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The potential of herbal extracts containing bioactive compounds to strengthen immunity could contribute to reducing antimicrobial use in poultry. This study aimed at developing a reliable and robust methodological pipeline to assess the ability of herbal extracts to strengthen chicken innate defenses, especially concerning inflammation and oxidative stress. This methodology was applied to Melissa officinalis L. (MEL) extract, recognized for its biological activities including antioxidant and anti-inflammatory properties. Different methods were used to (1). guarantee the quality of MEL extract and its capacity to stimulate the innate immune system; (2). evaluate the relevance of an ex vivo model to mimic inflammatory and oxidative stress challenges to replace LPS injection in chickens; (3). analyse the effects of feed supplemented with MEL extract on inflammation and oxidative stress induced ex vivo; (4). assess the effects of MEL extract on the redox balance, health, welfare and performance in broilers exposed to suboptimal starting conditions through a large-scale approach. The quality of MEL extract preparations, through phytochemical quantification of rosmarinic acid (RA), revealed varying concentrations of RA in the different MEL extracts. RA concentrations remained stable for at least 9 months and in feed three months after incorporating MEL extract. When incubated with chicken cell lines MEL extract showed potential metabolic activation and ability to stimulate immune functions but induced cytotoxicity at high concentrations. The original ex vivo model of inflammation developed on chicken blood cells enabled inflammation and oxidative stress biomarkers to be expressed and revealed antioxidative and anti-inflammatory properties of blood cells from chickens fed MEL extract. The experimental model of chicken suboptimal starting conditions validated beneficial effects of MEL extract on the redox balance and also evidenced improved performance during the growth phase, a tendency for fewer muscle defects but a higher severity of pododermatitis lesions without affecting other welfare indicators. This study grouped methods and tools that could be combined according to the plant extract, the needs of professionals working in poultry production systems and staff responsible for animal health, welfare and feeding.

International audience

International audience; 1. The aim of the present study was to investigate increasing amount of n-3 fatty acids (FA) in common edible chicken meat cuts by testing different levels of extruded linseeds (LS) and rapeseed oil in growing and finishing diets. Another challenge was to replace a part of soybean meal by faba beans.2. For that purpose, 3168, one-day-old Hubbard JV15 strain chickens were distributed into six groups: R1 = control diet, R2 = 3% then 5% LS, R3 = 4% then 6% LS, R4 = 5% then 7% LS, R5 = 3% then 5% LS and a low amount of soybean meal in the finishing diet and R6 = 3% then 5% LS and no soybean meal in the finishing diet. The growing performance was recorded throughout the trial. At 30 days of age, all chickens were slaughtered in a commercial slaughter plant at an average weight of 1322 g, to mirror the production of low body weight ‘broiler griller’ birds commonly available for export markets. Thirty carcases per group were processed to determine cut yields. The edible parts from each half carcase were removed to determine the chemical composition and fatty acid composition of meat with skin. The sensorial quality of thighs was evaluated for 20 carcases per group, after roasting. The environmental and economic impacts of the feeding programmes were further evaluated.3. This study showed that it was possible to replace a part of the soybean meal in finishing diet by faba beans and to enrich meat with n-3 FA of broiler meat portions without altering growth performance, carcase composition and sensorial quality of meat. The environmental impact was reduced by these dietary interventions, whereby climate change parameters, expressed as kg CO2 eq./T, and phosphorus and fossil energy consumption were lower, but the land occupation was increased. The extra feed cost was +3 to +8% for groups fed R2 to R6 compared to the control group R1.

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.

International audience; The technological, nutritional, and sensorial quality of breasts and thighs with drumsticks of turkey male and female breeders was characterized by comparison with breasts and thighs with drumsticks of growing male and female turkeys from the Grademaker line (hybrid turkeys, n = 20 birds per sex and per physiological stage). The breeder turkeys were slaughtered at 397 and 410 days of age and 10.42 and 32.67 kg of body weight for the females and males, respectively. The standard turkeys were slaughtered at 75 and 103 days of age and 5.89 and 13.48 kg of body weight for the females and males, respectively. The differences observed between males and females on one hand and between standard and breeder turkeys on the other hand were mainly induced by differences in slaughter ages and sexual dimorphism on body weight. The meat of female breeders had characteristics close to those of female and male standard turkeys, whereas the meat of male breeders was clearly distinguishable, particularly by displaying lower tenderness and water holding capacity.

