are distinguished through the equation expressing lipid deposition as a function of [protein/energy] ratio and protein efficiency, and through the equation (D). The model provides results that are typical of differences between lean and fat lines, with a higher dietary protein recommendation for lean than for fat line, lower feed conversion ratios (FCR) in lean than in fat line, and higher protein efficiencies in lean than in fat line.

Chicken muscle ribosomal protein S6 kinase (S6K1) has been recently characterised and its enzymic activity is regulated by the nutritional and hormonal (insulin) status in vivo. The regulation of S6K1 is still unknown in neonatal chicks. The present study aimed to compare the activation of S6K1 in early-feeding (EF) and 48 h-delayed-feeding (DF) chicks from hatching to 4 d of age. During post-hatching starvation, S6K1 activity remained at the basal level measured in the control-hatched chicks. The maximum S6K1 activity was recorded on the first day of feeding with an increase of about 2·5-fold in the EF and DF chicks (P

Broiler carcass quality can be improved by conventional selection techniques. In this regard, an experimental "quality" line (QL) was selected for high breast meat yield. We analyzed the effects of this selection on the dietary lysine requirement in chicks from 0 to 3 wk. Control (CL) and QL chicks were provided ad libitum access to isoenergetic diets containing 20% crude protein but differing in their lysine content (0.75, 0.88, 1.01, and 1.13%). Two-way ANOVA showed a significant effect (P0.01) of genotype on body weight, growth rate, feed intake, and weight of Pectoralis major and Gastrocnemius muscles. Conversely, the Sartorius muscle weight was not modified (P = 0.21) by genotype. Lysine deficiency markedly reduced body weight, growth rate, and feed intake, and increased feed conversion ratio (P0.001). Low dietary levels of lysine also depressed the weight of Gastrocnemius, Sartorius, and P. major (P0.001). The body or muscle weight response to diet lysine concentration depended on the line, with QL chicks appearing less sensitive to lysine deficiency. Consequently, their dietary requirements could be lower. Finally, when weight gain and P. major muscle protein deposition were plotted against lysine intake, QL chicks appeared to be more efficient than CL chicks. The underlying mechanisms responsible for this await clarification.

Chantier qualité GA; International audience; The mule duck, an interspecific hybrid obtained by crossing common duck (Anas platyrhynchos) females with Muscovy (Cairina moschata) drakes, is widely used for fatty liver production. The purpose of the present study was to detect and map single and pleiotropic QTL that segregate in the common duck species, and influence the expression of traits in their overfed mule duck offspring. To this end, we generated a common duck backcross (BC) population by crossing Kaiya and heavy Pekin experimental lines, which differ notably in regard to the BW and overfeeding ability of their mule progeny. The BC females were mated to Muscovy drakes and, on average, 4 male mule ducks hatched per BC female (1600 in total) and were measured for growth, metabolism during growth and the overfeeding period, overfeeding ability, and the quality of their breast meat and fatty liver. The phenotypic value of BC females was estimated for each trait by assigning to each female the mean value of the phenotypes of her offspring. Estimations allowed for variance, which depended on the number of male offspring per BC and the heritability of the trait considered. The genetic map used for QTL detection consisted of 91 microsatellite markers aggregated into 16 linkage groups (LG) covering a total of 778 cM. Twenty-two QTL were found to be significant at the 1% chromosome-wide threshold level using the single-trait detection option of the QTLMap software. Most of the QTL detected were related to the quality of breast meat and fatty liver: QTL for meat pH 20 min post mortem were mapped to LG4 (at the 1% genome-wide significance level), and QTL for meat lipid content and cooking losses were mapped to LG2a. The QTL related to fatty liver weight and liver protein and lipid content were for the most part detected on LG2c and LG9. Multitrait analysis highlighted the pleiotropic effects of QTL in these chromosome regions. Apart from the strong QTL for plasma triglyceride content at the end of the overfeeding period mapped to chromosome Z using single-trait analysis, all metabolic trait QTL were detected with the multitrait approach: the QTL mapped to LG14 and LG21 affected the plasma cholesterol and triglyceride contents, whereas the QTL mapped to LG2a seemed to impact glycemia and the basal plasma corticosterone content. A greater density genetic map will be needed to further fine map the QTL.

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International audience; 1. The current experiment is the second part of a study about the effects of wheat quality on digestibility of pelleted diets for broiler chickens. In the first part, it was previously shown that a hard cultivar resulted in a negative effect on starch digestibility in two divergent lines of chickens (D+ and D-) selected for digestion capacity. The aim of this second part was to investigate the reasons for this negative effect of a hard cultivar (Baltimor) compared to a soft one (Scipion) in D+ and D- lines. 2. Proventriculus pepsin activity, pancreas proteolytic and amylolytic activities were estimated in four pools of birds: "D+ line (Baltimor fed)", "D+ line (Scipion fed)", "D- line (Baltimor fed)" and "D- line (Scipion fed)". Results suggested greatest amount of pepsin units per g BW for D+ birds and lowest amount of pancreas proteolytic units per g BW for D+ birds fed Scipion wheat. Pancreas showed very similar α-amylase activities among treatments. 3. In vitro hydrolyses of wheat gluten proteins with proventriculus extracts from pools of D+ and D- birds did not show any differences between hard and soft cultivars, whatever the origin of pools. 4. Pepsin hydrolysis of fine (300 to 425 µm) and coarse (1180 to 1600 µm) fractions from wheat flours (Baltimor or Scipion) showed that the 30 min proteolysis rate was highest for the fine fraction in both cultivars. No difference was observed with extended hydrolysis time. 5. In vitro digestion simulation of whole wheat flours confirmed the results previously obtained in vivo, with a negative effect of hard cultivar on starch digestion rate, and no effect on protein digestion. 6. Laser particle size analyses showed that ileum digesta from birds fed with hard wheat cultivar showed highest proportion of coarse particles. 7. Microscopic analyses of D+ ileum digesta revealed that the concentration of undigested starch granules in subaleurone area of wheat bran particles was the highest with hard cultivar. 8. The results suggested that physical entrapment of starch granules in coarse particles was a major explanation for decreased starch digestibility values in chickens fed hard wheat diets.

