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International audience; Chaque année, l’activité portuaire nécessite le draguage d’une importante quantité de sédiments marins qui finissent souvent stockés en décharge sous forme de déchets. Ces opérations sont coûteuses et néfastes pour l’environnement. Afin de minimiser ces rejets et d'optimiser les ressources dans une logique d'économie circulaire, cette étude vise à examiner la possibilité de valoriser des sédiments marins bruts sans aucun traitement pour le port de Pérols (PP) et après un pré-traitement par hydrocyclonage pour le port de Camargue (PC), ports situés sur la côte d’Occitanie en France. Cette valorisation consiste à substituer une partie du sable par ces sédiments fins bruts dans la formulation d’un béton ordinaire de classe XS2 C30/37. L’effet de la substitution du sable par 10, 20, 30, 40, 50% des sédiments de PC ou par 10, 15, 20 et 30% des sédiments de PP a été évalué. Les résultats montrent une diminution de la résistance mécanique avec l’augmentation du taux de substitution. Dans le cas des sédiments de PC, le pourcentage de substitution est limité à 40% si un béton de classe XS2 C30/37 est l’objectif. Pour des classes de béton inférieures, C20 à 25 par exemple, une substitution de sable par des sédiments à hauteur de 50% peut être envisagée. Dans le cas des sédiments de PP, La classe de béton maximale obtenue est C20 ou C25. Pour autant, il est possible de valoriser les fines de sédiments de dragages sans traitement coûteux économiquement ou environnementalement au sein de bétons destinés au milieu marin. Cette étude apporte donc des résultats préliminaires nécessaires à la valorisation durable des sédiments à moindre coût et à long terme.

International audience; Life cycle assessment, combined with bioeconomic models, can be used to assess environmental impacts (EI) and profits of production systems. Such models were developed on an individual performance trait basis to quantify the main EI (global warming potential - GWP, terrestrial acidification potential - AP, freshwater eutrophication potential - EP, and land occupation - LO) and the profit for scenarios that combined different genetic levels for feed efficiency, as a principal mechanism to reduce costs and excretion, and multiobjective formulation diets. First, nutritional requirements were obtained for each genetic line separately. Then, diets were optimised for the nutritional objectives and a least-cost (LC), least-EI (LE) or combined LC and LE (joint) objective. Performance records for 57 pigs per line fed a unique conventional diet were used to calibrate the individual pig nutritional profiles and estimate line nutritional requirements. Next, individual performances in response to the optimized diets were simulated. With the experimental conventional diet, the more efficient line had 7% lower EI and better profit (P 0.05) with their joint diets. The approach that was developed mitigated, due to the constraints applied to the diet formulation, the innate genetic disadvantages of the less efficient pigs at the economic and environmental levels. These approaches can be used to orientate strategic choices at the selection and management levels for more sustainable pig production.; Combiner génétique et nutrition pour une optimisation économique et environnementale en production porcine Les impacts environnementaux (IE) et les résultats économiques des systèmes de production peuvent être évalués par des analyses de cycle de vie couplées à des modèles bioéconomiques. De tels modèles ont été développés à partir des performances individuelles de porcs, pour quantifier les IE (potentiel de changement climatique-CC, d'acidification des sols-AP, d'eutrophisation des eaux-EP, occupation des sols-OS), et le résultat économique de scénarios combinant des génétiques différentes pour l'efficacité alimentaire-levier majeur de réduction des coûts et de la production d'effluents, et des formulations multi-objectifs des aliments. Après définition des besoins nutritionnels spécifiques de chaque génétique, des aliments dédiés ont été formulés à moindre coût (MC), à moindre impact environnemental (ME, poids équilibrés pour les 4 catégories), ou combinant ces deux critères (MEC). Les données génétiques (2x57 porcs de lignées divergentes pour l'efficacité alimentaire, performances individuelles obtenues avec un aliment conventionnel) ont permis d'estimer les besoins nutritionnels par lignée, puis de simuler des performances individuelles en réponse aux aliments optimisés. Avec le régime conventionnel initial, la lignée plus efficace avait-7 % d'IE et un meilleur profit (P < 0,001). Avec les aliments ME et MEC, l'avantage environnemental des animaux efficaces était réduit (4,91 % et 4,29 %), et l'aliment MEC permettait d'atteindre des profits similaires pour les deux lignées. Cette approche permet donc dans une certaine mesure de compenser, par l'ajustement sous contraintes des rations alimentaires, les désavantages génétiques des animaux les moins efficaces sur les plans économiques et environnementaux. Il est alors envisageable d'orienter des choix stratégiques de sélection et de conduite pour proposer une production porcine durable. Combining genetics and nutrition in economic and environmental optimization of pig production systems Life cycle assessment, combined with bioeconomic models, can be used to assess environmental impacts (EI) and profits of production systems. Such models were developed on an individual performance trait basis to quantify the main EI (global warming potential-GWP, terrestrial acidification potential-AP, freshwater eutrophication potential-EP, and land occupation-LO) and the profit for scenarios that combined different genetic levels for feed efficiency, as a principal mechanism to reduce costs and excretion, and multiobjective formulation diets. First, nutritional requirements were obtained for each genetic line separately. Then, diets were optimised for the nutritional objectives and a least-cost (LC), least-EI (LE) or combined LC and LE (joint) objective. Performance records for 57 pigs per line fed a unique conventional diet were used to calibrate the individual pig nutritional profiles and estimate line nutritional requirements. Next, individual performances in response to the optimized diets were simulated. With the experimental conventional diet, the more efficient line had 7% lower EI and better profit (P 0.05) with their joint diets. The approach that was developed mitigated, due to the constraints applied to the diet formulation, the innate genetic disadvantages of the less efficient pigs at the economic and environmental levels. These approaches can be used to orientate strategic choices at the selection and management levels for more sustainable pig production.