International audience; The aim of this study was to increase the content of n-3 fatty acids (FA) of meat without affecting its sensory and/or technological properties or the growth performance of chickens reared under standard conditions. Male chickens, Ross 308, were distributed into 5 groups corresponding to 5 different diets for the growing and finishing periods: control (T), containing extruded linseeds exhibiting high concentration of fibre (ELHF), extruded linseeds exhibiting low concentration of fibre (ELLF), microalgae, or an association of 75% ELLF and 25% MA (ELLF+MA).The diet containing microalgae induced a decrease in feed consumption without affecting growth rate. Chickens exhibited a lower feed conversion ratio than the other groups for the growing and finishing periods but also the whole rearing period. The use of linseeds in diets had no effect on the growth performance of chickens in comparison to the control group.The dietary enrichment with n-3 FA had few effects on carcass composition or the ultimate pH and colour of breast meat. The microalgae increased the meat susceptibility to oxidation. The lipid content of breast meat was not affected by the diets. The breast meat of chickens fed on diets containing linseeds and/or microalgae had greater n-3 FA content (2.4 to 3.9 times higher than group T). The linseeds and microalgae mainly increased the contents in linolenic acid and long chain n-3 FA, respectively.Dietary enrichment with n-3 FA had no effect on the sensory quality of fillets whereas the thighs of the MA group exhibited the lowest score for the flavour chicken and the greatest score for the flavour abnormal corresponding to a fish flavour.

Overfed hens selected for their rapid growth become fatter and develop reproductive disorders. Herein, we aimed to demonstrate that food restriction leading to a weight reduction and/or a supplementation with fish oil may be effective in preventing reproductive disorders through the regulation of adipokine expression in broiler hens. This study included four groups of food restricted (Rt) orad libitumhens (Ad, feeding at a rate 1.7 times greater than Rt hens) supplemented or unsupplemented with fish oil (1%). The Rt diet significantly increased plasma chemerin (RARRES2) levels during the laying period, delayed sexual maturity by one week and improved egg quality and fertility. These effects were associated with higher progesterone production in response to IGF1 (or LH) in cultured granulosa cells andin vivoegg yolk, as compared with Ad hens. Fish oil supplementation had similar effects to the Rt diet on progesterone (P RARRES2levels were lower in theca cells of Rt hens andNAMPTlevels were increased by the fish oil supplementation. A significant positive correlation betweenRARRES2expression in granulosa cells and the weight of F1 preovulatory follicle was observed, as well as a negative correlation of plasma RARRES2 levels with hatchability. Thus, food restriction but not fish oil supplementation improved fertility, and this was associated with variations in RARRES2 plasma and ovarian expression in hens.

The impact of divergent selection based on the ultimate pH (pHu) of pectoralis major (P. major) muscle on the chemical, biochemical, and histological profiles of the muscle and sensorial quality of meat was investigated in broiler chickens. The protein, lipid, DM, glycogen and lactate content, glycolytic potential, proteolysis, lipid and protein oxidation index, muscle fiber cross-sectional area, capillary density, and collagen surface were determined on the breast P. major muscle of 6-wk-old broilers issued from the high-pHu (pHu+) and low-pHu (pHu-) lines. Sensory attributes were also evaluated on the breast (roasted or grilled) and thigh (roasted) meat of the 2 lines. Protein, lipid, and DM content of P. major muscle were not affected by selection ( > 0.05). However, the P. major muscle of the pHu+ line was characterized by lower residual glycogen (-16%; ≤ 0.001) and lactate (-14%; ≤ 0.001) content and lower glycolytic potential (-14%; ≤ 0.001) compared with the pHu- line. Although the average cross-sectional area of muscle fibers and surface occupied by collagen were similar ( > 0.05) in both lines, fewer capillaries per fiber (-15%; ≤ 0.05) were observed in the pHu+ line. The pHu+ line was also characterized by lower lipid oxidation (thiobarbituric acid reactive substance index: -23%; ≤ 0.05) but protein oxidation and proteolysis index were not different ( > 0.05) between the 2 lines. At the sensory level, selection on breast muscle pHu mainly affected the texture of grilled and roast breast meat, which was judged significantly more tender ( ≤ 0.001) in the pHu+ line, and the acid taste, which was less pronounced in the roasted breast meat of the pHu+ line ( ≤ 0.002). This study highlighted that selection based on pHu does not affect the chemical composition and structure of breast meat. However, by modifying muscle blood supply and glycogen turnover, it affects meat acidity and oxidant status, both of which are likely to contribute to the large differences in texture observed between the 2 lines.