International audience; The regulation of S6K1 by nutritional status and insulin has been recently reported in vivo in chicken muscle despite the relative insulin resistance of this tissue as estimated by phosphatidylinositol 3-kinase (PI3-kinase) activity. The present work aimed to study the impact of amino acids on S6K1 activity in quail muscle (QM7) myoblasts. Firstly, we characterized S6K1 in QM7 cells and demonstrated the absence of insulin receptors in these cells. Secondly, we showed that amino acids in the absence of insulin induced S6K1 phosphorylation on Thr389 and concomitantly increased its enzymatic activity. Amino acid-induced S6K1 activation was inhibited by LY294002 (PI3-kinase inhibitor) and rapamycin (inhibitor of the mammalian target of rapamycin, mTOR), suggesting the involvement of an avian homolog of mTOR. The availability of individual amino acids (methionine or leucine) regulated S6K1 phosphorylation on Thr389 and QM7 protein synthesis. In conclusion, amino acids regulate S6K1 phosphorylation and activity in QM7 cells through the mTOR/PI3-kinase pathway in an insulin-independent manner.

*INRA UMR Génétique Animale 35042 Rennes (FRA) Diffusion du document : INRA UMR Génétique Animale 35042 Rennes (FRA); National audience

International audience; Broiler chickens are characterized by fast muscle growth and high protein deposition, most likely subsequent to a high protein synthesis. However, the regulation of protein synthesis in chicken muscle is still unknown. In contrast, it has been clearly demonstrated in mammals that S6K1 is a key regulator of protein synthesis. In the present study, S6K1 was characterized in both pectoralis and gastrocnemius muscles in chickens. A 133-bp fragment of chicken S6K1 cDNA had 84% identity to mammalian S6K1. We investigated in vivo the effects of refeeding and insulin treatment after 16 h starvation. S6K1 enzyme activity was significantly increased in both pectoralis and gastrocnemius muscles by refeeding (two- to threefold greater than in food-deprived chickens, P < 0.05). Optimal activation occurred 30 min after refeeding following 16 h starvation. S6K1 activation was associated with its phosphorylation on serine and Thr 389 residues, which occurred within the first 5 min of refeeding. S6K1 was also significantly stimulated in both pectoralis and gastrocnemius muscles after a single insulin injection (nine- to 12-fold greater than in control chickens, P < 0.001). Our results indicate that S6K1 is expressed in chickens muscles and activated by refeeding and insulin treatment.

Cette synthèse présente l’influence des caractéristiques des animaux et de leurs conditions d’élevage sur les qualités des viandes et des chairs des principales espèces animales d’élevage (porc, bovins, ovins, poulets, poissons). Les dimensions intrinsèques (composition des carcasses, qualités sensorielle, nutritionnelle et technologique) et extrinsèques (interactions entre productions animales et environnement, bien-être des animaux, origine des produits, authenticité des pratiques de production…) de la qualité des produits sont considérées. Dans toutes les espèces, le type génétique et la conduite alimentaire sont les principaux déterminants de la composition des carcasses. La nature de l’alimentation des animaux constitue le principal levier pour moduler la qualité nutritionnelle, toutefois le niveau d’enrichissement des viandes et chairs en acides gras, minéraux ou vitamines favorables à la santé humaine varie selon les espèces. Pour une espèce donnée, les caractéristiques des animaux, leurs conditions d’élevage et d’abattage interagissent pour déterminer les propriétés (teneurs en lipides, glycogène, myoglobine…) et le métabolisme péri et post-mortem des muscles, et consécutivement la qualité sensorielle des viandes ou chairs et de leurs produits. A l’inverse, la qualité technologique, composante importante dans les filières porc, poulet et poisson résulte essentiellement du type génétique et des conditions d’abattage des animaux et de transformation des viandes. Dans les différentes filières animales, les qualités extrinsèques des produits font partie intégrante de certaines démarches collectives ou privées et sont garanties aux consommateurs au travers des signes officiels de qualité. Elles visent à améliorer les interactions favorables entre les productions animales et l’environnement et/ou le bien-être des animaux, garantir l’origine des produits et/ou valoriser l’authenticité des méthodes de production et de transformation. Différents exemples sont développés pour illustrer la prise en compte par les acteurs des filières de cette demande croissante des consommateurs et plus largement des citoyens envers leur alimentation., This review describes the influences of the characteristics of animals and their rearing conditions on the quality of meat and flesh in the main livestock species (pig, cattle, sheep, poultry, fish). Both the intrinsic (carcass composition and sensory, nutritional and technological qualities) and extrinsic (interactions between animal production and the environment, animal welfare, origin of products, authenticity of production practices…) dimensions of quality of meat and flesh products are considered. In all animal species, the genotype and feeding practices are the main factors determining carcass composition. Feed composition is the main factor modulating nutritional quality, even though the enrichment level of meat or flesh with fatty acids, minerals or vitamins favorable for human health depends on the species considered. Within species, interactions between the characteristics of animals and their rearing and slaughtering conditions determine the properties (intramuscular fat, glycogen, myoglobin contents…) and peri and postmortem metabolism of muscles and, consequently, the sensory quality of meat or flesh and their products. Conversely, the technological quality of meat, which is important especially for pig, poultry and fish mainly results from the animal genotype and the slaughtering and processing techniques. In all meat animal chains, some productions are differentiated on claims on extrinsic qualities of products and are guaranteed to consumers by official quality schemes. They aim at improving the positive interactions between animal production and environment and/or animal welfare, or guaranteeing products origin or authenticity of production and processing methods. Some examples are described to underline the awareness of meat chain actors about the increasing demand from consumers and more generally citizens towards their diet.