International audience; We evaluated the economic and environmental impacts of strategies that incorporated selection for pig feed:gain and dietary optimization based on a single or multiple objectives tailored to meet the population’s nutritional requirements, with the goal to optimize sustainable farm feed efficiency. The economic and environmental features of the strategy were evaluated using life cycle assessment (LCA) and bio-economic models. An individual trait-based LCA model was applied to evaluate global warming potential (GWP), terrestrial acidification potential (AP), freshwater eutrophication potential (EP), and land occupation (LO) of the combined genetics and nutrition optimization to produce 1kg of live pig weighing 120kg at the farm gate. A parametric individual trait-based bio-economic model was developed and applied to determine the cost breakdown, revenue and profit to be gained from a 120kg live pig at the farm gate. Applying the combined genetics and nutrition optimization, the individual performance traits of pigs from two genetic lines with contrasted levels of feed efficiency were simulated with InraPorc in response to diets formulated for least cost, least environmental impacts, or minimum combination of cost and environmental impacts objectives, and accounting for the nutritional requirements of each line. Significant differences in the environmental impacts (P < 0.0001) and profit (P < 0.05) between lines predicted the same reference diet showed that selection for feed efficiency (residual feed intake, RFI) in pigs improves pig production sustainability. When pig responses were simulated with their line optimized diets, except for EP, all the line environmental impacts were less (P < 0.05) than with the reference diet. The high correlations of feed conversion ratio (FCR) with the environmental impacts (> 0.82) and the profit (< -0.88) in both lines underline the importance of feed efficiency as a lever for the sustainability of pig production systems. Implementing combined genetics and nutrition optimization, the inherent profit and environmental differences between the genetic lines was predicted to be reduced from 23.4% with the reference diet to 7.6% with the diet optimized jointly for economic and environmental objectives (joint diet). Consequently, for increased pig sustainability, diet optimization for sustainability objectives should be applied to cover the specific nutritional requirements arising in the herd from the pigs’ genetic level.