International audience; We assessed whether the ratio of dietary n-6/n-3 polyunsaturated fatty acids (PUFA) during egg formation engenders transgenerational maternal effects in domestic chicks. We analyzed yolk lipid and hormone concentrations, and HPA-axis activity in hens fed a control diet (high n-6/n-3 ratio) or a diet enriched in n-3 PUFAs (low n-6/n-3 ratio) for 6 consecutive weeks. Their chicks were tested for neophobia during the first week of life. We found higher corticosterone metabolites in droppings of hens fed the diet enriched in n-3 and significantly higher concentrations of yolk progesterone, androstenedione, and estradiol in their eggs compared to controls. Chicks of hens fed the n-3 enriched diet showed a lower body mass at hatch than controls and expressed higher neophobia when exposed to a novel object. These results add support to the hypothesis that the nutritional state of female birds produces variation in yolk hormone levels and engender maternal effects.

The welfare of ducks can be affected by unwanted behaviors such as excessive reactivity and feather pecking. Providing long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) during gestation and early life has been shown to improve the brain development and function of human and rodent offspring. The aim of this study was to test whether the pecking behavior of Muscovy ducks during rearing could be reduced by providing LC n-3 PUFA during embryonic and/or post-hatching development of ducklings. Enrichment of eggs, and consequently embryos, with LC n-3 PUFA was achieved by feeding female ducks (n-3F) a diet containing docosahexaenoic (DHA) and linolenic acids (microalgae and linseed oil). A control group of female ducks (CF) was fed a diet containing linoleic acid (soybean oil). Offspring from both groups were fed starter and grower diets enriched with DHA and linolenic acid or only linoleic acid, resulting in four treatment groups with 48 ducklings in each. Several behavioral tests were performed between 1 and 3 weeks of age to analyze the adaptation ability of ducklings. The growth performance, time budget, social interactions, feather growth, and pecking behavior of ducklings were recorded regularly during the rearing period. No significant interaction between maternal and duckling feeding was found. Ducklings from n-3F ducks had a higher body weight at day 0, 28, and 56, a lower feed conversion ratio during the growth period, and lower reactivity to stress than ducklings from CF ducks. Ducklings from n-3F ducks also exhibited a significantly reduced feather pecking frequency at 49 and 56 days of age and for the whole rearing period. Moreover, consumption of diets enriched with n-3 PUFA during the starter and grower post-hatching periods significantly improved the tibia mineralization of ducklings and the fatty acid composition of thigh muscles at 84 days of age by increasing the n-3 FA content.

Decades of genetic selection have generated 2 different, highly specialized types of chickens in which 1 type, known as the layer-type chicken, expresses high laying performance while the other type, known as the broiler-type chicken, is dedicated to the production of fast-growing birds. Selected lines for the latter type often express disorders in their reproductive performance including early sexual maturation and accelerated, non-reversible seasonal decline of their semen production and mating behavior. The aim of the present study was to characterize some metabolic markers of the Sertoli cell populations. Sertoli cells are somatic cells known to support, coordinate, nourish, and protect the germ cell populations from onset to the end of their meiotic process. Comparisons of gonadal development between males of the 2 genetic types taken at their pre-pubertal period indicated that the testes of layer-type chickens are significantly less developed than in broiler-type males taken at the same age. In addition, cultures of purified Sertoli cells from the 2 types revealed in vitro a higher proliferative capacity when issued from layer compared to broiler-type chickens. This was associated with a higher expression of the genes involved in the beta-oxidation of fatty acids (CPT1; PPARβ) as well as a 4-fold increase in the Lactate Dehydrogenase-A expression and activity. In contrast, Sertoli cells from broiler-type chickens presented an elevated activity of citrate synthase and mitochondria, suggesting a better efficacy of aerobic metabolism in Sertoli cells from broiler compared to layer-type chickens. Moreover, the testis from broiler-type chickens seems to be more sensitive to oxidative stress due to the lower global antioxidant capacity compared to layer-type chickens.In conclusion, these results suggest that the metabolic activity of testicular tissues is different in the layer and broiler breeder chickens. The aerobic metabolism more prevalent in broiler-type chickens could be a factor to reduce the male fertility such as germ cell quality.

International audience; The aim of this study was to analyse the effects of species (Muscovy and Pekin ducks) and age at the beginning of the overfeeding period on fatty liver production, carcass composition and lipid and moisture content of the liver and breast muscle. We reared four groups of 40 ducks per species for the study, starting at 2-week intervals in order to have four different ages together at the beginning of the overfeeding period (10, 12, 14 and 16 weeks). At the end of the overfeeding period, all ducks were slaughtered. Our results confirmed the high levels of difference in carcass composition and lipid content in the plasma, liver and breast muscle between Muscovy and Pekin ducks at all ages. Pekin ducks were not able to develop a high degree of hepatic steatosis, but had increased lipid storage in peripheral adipose and muscle tissues than Muscovy ducks. However, the fatty liver weight of Pekin ducks increased with age, with lipid deposition in the liver and peripheral tissues. The ability of Muscovy ducks to produce fatty livers remained unchanged with age in line, with lipid deposition in the liver and peripheral tissues. The sites of lipid deposition thus depend on species and not on the physiological maturity of ducks.