It has been previously established that growth and carcass qualities of chicks are modified by genotype and dietary amino acid supply. In this study, we evaluated the effects of lysine deficiency and genetic selection on muscle protein metabolism. Chicks originating from an experimental line selected for breast development (QL) and its control line (CL) were provided ad libitum access to isoenergetic diets containing 20% crude protein but differing in their lysine content (0.75 or 1.01%). Protein fractional synthesis rates (FSR) were measured in vivo in the pectoralis major and sartorius muscles of 3-wk-old chickens (flooding dose of [3H]phenylalanine). Fractional breakdown rates (FBR) were estimated as the difference between synthesis and deposition. Lysine deficiency reduced (P0.001) growth performance and muscle weights and increased (P0.05) muscle FSR, capacity for protein synthesis (muscle RNA:Protein, Cs) and FBR. Although QL birds grew faster and had heavier pectoralis major muscles than CL birds (P0.05), there was no line difference in sartorius weight (P = 0.15). No difference between the lines was observed in sartorius protein metabolism (P0.14). In the pectoralis major muscle, chicks of both lines receiving an adequate lysine intake also exhibited similar protein turnover rates. However, in chicks fed the lysine-deficient (0.75% lysine) diet, FSR and Cs were higher in QL than in CL chicks (P0.05), and FBR tended (P = 0.07) to be higher in QL chicks. This increased protein turnover in the QL birds on the lysine-deficient diet suggests that the responsiveness of muscle protein metabolism to amino acid supply is modified by genetic selection for breast development.

s communications; International audience

The main objective of this paper is to address the following question: are the containment measures imposed by most of the world governments effective and sufficient to stop the epidemic of COVID-19 beyond the lock-down period? In this paper, we propose a mathematical model which allows us to investigate and analyse this problem. We show by means of the reproductive number,${\cal R}_0$that the containment measures appear to have slowed the growth of the outbreak. Nevertheless, these measures remain only effective as long as a very large fraction of population,p, greater than the critical value$1-1/{\cal R}_0$remains confined. Using French current data, we give some simulation experiments with five scenarios including: (i) the validation of model withpestimated to 93%, (ii) the study of the effectiveness of containment measures, (iii) the study of the effectiveness of the large-scale testing, (iv) the study of the social distancing and wearing masks measures and (v) the study taking into account the combination of the large-scale test of detection of infected individuals and the social distancing with linear progressive easing of restrictions. The latter scenario was shown to be effective at overcoming the outbreak if the transmission rate decreases to 75% and the number of tests of detection is multiplied by three. We also noticed that if the measures studied in our five scenarios are taken separately then the second wave might occur at least as far as the parameter values remain unchanged.

Food product authentication encompasses several concepts. In this review, only aspects relating to the authentication of the origin and conditions of production, processing and preservation of poultry meat products will be discussed. So far, in response to the legislator’s request, technical efforts have focused on detecting adulteration of products, in particular the recognition of species. DNA-based techniques have proven to be highly effective, reliable and fast in meeting this need. They are now used routinely by control laboratories. In addition to the nutritional and health quality of products, consumers want to be reassured also about the geographical origin (local, national product, AOC, IGP) and the rearing conditions in particular those under official quality signs (Label Rouge, Organic). Research efforts must therefore be continued to develop techniques that are fast, reliable, easy to use and inexpensive to meet these new expectations.; L'assurance de l'authenticité des aliments et la détection de la falsification sont des questions critiques dans l'industrie alimentaire. Cet article a pour objet de faire le point sur les méthodes actuellement disponibles pour garantir l'authentification de l'origine et des conditions de production, de transformation et de conservation des produits carnés de volailles. Résumé : L'authentification des produits alimentaires regroupe plusieurs notions. Dans cet article, ne seront abordés que des aspects relatifs à l'authentification de l'origine et des conditions de production, de transformation et de conservation des produits carnés de volailles. Jusqu'à présent, pour répondre à la demande du législateur, les efforts techniques ont surtout porté sur la détection d'adultération des produits en particulier la reconnaissance d'espèces. Les techniques basées sur l'ADN se sont avérées très performantes, fiables et rapides pour répondre à ce besoin. Elles sont utilisées en routine à présent par les laboratoires de contrôle. Outre la qualité nutritionnelle et sanitaire des produits, les consommateurs souhaitent être rassurés aussi sur l'origine géographique (produit local, national, AOC, IGP) et les modes de production en particulier ceux sous signe officiel de qualité (Label Rouge, Bio). Les efforts de recherche doivent donc être poursuivis pour développer des techniques rapides, fiables, simples d'utilisation et peu coûteuses pour répondre à ces nouvelles attentes. Abstract: Authentication of the origin and conditions of production, processing and preservation of poultry meat products Food product authentication encompasses several concepts. In this review, only aspects relating to the authentication of the origin and conditions of production, processing and preservation of poultry meat products will be discussed. So far, in response to the legislator's request, technical efforts have focused on detecting adulteration of products, in particular the recognition of species. DNA-based techniques have proven to be highly effective, reliable and fast in meeting this need. They are now used routinely by control laboratories. In addition to the nutritional and health quality of products, consumers want to be reassured also about the geographical origin (local, national product, AOC, IGP) and the rearing conditions in particular those under official quality signs (Label Rouge, Organic). Research efforts must therefore be continued to develop techniques that are fast, reliable, easy to use and inexpensive to meet these new expectations. La revue scientifique

Summary Mammalian brain development critically depends on proper thyroid hormone signaling, via the TRα1 nuclear receptor. The downstream mechanisms by which TRα1 impacts brain development are currently unknown. In order to investigate these mechanisms, we used mouse genetics to induce the expression of a dominant-negative mutation of TRα1 specifically in GABAergic neurons, the main inhibitory neurons in the brain. This triggered post-natal epileptic seizures and a profound impairment of GABAergic neuron maturation in several brain regions. Analysis of the transcriptome and TRα1 cistrome in the striatum allowed us to identify a small set of genes, the transcription of which is upregulated by TRα1 in GABAergic neurons and which probably plays an important role during post-natal maturation of the brain. Thus, our results point to GABAergic neurons as direct targets of thyroid hormone during brain development and suggest that many defects seen in hypothyroid brains may be secondary to GABAergic neuron malfunction., Graphical Abstract, Highlights • GABAergic neurons are a direct target of thyroid hormone in the developing brain • Impaired TH/TRα1 signaling severely impairs the development of GABAergic neurons • GABAergic-specific genes directly targeted by TH/TRα1 signaling have been listed • A defect in the GABAergic system is expected in patients with a THRA mutation, Neuroscience; Molecular Neuroscience; Developmental Neuroscience

Discoffeery session pour professionnels porteurs d'enjeux; Towards biomarkers of feed efficiency Using –omics approaches for biomarkers discovery . Réunion finale du projet européen Feed-a-Gene

International audience; Hexabromocyclododecane (HBCD) is a critical emerging brominated flame retardant to which consumers can be exposed at high doses through a single food intake. Based on an animal experiment involving 3 groups of laying hens fed during 70 days with a control diet or gamma-HBCD-contaminated diets at 0.1 or 10mug gamma-HBCD g-1 feed, this study aims to use the volatolome of biological samples for revealing markers of livestock exposure to HBCD. Liquid chromatography-tandem mass spectrometry was used to monitor the time-course of HBCD levels in bodily samples. Each liver was analyzed by solid-phase microextraction-gas chromatography-mass spectrometry for volatolome profiling. After 70 days, gamma-HBCD concentrations in egg yolk, fat, liver and serum reached 54±4, 85±6, 31±6, and 32±4ngg-1 lw, respectively, for the low exposure level and 4.6+/5.7, 7.8+/6.5, 3.9+/3.0 and 3.9+/6.1mugg-1 lw, respectively, for the high exposure level. Isomerization of gamma-HBCD into alpha- and beta-HBCD was observed in all tissues, at least for the high exposure level. Volatolome data allowed a significant discrimination between control and exposed animals whatever the feed contamination load, demonstrating a liver metabolic response to gamma-HBCD exposure. The relevance of the twenty nine volatile exposure markers tentatively identified was discussed in light of literature data.

