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International audience; Although pelleting of diets is a common practice in the pig industry, nutritional values are estimated from values of feedstuffs that have often been measured for diets presented as meal. The objectives of the study were to determine effects of pelleting at a low or a high temperature (55 or 78°C at the end of the conditioner) on digestive and metabolic utilization of nitrogen and energy of diets formulated with feedstuffs differing in their response to pelleting. During the experiment, nitrogen and energy balances of 48 pigs (24 castrated males and 24 females; mean body weight: 86 kg) were measured in respiration chambers when fed two diets offered as meal or pellets produced at a low or a high temperature. Digestive utilization of nitrogen and energy was improved by pelleting (+4.0 and 2.6 points increase in digestibility coefficient, respectively), regardless of the composition of the diet. Pelleting also improved the intake of metabolizable energy (+165 kJ/kg BW0.60/d) and energy retention (+150 kJ/kg BW0.60/d), because ofincreased energy efficiency and decreased heat production associated with physical activity. Castrated males always exhibited even better reactions to pelleting than females. Pelleting at a low temperature increased dietary net energy content by 5%, while increasing pelleting temperature reduced this improvement to 2.8%.; La granulation des aliments est un procédé fréquemment employé en alimentation porcine, même si les valeurs nutritionnelles sont le plus souvent estimées à partir d’aliments présentés sous forme de farine. L’objectif de l’expérimentation était de tester les effets induits par la granulation à deux températures différentes sur l’utilisation digestive et métabolique de l’azote et de l’énergie de deux aliments formulés à partir de matières premières se différenciant par leur comportement à la granulation, chez les porcs mâles castrés et femelles. Pour cela, les bilans azotés et énergétiques de 48 porcs (24 mâles castrés et 24 femelles) d’un poids vif moyende 86 kg et recevant deux formules alimentaires sous forme de farine ou de granulés fabriqués à basse ou à haute température (température en sortie de malaxeur de 55 ou 78 °C) ont été mesurés en chambre respiratoire. La granulation a permis d’améliorer le coefficient d’utilisation digestive de l’azote (+4,0 points) et de l’énergie (+2,6 points) quelle que soit la formule alimentaire. L’augmentation par la granulation de la quantité d’énergie métabolisable ingérée (+165 kJ/kg PV0,60/j) a permis d’augmenter la rétention énergétique (+150 kJ/kg PV0,60/j), en particulier sous forme de lipides, à cause d’une meilleure efficacité d’utilisation de l’énergie et d’une baisse de la production de chaleur liée à l’activité physique. Les mâles castrés ont systématiquement présenté une meilleure réponse à la granulation des régimes par rapport aux femelles. La granulation à basse température a permis d’augmenter de 5% la teneur en énergie nette des régimes. Cette amélioration n’est que de 2,8% pour une température de granulation plus élevée.

As it is mandatory since January 2019 to feed organic pigs and poultry with 100% organic feeds in the EU, abetter knowledge of the nutritional value of organic raw materials is, more than ever, a key for farmers to develop efficient nutrition systems for organic livestock farming. Studies are being conducted in the French CASDAR programme SECALIBIO to compare organic raw materials to conventional ones, to establish the composition and nutritional value of organic feeds, and to evaluate their variability. A database of 6,577 samples of 94 organic raw materials, most of them commonly used in monogastric feeding (soybean meals, maize, faba bean, etc.), was constituted using data from the French Feed Database of the AFZ, from previous research programmes and from feed companies participating in SECALIBIO. In vivo digestibility trials on pigs and poultry were conducted to evaluate the specificities of organic raw materials and provide new data (for forage peas for example). The variability of organic raw materials was generally comparable to that of conventional ones. However, the fat content of organic sunflower (6.2 to 25.2% MS) and soybean (5.37 to 22.6% MS) meals varied a lot due to processing technologies, and it was suggested to delineate categories with consistent crude protein and fibre content. In connection with it, for poultry, the digestibility of protein could vary a lot for sunflower (76.5-83.0%) and soybean (74.4-87.32%) meals. Organic soybean meals was reported to have a lower lysine/crude protein ratio than the conventional one (5.75 vs 6.14%): further investigations will determine the impact of this difference on feed formulation. The first practical result of this study will be the creation of specific tables of composition and nutritional value of organic feeds for pigs and poultry which represents a key for farmers to develop an efficient nutrition system in organic farming.