International audience; Life cycle assessment, combined with bioeconomic models, can be used to assess environmental impacts (EI) and profits of production systems. Such models were developed on an individual performance trait basis to quantify the main EI (global warming potential - GWP, terrestrial acidification potential - AP, freshwater eutrophication potential - EP, and land occupation - LO) and the profit for scenarios that combined different genetic levels for feed efficiency, as a principal mechanism to reduce costs and excretion, and multiobjective formulation diets. First, nutritional requirements were obtained for each genetic line separately. Then, diets were optimised for the nutritional objectives and a least-cost (LC), least-EI (LE) or combined LC and LE (joint) objective. Performance records for 57 pigs per line fed a unique conventional diet were used to calibrate the individual pig nutritional profiles and estimate line nutritional requirements. Next, individual performances in response to the optimized diets were simulated. With the experimental conventional diet, the more efficient line had 7% lower EI and better profit (P 0.05) with their joint diets. The approach that was developed mitigated, due to the constraints applied to the diet formulation, the innate genetic disadvantages of the less efficient pigs at the economic and environmental levels. These approaches can be used to orientate strategic choices at the selection and management levels for more sustainable pig production.; Combiner génétique et nutrition pour une optimisation économique et environnementale en production porcine Les impacts environnementaux (IE) et les résultats économiques des systèmes de production peuvent être évalués par des analyses de cycle de vie couplées à des modèles bioéconomiques. De tels modèles ont été développés à partir des performances individuelles de porcs, pour quantifier les IE (potentiel de changement climatique-CC, d'acidification des sols-AP, d'eutrophisation des eaux-EP, occupation des sols-OS), et le résultat économique de scénarios combinant des génétiques différentes pour l'efficacité alimentaire-levier majeur de réduction des coûts et de la production d'effluents, et des formulations multi-objectifs des aliments. Après définition des besoins nutritionnels spécifiques de chaque génétique, des aliments dédiés ont été formulés à moindre coût (MC), à moindre impact environnemental (ME, poids équilibrés pour les 4 catégories), ou combinant ces deux critères (MEC). Les données génétiques (2x57 porcs de lignées divergentes pour l'efficacité alimentaire, performances individuelles obtenues avec un aliment conventionnel) ont permis d'estimer les besoins nutritionnels par lignée, puis de simuler des performances individuelles en réponse aux aliments optimisés. Avec le régime conventionnel initial, la lignée plus efficace avait-7 % d'IE et un meilleur profit (P < 0,001). Avec les aliments ME et MEC, l'avantage environnemental des animaux efficaces était réduit (4,91 % et 4,29 %), et l'aliment MEC permettait d'atteindre des profits similaires pour les deux lignées. Cette approche permet donc dans une certaine mesure de compenser, par l'ajustement sous contraintes des rations alimentaires, les désavantages génétiques des animaux les moins efficaces sur les plans économiques et environnementaux. Il est alors envisageable d'orienter des choix stratégiques de sélection et de conduite pour proposer une production porcine durable. Combining genetics and nutrition in economic and environmental optimization of pig production systems Life cycle assessment, combined with bioeconomic models, can be used to assess environmental impacts (EI) and profits of production systems. Such models were developed on an individual performance trait basis to quantify the main EI (global warming potential-GWP, terrestrial acidification potential-AP, freshwater eutrophication potential-EP, and land occupation-LO) and the profit for scenarios that combined different genetic levels for feed efficiency, as a principal mechanism to reduce costs and excretion, and multiobjective formulation diets. First, nutritional requirements were obtained for each genetic line separately. Then, diets were optimised for the nutritional objectives and a least-cost (LC), least-EI (LE) or combined LC and LE (joint) objective. Performance records for 57 pigs per line fed a unique conventional diet were used to calibrate the individual pig nutritional profiles and estimate line nutritional requirements. Next, individual performances in response to the optimized diets were simulated. With the experimental conventional diet, the more efficient line had 7% lower EI and better profit (P 0.05) with their joint diets. The approach that was developed mitigated, due to the constraints applied to the diet formulation, the innate genetic disadvantages of the less efficient pigs at the economic and environmental levels. These approaches can be used to orientate strategic choices at the selection and management levels for more sustainable pig production.

International audience

International audience; To appoint proper strategy for prospective feed efficient pig farming it is wise to shed light on ongoing selection scenarios. Selection based on residual feed intake (RFI) has been proposed to improve feed efficiency, and potentially reduce the environmental impacts accordingly. Data were collected for pigs from the 5th generation of lines divergently selected for RFI (low line, more efficient pigs, LRFI; high line, less efficient pigs HRFI). Individual records for daily feed intake, body weights and body composition were available for about 60 pigs per line. The averages of feed conversion ratio and daily feed intake in the LRFI pigs were 7% lower than the average of the HRFI pigs according to the records. To compare the effects of the difference in feed efficiency on environmental impacts, a parametric model for life cycle assessment (LCA) was developed based on the net energy fluxes. A nutritional growth pig tool, InraPorc® was integrated as a module into the model to embed the flexibility for change in feed, traits and housing conditions, along with simulating individual pig performance. The comparative LCA showed 6% lower environmental impacts for LRFI on average relative to HRFI, considering climate change (CC), acidification potential (AP), eutrophication potential (EP), land occupation (LO) and water depletion (WD). Impacts of CC, AP,EP, LO and WD for 1 kg live weight of pig as the functional unit were 2.61 kg CO2-eq, 44.8 g SO2-eq, 3.37 g PO4-eq, 4.208 m3, 0.0448 m3 for LRFI, and 2.76 kg CO2-eq, 48 g SO2-eq, 3.62 g PO4-eq, 4.44 m3, 0.047 m3 for HRFI,respectively. Parallel Monte Carlo simulation on input parameters demonstrated that LRFI pigs would have a lower environmental impact than HRFI pigs in more than 70% of the calculations, except for water depletion (55% of the calculations). A once-at-a-time sensitivity analysis revealed that environmental impacts are highly sensitive toprotein content of the body and protein deposition. This correspondence between improvement of feed efficiencyand reduction of environmental impacts is very promising for prospective sustainable breeding objectives.