International audience; Thermal manipulation during embryogenesis was previously reported to decrease the occurrence of ascites and to potentially improve cold tolerance of broilers. The objective of our study was to explore the effects of the interaction of cold incubation temperatures and cool ambient temperatures until 21 d of age on performance and body temperature. Ross 308 eggs were incubated either under control conditions I-0 (37.6A degrees C) or with cyclic cold stimulations I-1 (6 h/d at 36.6A degrees C from d 10 to 18 of incubation) or with 2 cold stimulations I-2 (30 min at 15A degrees C) at d 18 and 19 of incubation. These treatments were followed by individual rearing and postnatal exposure to either standard rearing temperature T-0 (from 33A degrees C at hatching to 21A degrees C at d 21) or continuously lower temperature T-2 (from 28A degrees C at hatching to 21A degrees C at d 21) or exposure to cyclically lower temperature T-1 (with circadian temperature oscillations). Treatments I-1 and I-2 did not significantly alter hatchability compared to control incubation (with 94.8, 95.1, and 92.3%, respectively), or hatching BW and overall chick quality. Hatching body temperature (Tb) was 0.5 and 0.3A degrees C higher in I-1 than in I-0 and I-2 groups, respectively (P = 0.007). A doubled occurrence of health problems was observed with T-2 condition, regardless of incubation or sex. At d 3, BW was 2% lower with treatment I-1 than with I-0 and I-2 and was 3% higher in T-1 and T-2 groups than in T-0, but these effects disappeared with age. Group T-2 presented a 5% higher feed intake than the control group T-0 between 3 and 21 d of age (P = 0.025). Feed conversion ratio (FCR) was affected by experimental conditions (P < 0.001), with low FCR values obtained with I-2 incubation in control or cyclically cold postnatal conditions. Maximal FCR values were observed in the continuously cold postnatal conditions, in males submitted to control incubation and in females submitted to I-1 incubation, revealing sex-dependent effects of the treatments on performance.

Decades of intensive genetic selection in the domestic chicken (Gallus gallus domesticus) have enabled the remarkable rapid growth of today's broiler (meat-type) chickens. However, this enhanced growth rate was accompanied by several unfavorable traits (i.e., increased visceral fatness, leg weakness, and disorders of metabolism and reproduction). The present descriptive analysis of the abdominal fat transcriptome aimed to identify functional genes and biological pathways that likely contribute to an extreme difference in visceral fatness of divergently selected broiler chickens., We used the Del-Mar 14 K Chicken Integrated Systems microarray to take time-course snapshots of global gene transcription in abdominal fat of juvenile [1-11 weeks of age (wk)] chickens divergently selected on bodyweight at two ages (8 and 36 wk). Further, a RNA sequencing analysis was completed on the same abdominal fat samples taken from high-growth (HG) and low-growth (LG) cockerels at 7 wk, the age with the greatest divergence in body weight (3.2-fold) and visceral fatness (19.6-fold)., Time-course microarray analysis revealed 312 differentially expressed genes (FDR ≤ 0.05) as the main effect of genotype (HG versus LG), 718 genes in the interaction of age and genotype, and 2918 genes as the main effect of age. The RNA sequencing analysis identified 2410 differentially expressed genes in abdominal fat of HG versus LG chickens at 7 wk. The HG chickens are fatter and over-express numerous genes that support higher rates of visceral adipogenesis and lipogenesis. In abdominal fat of LG chickens, we found higher expression of many genes involved in hemostasis, energy catabolism and endocrine signaling, which likely contribute to their leaner phenotype and slower growth. Many transcription factors and their direct target genes identified in HG and LG chickens could be involved in their divergence in adiposity and growth rate., The present analyses of the visceral fat transcriptome in chickens divergently selected for a large difference in growth rate and abdominal fatness clearly demonstrate that abdominal fat is a very dynamic metabolic and endocrine organ in the chicken. The HG chickens overexpress many transcription factors and their direct target genes, which should enhance in situ lipogenesis and ultimately adiposity. Our observation of enhanced expression of hemostasis and endocrine-signaling genes in diminished abdominal fat of LG cockerels provides insight into genetic mechanisms involved in divergence of abdominal fatness and somatic growth in avian and perhaps mammalian species, including humans.

The objective of this ring test was to investigate the prececal phosphorus (P) digestibility of soybean meal (SBM) in broiler chickens using the trial protocol proposed by the World's Poultry Science Association. It was hypothesized that prececal P digestibility of SBM determined in the collaborating stations is similar. Three diets with different inclusion levels of SBM were mixed in a feed mill specialized in experimental diets and transported to 17 collaborating stations. Broiler chicks were raised on commercial starter diets according to station-specific management routine. Then they were fed the experimental diets for a minimum of 5 d before content of the posterior half of the ileum was collected. A minimum of 6 experimental replicates per diet was used in each station. All diets and digesta samples were analyzed in the same laboratory. Diet, station, and their interaction significantly affected (P < 0.05) the prececal digestibility values of P and calcium of the diets. The prececal P digestibility of SBM was determined by linear regression and varied among stations from 19 to 51%, with significant differences among stations. In a subset of 4 stations, the prececal disappearance of myo- inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate)-P; InsP6-P) also was studied. The prececal InsP6-P disappearance correlated well with the prececal P digestibility. We hypothesized that factors influencing InsP6 hydrolysis were main contributors to the variation in prececal P digestibility among stations. These factors were probably related to the feeding and housing conditions (floor pens or cages) of the birds in the pre-experimental phase. Therefore, we suggest that the World's Poultry Science Association protocol for the determination of digestible P be should extended to the standardization of the pre-experimental period. We also suggest that comparisons of P digestibility measurements among studies are made only with great caution until the protocol is more refined. info:eu-repo/semantics/publishedVersion