Livestock may be perceived as less efficient and in competition with crops for the human food supply because they partly consume human-edible feedstuffs to produce milk, eggs or meat. The aim of this study is to estimate the net production of protein for human consumption of ruminant, pig and poultry livestock systems in France. The total protein Conversion Ratio (pCR = kg feed protein consumed/kg protein produced by milk, eggs or meat) does not differentiate human-edible from human non-edible feedstuffs (e.g. grass, byproduct of food and biofuels industries). Thus, we used also the human-edible protein Conversion Ratio (hepCR) that needs to estimate the human-edible protein fraction (hepF) of feedstuffs used in livestock diets. First, we built a table of hepF values for feedstuffs consumed by livestock, applied to the current market and technologies used in the food industries in France (e.g. hepF of wheat grain = 66%, hepF of rapeseed meal = 0%). Then, we estimated the pCR and hepCR values for contrasted feeding systems in ruminants, pigs and poultry. As expected, the pCR values are lower than 1, between 0.05 and 0.25 for ruminant systems, about 0.4 for pigs, 0.3 for laying hens and up to 0.5 for broiler chickens. In contrast, the values of hepCR show that all livestock systems can contribute positively to the human protein supply (hepCR~or>1). Grass-based dairy cow systems can produce up to twice the amount of edible protein they consume (hepCR~2). Pig or poultry systems can respectively produce up to 1.5 (for pig) and 1.3 (for broilers) time more human edible protein that the amount they consume, depending on the proportion of corn, rapeseed/sunflower/soybean meals and other byproducts in the diet. The utilization of grass in ruminant systems and of byproducts in all livestock systems are the key factors to improve the net contribution of livestock production to human food supply, in particular if we consider that advances in food industry technology and modifications of human eating habits can reinforce the feed/food competition in the future.

International audience; The production of pig feeds has a major contribution to climate change, energy use and land occupation impacts of the animal product. Nonetheless, the traditional least-cost (LC) feed formulation methods minimize the cost of the feed mix, without consideration of its environmental impacts. The objective of this study was to estimate the potential mitigation of environmental impacts calculated by Life Cycle Assessment through a multi-objective formulation of pig feeds, in the French context. The linear programming problem built searches the best feed formula under nutritional constraints with a multi-objective function including an economic price index (price of the feed mix relative to LC formulation) and an environmental impacts index (environmental impacts relative to LC formulation). A weighting coefficient between price and environment (α) ranging from 0 to 1 was included. Growing and finishing feeds were formulated with two scenarios of feed ingredients availability (current limited LIM, increased NLIM) and 4 scenarios of feed ingredient prices. When increasing α from 0 to 0.5, the environmental indexes of the growing and finishing feeds dropped down to -10% in LIM and down to -17 to -20% in NLIM scenario, respectively. Concomitantly, the average feed price increased by 1.5% in LIM and 1.7% in NLIM. For α higher than 0.5, the environmental index was almost no further reduced. At α=0.5, all the impacts considered were reduced relatively to LIM-LC, excepted for land occupation in NLIM. The low-impact feeds incorporated higher proportions of pea and wheat middlings and lower proportions of meals (rapeseed and sunflower) than LC formulated feeds. The multi-objective formulation of pig feeds is an efficient methodology to find low-impact feeds according to a given economic scenario. Improving the availability of some feed ingredients (pea, co-products of wheat…) at the territory level would allow (at same feed’s nutritional composition) further reduction of pig feeds impacts relatively to the current French context. Multi-objective formulation can provide a decision support tool to the feed industry to produce low-impact feeds for the pig production chain.

National audience; Les matières premières (MP) riches en fibres sont fréquemment introduites dans les aliments des porcs. Cependant, l’utilisation raisonnable de ces MP nécessite une caractérisation précise de la fraction fibreuse. Les fibres représentent une famille hétérogène de composés aux caractéristiques biochimiques et physicochimiques variées. Plusieurs méthodes permettent de les dosersélectivement mais celle de van Soest et la cellulose brute (CB) sous‐estiment la fraction soluble au contraire de la méthode de Prosky (TDF) alors même que cette fraction est recherchée pour ses effets sur la fonction digestive et la santé. La méthode TDF est, cependant, peu pratiquée en alimentation animale. L’objectif de ce travail est de proposer des équations de prédiction des teneurs en fibres totales solubles et insolubles selon la méthode TDF en fonction de la composition chimique de la MP. A partir de 69 échantillons de MP, les teneurs en MS, MM, MAT, amidon, sucres totaux, MG et les teneurs en fibres selon différentes méthodes (Weende (CB), van Soest, Carré et Prosky (TDF)) ont été déterminées afin de calculer les équations de prédiction des fibres totales, solubles et insolubles par régression linéaire progressive, puis validées avec 25 autres MP. Les meilleures équations de prédiction des fibres totales et insolubles, proposées pour les principales catégories de MP, prennent en compte l’ensemble des constituants autres que les fibres (résidu) ou l’amidon et les protéines. Pour toutes les équations, les ETR sont généralement inférieurs à 3%.Les teneurs en fibres solubles ne peuvent, quant à elles, pas être prédites.

National audience