Impact du stress oxydant sur les performances, la robustesse et la santé des animaux de rente et sur la qualité de leurs produits. Défis scientifiques Phase

L'accroissement de l'efficacité alimentaire est un élément clé de la durabilité économique et environnementaledes systèmes de productions animales. Cet accroissement peut être réalisé par l'application de technologiesinnovantes telles que l'alimentation de précision permise par les progrès en termes de capteurs et d'automates, et aussi d'outils d'aide à la décision (OAD). Dans le cadre du programme Horizon 2020 EU Feed-a-Gene , un OAD a été développé chez le porc et la volaille pour gérer les données et appliquer des modèles nutritionnels afin de il calculer en temps réel les besoins des animaux et ii) d'ajuster la composition et les quantités d'aliment àdistribuer. Cet outil, destiné à être utilisé en élevage commercial pour des animaux nourris individuellement ou engroupe, présente une structure modulaire pour s'adapter à plusieurs dispositifs d'alimentation, d'espèces et destades de production (porc en croissance, truie en gestation ou lactation, poulet de chair, poule pondeuse). Lesmodules sont conçus pour réaliser les opérations de façon coopérative, incluant la gestion des donnéescaractérisées par des méta-données définies pour l'alimentation de précision. L'outil permet une interopérabilitédes données entre les différents équipements (mangeoires, pesons .. . ), grâce à un encodage standard. Lesmodules sont dédiés à la vérification et la correction des données pour renseigner la base de données, laprédiction des performances (poids vif, consommation), le calcul des besoins nutritionnels et l'ajustement de laration. Des méthodes spécifiques d'analyse dynamique des données ont été testées et sélectionnées par espèce selon le nombre de données disponibles, le type de données et leur fréquence d'obtention. Le calcul des besoins nutritionnels est basé sur des modèles nutritionnels spécifiques à l'espèce ou au stade de production. Un travail a en particulier été réalisé chez la truie et le poulet de chair pour affiner les modèles existants. Les modules d'analyse et de prédiction sont actuellement conçus pour des animaux élevés en conditions optimales, mais pourront être étendus à des situations perturbées (pathologies, conditions climatiques inhabituelles) par l'ajout d'autres modèles. Pour le porc en croissance, I'OAD a été associé à des alimentateurs de précision en alimentation ad libitum ou rationnée pour des tests en élevage expérimental, avec une réduction observée de l'excrétion azotée de 7 à 10 o/o par rapport à une alimentation classique bi phase, sans modification des performances techniques. L'application de I'OAD chez le poulet de chair a permis une réduction du coût alimentaire (-5 %) et des rejets de phosphore (-6 %) malgré un indice de consommation légèrement supérieur (+0,03 point). Ces travaux montrent l'intérêt de ces OAD développés pour l'application de l'alimentation de précision afin d'améliorer simultanément la durabilité économique et environnementale des élevages de monogastriques.

This review is aimed at providing an overview of recent advances made in the field of meat quality prediction, particularly in Europe. The different methods used in research labs or by the production sectors for the development of equations and tools based on different types of biological (genomic or phenotypic) or physical (spectroscopy) markers are discussed. Through the various examples, it appears that although biological markers have been identified, quality parameters go through a complex determinism process. This makes the development of generic molecular tests even more difficult. However, in recent years, progress in the development of predictive tools has benefited from technological breakthroughs in genomics, proteomics, and metabolomics. Concerning spectroscopy, the most significant progress was achieved using near-infrared spectroscopy (NIRS) to predict the composition and nutritional value of meats. However, predicting the functional properties of meats using this method—mainly, the sensorial quality—is more difficult. Finally, the example of the MSA (Meat Standards Australia) phenotypic model, which predicts the eating quality of beef based on a combination of upstream and downstream data, is described. Its benefit for the beef industry has been extensively demonstrated in Australia, and its generic performance has already been proven in several countries.

Intégration de caractères de résistance à cinq pathologies dans les schémas de sélection commerciale de truite, bar et daurade. 6 journées de la recherche filière

The Guinea fowl (Numidameleagris) presents a highly resistant eggshell compared to the other birds. We will described in this study the particular ultrastructure of the Guinea fowl shell that confers exceptional mechanical properties and how changes in organic matrix components controls the development of this structure. The inner part of the shell is similar to other birds, but an additional change in the size and orientation of crystals (switch) is observed at about 1/3 of the calcified layer. Large columnar calcite units break into smaller crystal units with varying crystallographic orientations forming a microstructure with an intricate interlacing of calcite crystals.We recently reported the Guinea fowl shell structural organization from the micro to the Angstrom, which underlined that this particular shell is a bilayer structure. Organic matrix is suspected to firstly induce the initial microstructure shift and then the secondary nucleation events resulting in smaller crystals with increasing misorientations. Consequently, the change of the intra-crystalline organic matter level during the crystal switch was also investigated. A proteomic survey allowed us to identify and characterize 149 proteins in Guinea fowl shell. These proteins were quantified at five calcification stages corresponding to the first events of mineral deposition, the growth of calcite units just prior the shift of crystal orientation, then to the period of the deposition of newly formed crystalline shape and to later stage when the growth of the newly formed crystals is stabilized after the microstructure shift and the secondary nucleation events. We have observed 61 matrix proteins only present in the shift period and potentially responsible of the change of mineral in the shell. Amongst them are calcium binding proteins (NPNT-X1, CALBP1, Protein S100-A6, ANXA1 and 2, CDH2…), core proteins of proteoglycans (TSKU, GPC4…), and other proteins regulating the activity of proteins driving the mineralization (SSP1, OC-116GDF6…). These proteins interact with mineral to produce changes in crystal size and orientation and consequently the new shell structure and its resulting mechanical properties. Data obtained will allow the determination of biological markers that will be used for the genomic selection of chicken layers with improved mechanical shell mechanical properties. Additionally, they provided a list of organic products that will be tested as additives for material and ceramics.

International audience; abstract simple

International audience; abstract simple

International audience; abstract simple

Effect of total substitution of soybean meal in a low-protein diet fed to finishing broilers. 22nd European Symposium on Poultry Nutrition

Pourquoi et comment évaluer les services rendus par les productions avicoles ?. 13èmes Journées de la Recherche Avicole et Palmipèdes à Foie Gras

La formulation bilinéaire permet de minimiser le coût alimentaire et les rejets en alimentation de précision. 13èmes Journées de la Recherche Avicole et Palmipèdes à Foie Gras

Modélisation de l’utilisation du phosphore alimentaire chez le poulet de chair. 13èmes Journées de la Recherche Avicole et Palmipèdes à Foie Gras

Effet de la substitution totale du soja dans un aliment à bas taux protéique chez le poulet de chair en finition. 13èmes Journées de la Recherche Avicole et Palmipèdes à Foie Gras

Résumé; Previous studies have shown that very early life events could have programming effects on adult physiology. Exposing poultry embryos to higher incubation temperatures improve their survival capacity to thermal challenge in adulthood. Recently, embryonic thermal manipulation (TM) has been shown to impact muscle development and hepatic metabolism in Pekin ducks. In this study, we aimed to test whether rising incubation temperature has an impact on development, growth and zootechnical performances in mule ducks, mainly used for fatty liver production. Different thermal incubation conditions were applied during embryogenesis on mule duck eggs with three TM groups and one control, for which the temperature was maintained stable throughout. A faster embryonic and growth development was observed for all TM groups. Significant changes in body temperature and body weight were measured at hatching time and throughout the breeding period. Finally, overfeeding induced significant increase of live body weight, leg muscle, fat, and liver weights in all groups, while embryonic TM significantly increased abdominal fat and liver weights compared to control overfed group.These results suggest that embryonic TM can improve fatty liver production in male mule ducks, nevertheless potential deleterious effects on eclosability need to be explored further.; Différentes études ont montré que des événements survenus très tôt dans la vie d’un animal pouvaient avoir des effets de « programmation » sur la physiologie de l’adulte. L'exposition d'embryons de volaille à des températures d'incubation élevées améliore leur capacité de survie lors de pics de chaleur à l'âge adulte.Récemment, il a été démontré que la manipulation thermique embryonnaire (MT) avait un impact sur le développement musculaire et le métabolisme hépatique chez les canards Pékin. Dans cette étude, notre objectif était de mesurer l’impact d’une élévation de la température d'incubation sur le développement, la croissance et les performances des canards mulards, principalement utilisés pour la production de foie gras.Nous avons testé trois modalités expérimentales d’augmentation de la température dans l’incubateur sur des embryons de canards mulards, parallèlement un groupe témoin était maintenu à température constante tout au long de l’embryogenèse. Une éclosion plus précoce a été observée pour tous les groupes soumis à une MT (1 jour d’avance en moyenne). Des changements significatifs de la température et du poids corporels ont été mesurés à l'éclosion et tout au long de l’élevage. Enfin, le gavage a entraîné une augmentation significative du poids vif , des muscles de la cuisse, du tissu adipeux et du foie dans tous les groupes traités, tandis qu’une MT embryonnaire augmentait de manière significative le poids de graisse abdominale (jusqu’à +13,3% ; P=0,0001)et du foie (jusqu’à +16,9% ; P

L’élevage est souvent perçu comme inefficient pour produire des denrées alimentaires pour l’Homme car les animaux consomment davantage de végétaux qu’ils ne produisent de viande, de lait ou d’œufs. Le calcul de l’efficience nette de conversion des aliments en ne considérant dans le calcul que la part potentiellement consommable par l’Homme des aliments utilisés par les animaux permet de relativiser ce constat. En effet, une large part des aliments consommés par les animaux d’élevage (fourrages, coproduits…) n’est pas directement consommable par l’Homme. Appliqués à des systèmes d’élevage français, les calculs d’efficience nette montrent que toutes les productions animales (bovins laitiers et à viande, ovins à viande, porcins, poulets de chair, poules pondeuse) peuvent être producteurs nets de protéines à condition de maximiser la part des végétaux non valorisables en alimentation humaine dans les rations. Le calcul de l’efficience nette est très sensible à l’estimation de la part des aliments utilisés en alimentation animale qui peut être directement valorisée par l’Homme. Celle-ci varie fortement d’une matière première à l’autre selon les habitudes alimentaires et les technologies agroalimentaire qui peuvent évoluer dans le temps. Il est donc nécessaire d’analyser les résultats d’efficience nette à travers plusieurs scénarios de valorisation des matières premières végétales. De même le niveau de valorisation du cinquième quartier de la carcasse des animaux d’élevage pour l’alimentation humaine est très variable et influence sensiblement les résultats d’efficience nette. Enfin, la prise en compte du différentiel de qualité entre les protéines végétales permettrait d’affiner les calculs d’efficience protéique., Livestock is often perceived as inefficient in producing food for humans because animals consume more plants than they produce meat, milk or eggs. The calculation of the net feed conversion efficiency by considering in the calculation only the potentially consumable part of the feed used by the animals makes it possible to relativize this observation. Indeed, a large part of the feed consumed by livestock (fodder, coproducts…) is not directly consumable by humans. Applied to French livestock systems, the net efficiency calculations show that all animal production (dairy and beef cattle, meat sheep, swine, broilers, layer hens) can be net producers of protein provided they maximize the use of non-edible feed for human in diets. The calculation of the net efficiency is very sensitive to the estimation of the part of the feed used in animals which can be directly valorized in human feeding. This part varies greatly from one feed to another depending on the food habits and agri-food technologies that can evolve over time. It is therefore necessary to analyze the results of net efficiency across several scenarios for valuing plant raw materials. Similarly, the level of valorisation of offals and byproducts of farm animals’ carcasses for human consumption is highly variable and significantly influences the net efficiency results. Finally, taking into account the difference in quality between plant and animal proteins would make it possible to refine protein net efficiency calculations.

International audience; A physiologically based pharmacokinetic (PBPK) model was developed to investigate the production-specific factors involved in the transfer of α-hexabromocyclododecane (α-HBCDD) to broiler meat. The model describes growth and lipid deposition in tissues of fast- (FG) and slow- (SG) growing broilers from hatching to slaughter and simulates the exposure through the ingestion of contaminated feed or expanded polystyrene insulation material. Growth parameters were obtained from the literature while parameters relative to uptake, distribution, and elimination of α-HBCDD were adjusted using results of a previous experiment involving broilers exposed through feed throughout the rearing period or allowed to depurate before slaughter. The model was used to compare the two main edible tissues, breast and leg meat, as well as skin, and to investigate the variability within strain. Between strains and within strain, α-HBCDD assimilation efficiency (AE) is higher when the animals are slaughtered young or heavy. However, increasing slaughter age will lower α-HBCDD concentration in tissues, due to dilution. Based on fresh weight, the concentration of α-HBCDD in breast muscles and skin tends to be lower in SG than in FG broilers (?30 to +10%), while it is 10% to 80% higher in leg muscles. Compared to breast muscles, consuming leg muscles would elicit an exposure 9 and 16 times higher in FG and SG broilers, respectively. The consumption of skin together with muscles would multiply the exposure by up to 36 times compared to breast muscle alone. In case of acute exposure, the α-HBCDD concentration in tissues increased sharply, all the more since the animals are lighter in weight, and then decreased rapidly. In FG broilers, dilution through growth contributed for up to 37%, 28% and 97% to the decontamination of breast muscles, leg muscles and skin, respectively, depending on the duration of depuration before slaughter.

Diet formulation has a direct impact on the efficiency of use of nutrient and energy by pigs and poultry and, consequently, it affects nutrient and waste flow at farm level. All the compounds found in the manure, or emitted into the air, originate from the fraction of the diet which is not retained by the animals. The improvement of efficiency of nutrient retention by pigs and poultry is an efficient way to reduce excretion and emission from the animals. Changing the composition of the feed is efficient to modify the chemical properties of excreta in order to reduce the gaseous emissions and the production of odours. Changing the composition if the feed may allow to better adapt the composition of excreta to their future use for biogas production or as fertilisers. Innovations in the development of enzymes and amino acid production have been and are still important levers for the development of low environmental impact feeding strategies for pigs and poultry. The development of feeding strategies for reducing N and P excretion by pigs and poultry requires a good knowledge of nutrient bioavailability in feed ingredients and a precise evaluation of requirements. Phase feeding is required for practical application of improved feeding strategies. It is facilitated by the use of computerised feeding systems with the perspective of precision feeding.

Animal studies have shown that very early life events may have programming effects on adult metabolism and health. In this study, we aim, for the first, time to elucidate the effects of embryonic thermal manipulation (TM) on the performance of overfed mule ducks, in particular for the production of foie gras (fatty liver). We designed three embryonic TMs with different protocols for increasing the incubation temperature during the second part of embryogenesis, to determine whether hepatic metabolism could be “programmed” to improve its fattening response to overfeeding at the age of three months. Initial results confirm that an increase in the incubation temperature leads to faster development (observed for all treated groups compared to the control group), and a decrease in the body surface temperature at birth. Thereafter, in a very innovative way, we showed that the three TM conditions specifically increased liver weights, as well as liver lipid content after overfeeding compared to the non-TM control group. These results demonstrate that embryonic TM effectively “programs” the metabolic response to the challenge of force-feeding, resulting in increased hepatic steatosis. Finally, our goal of improving foie gras production has been achieved with three different embryonic thermal stimuli, demonstrating the high reproducibility of the method. However, this repeatability was also perceptible in the adverse effects observed on two groups treated with exactly the same cumulative temperature rise leading to a reduction in hatchability (75 and 76% vs 82% in control), in addition to an increase in the melting rate after cooking. These results suggest that embryonic thermal programming could be an innovative and inexpensive technique for improving foie gras production, although the specific protocol (duration, level or period of temperature increase), remains to be elucidated in order to avoid adverse effects.

BackgroundProduction conditions of layer chicken can vary in terms of temperature or diet energy content compared to the controlled environment where pure-bred selection is undertaken. The aim of this study was to better understand the long-term effects of a 15%-energy depleted diet on egg-production, energy homeostasis and metabolism via a multi-tissue transcriptomic analysis. Study was designed to compare effects of the nutritional intervention in two layer chicken lines divergently selected for residual feed intake.ResultsChicken adapted to the diet in terms of production by significantly increasing their feed intake and decreasing their body weight and body fat composition, while their egg production was unchanged. No significant interaction was observed between diet and line for the production traits. The low energy diet had no effect on adipose tissue and liver transcriptomes. By contrast, the nutritional challenge affected the blood transcriptome and, more severely, the hypothalamus transcriptome which displayed 2700 differentially expressed genes. In this tissue, the low-energy diet lead to an over-expression of genes related to endocannabinoid signaling (CN1R,NAPE-PLD) and to the complement system, a part of the immune system, both known to regulate feed intake. Both mechanisms are associated to genes related polyunsaturated fatty acids synthesis (FADS1,ELOVL5andFADS2), like the arachidonic acid, a precursor of anandamide, a key endocannabinoid, and of prostaglandins, that mediate the regulatory effects of the complement system. A possible regulatory role ofNR1H3(aliasLXRα) has been associated to these transcriptional changes. The low-energy diet further affected brain plasticity-related genes involved in the cholesterol synthesis and in the synaptic activity, revealing a link between nutrition and brain plasticity. It upregulated genes related to protein synthesis, mitochondrial oxidative phosphorylation and fatty acid oxidation in the hypothalamus, suggesting reorganization in nutrient utilization and biological synthesis in this brain area.ConclusionsWe observed a complex transcriptome modulation in the hypothalamus of chicken in response to low-energy diet suggesting numerous changes in synaptic plasticity, endocannabinoid regulation, neurotransmission, lipid metabolism, mitochondrial activity and protein synthesis. This global transcriptomic reprogramming could explain the adaptive behavioral response (i.e. increase of feed intake) of the animals to the low-energy content of the diet.

Skeletal integrity in meat-type chickens is affected by many factors including rapid growth rate, nutrition and genetics. To investigate the genetic basis of bone and mineral metabolism, a QTL detection study was conducted in an intercross between two lines of meat-type chickens divergently selected for their high (D +) or low (D −) digestive efficiency. Tibia size (length, diameter, volume) and ash content were determined at 3 weeks of age as well as phosphorus (P) retention and plasma concentration. Heritability of these traits and their genetic correlations with digestive efficiency were estimated. A QTL mapping study was performed using 3379 SNP markers. Tibia size, weight, ash content and breaking strength were highly heritable (0.42 to 0.61). Relative tibia diameter and volume as well as P retention were strongly and positively genetically correlated with digestive efficiency (0.57 to 0.80). A total of 35 QTL were identified (9 for tibia weight, 13 for tibia size, 5 for bone strength, 5 for bone mineralization, 2 for plasma P concentration and 1 for P retention). Six QTL were genome-wide significant, and 3 QTL for tibia relative volume, weight and ash weight on chromosome 6 were fixed, the positive allele coming from the D-line. For two QTL for ash content on chromosome 18 and relative tibia length on chromosome 26, the confidence intervals were small enough to identify potential candidate genes. These findings support the evidence of multiple genetic loci controlling bone and mineral metabolism. The identification of candidate genes may provide new perspectives in the understanding of bone regulation, even beyond avian species., Highlight • The genetic basis of bone and mineral metabolism is investigated in a QTL detection study in meat-type chickens. • Thirty-five QTL were identified for tibia weight, size, strength and mineralization, plasma P concentration and P retention. • Six QTL were genome-wide significant. • Three QTL for tibia relative volume, weight and ash weight on chromosome 6 were fixed. • These findings support the evidence of multiple genetic loci controlling bone and mineral metabolism.

Intracellular cytoplasmic calcium ([Ca(2+) ]i ) has an important regulatory role in gamete functions. However, the biochemical components involved in Ca(2+) transport are still unknown in birds, an animal class that has lost functional sperm-specific CatSper channels. Here, we provide evidence for the presence and expression of various Ca(2+) channels in chicken sperm, including high voltage-activated channels (L and R types), the store-operated Ca(2+) channel (SOC) component Orai1, the transient receptor potential channel (TRPC1) and inositol-1,4,5-trisphosphate receptors (IP3 R1). L- and R-type channels were mainly localized in the acrosome and the midpiece, and T-type channels were not detected in chicken sperm. Orai1 was found in all compartments, but with a weak, diffuse signal in the flagellum. TRCP1 was mainly localized in the acrosome and the midpiece, but a weak diffuse signal was also observed in the nucleus and the flagellum. IP3 R1 was mainly detected in the nucleus. The L-type channel inhibitor nifedipine, the R-type channel inhibitor SNX-482 and the SOC inhibitors MRS-1845, 2-APB and YM-58483 decreased [Ca(2+) ]i sperm motility and acrosome reaction capability, with the SOC inhibitors inhibiting these functions most efficiently. Furthermore, we showed that Ca(2+) -mediated induction of AMP-activated protein kinase (AMPK) phosphorylation was blocked by SOC inhibition. Our identification of important regulators of Ca(2+) signaling in avian sperm suggests that SOCs play a predominant role in gamete function, whereas T-type channels may not be involved. In addition, Ca(2+) entry via SOCs appears to be the most likely pathway for AMPK activation and energy-requiring sperm functions such as motility and the acrosome reaction.

This review discusses the different duck species and their feeding management used in meat production in various countries. The initial review describes the requirements of meat type ducks for energy, proteins and amino acids and minerals, vitamins and trace-elements. Other areas discussed include recommendations regarding feed management (feed presentation, feed restriction, use of enzymes and feedstuffs, fatty acid composition of diets). The main breeds used for meat production in the world are Pekin, Muscovy and mule ducks. As growth rate, efficiency and body composition of these three genotypes are different, the specific features of each type of duck are examined when reared under intensive production systems.

Seaweeds are macroalgae, which generally reside in the littoral zone and can be of many different shapes, sizes, colours and composition. They include brown algae (Phaeophyceae), red algae (Rhodophyceae) and green algae (Chlorophyceae). Seaweeds have a long history of use as livestock feed. They have a highly variable composition, depending on the species, time of collection and habitat, and on external conditions such as water temperature, light intensity and nutrient concentration in water. They may contain non-protein nitrogen, resulting in an overestimation of their protein content, and nitrogen-to-protein conversion factors lower than 6.25, normally used for feed ingredients, have been advocated. They contain considerable amount of water. Most essential amino acids are deficient in seaweeds except the sulphur containing amino acids. Seaweeds concentrate minerals from seawater and contain 10–20 times the minerals of land plants. They contain only small amounts of lipids (1–5%), but majority of those lipids are polyunsaturated n-3 and n-6 fatty acids. Brown seaweeds have been more studied and are more exploited than other algae types for their use in animal feeding because of their large size and ease of harvesting. Brown algae are of lesser nutritional value than red and green algae, due to their lower protein content (up to approx. 14%) and higher mineral content; however brown algae contain a number of bioactive compounds. Red seaweeds are rich in crude protein (up to 50%) and green seaweeds also contain good protein content (up to 30%). Seaweeds contain a number of complex carbohydrates and polysaccharides. Brown algae contain alginates, sulphated fucose-containing polymers and laminarin; red algae contain agars, carrageenans, xylans, sulphated galactans and porphyrans; and green algae contain xylans and sulphated galactans. In ruminants, step-wise increase in the levels of seaweeds in the diet may enable rumen microbes to adapt and thus enhance energy availability from these complex carbohydrates. In monogastrics, those polysaccharides may impact the nutritional value but the addition of enzyme cocktails might help. In vivo studies on ruminants, pigs, poultry and rabbits reveal that some seaweeds have the potential to contribute to the protein and energy requirements of livestock, while others contain a number of bioactive compounds, which could be used as prebiotic for enhancing production and health status of both monogastric and ruminant livestock. Seaweeds tend to accumulate heavy metals (arsenic), iodine and other minerals, and feeding such seaweeds could deteriorate animal and human health. Regular monitoring of minerals in seaweeds would prevent toxic and other undesirable situations.

Two experiments were conducted to investigate the use of sorghum, cottonseed meal and millet in broiler diets and their interaction when they are used simultaneously. In Experiment 1, a corn-soybean meal control diet was compared with eight experimental treatments based on low tannin sorghum (S30, S45 and S60), cottonseed meal (CM15, CM40) or both ingredients included in the same diet (S30/CM40, S45/CM25 and S60CM15). Results showed that BW gain was not affected by the inclusion of sorghum or cottonseed meal. However, feed intake tended to be affected by the cereal type with the highest values with sorghum-based diets. Feed conversion ratio increased (P

L'introduction de graines oléo-protéagineuses locales dans l'alimentation des poules pondeuses améliorent la durabilité des élevages ainsi que la qualité de l'oeuf. 2. Rencontres Francophones sur les Légumineuses (RFL2)