Cette revue a pour objectif de faire un point sur les avancées récentes obtenues dans le domaine de la prédiction de la qualité des viandes. Elle aborde différentes démarches menées au sein des principales filières de production pour développer des équations puis des outils prédictifs basés sur différents types de marqueurs biologiques (génomiques ou phénotypiques) ou physiques (spectroscopiques). Au travers des différents exemples présentés, il apparaît que l’identification de marqueurs biologiques se confronte au déterminisme complexe des paramètres de qualité qui rend encore difficile la mise au point de tests moléculaires génériques utilisables sur le terrain. Toutefois, les avancées ont été notables ces dernières années bénéficiant des récents développements technologiques en génomique, protéomique et métabolomique. Les premières équations de prédiction de la qualité sensorielle et du potentiel technologique des viandes laissent entrevoir des possibilités d’applications dans les années à venir. Concernant la spectroscopie, les principaux résultats ont été obtenus dans le domaine de la Spectroscopie Proche Infrarouge (SPIR) avec des développements aboutis pour prédire la composition et la valeur nutritionnelle des viandes. La prédiction du potentiel technologique des viandes à l’aide de cette méthode et surtout de la qualité sensorielle est en revanche plus difficile. Enfin, l’exemple du modèle phénotypique MSA (« Meat Standards Australia ») de prévision de la qualité sensorielle de la viande bovine basée sur une combinaison de données d’amont et d’aval et dont la plus-value pour la filière a été démontrée en Australie, présente une généricité qui a déjà été éprouvée dans plusieurs pays., This review was aimed at providing an overview of recent advancements obtained in the field of meat quality prediction. The different methods used in the production sectors for the development of equations and the tools used based on different types of biological markers (genomic or phenotypic) or physical (spectroscopy) are discussed. Through the different examples that are presented, it appears that the identification of biological markers is confronted with the complex determinism of quality parameters. This makes the development of generic molecular tests to be used on the field even more difficult. However, in recent years, progress has been made, benefitting from genomics, proteomics and metabolomics technological developments. The first equations that predict the sensorial quality and the technological potential of meat hint to possible applications in the near future. Concerning spectroscopy, the main results were obtained using Near Infrared Spectroscopy (NIR) with developments obtained for the prediction of the composition and nutritional value of meats. The prediction of the technological potential of meats using this method and mainly the sensorial quality is, however, more difficult. Finally, the example of the MSA (« Meat Standards Australia ») phenotypic model which predicts the sensorial quality of bovine meat based on a combination of upstream and downstream data and whose added-value for the sector has been identified in Australia, presents a genericness that has already been proven in several countries.

Background White striping (WS) is an emerging quality defect with adverse consequences for the sensorial, technological, and nutritional qualities of breast meat in broiler chickens. The genetic determinism of this defect is little understood and thus the aim of the study presented here was to estimate the genetic parameters of WS in relation to other traits of economic importance such as body weight, carcass composition, and technological meat quality in an experimental population consisting of two divergent lines selected for high (pHu + line) or low (pHu- line) ultimate pH (pHu) of the pectoralis major (p. major) muscle. Results The incidence of WS in the whole population was 50.7 %, with 36.7 % of broilers being moderately and 14 % being severely affected. A higher incidence of moderate (p

Because of the increasing demand for raw cuts and processed products, there is a trend to producing very heavy broilers. Breeds that are used for such kinds of production have been intensively selected for growth rate and breast meat yield, and birds are reared for a longer period than standard broilers. This study was to evaluate the effects of increasing slaughter age on technical and economic factors, including production efficiency and environmental costs, bird welfare, and breast meat quality in a modern heavy broiler line. Five groups of 300 male Ross 708 chickens were reared until slaughter ages of 35, 42, 49, 56, or 63 d. Increasing age at slaughter from 35 to 63 d resulted in a 7.4-fold increase (P < 0.01) in mortality rate (5.21 vs. 0.70%). It also increased (P < 0.001) the slaughter weight and ADFI of birds 2.5- and 1.4-fold, respectively, without affecting their G:F. Under our experimental conditions, economic profit evaluated through the net gain reached a maximum at 42 d. The moisture and ammonium content of litter increased (P < 0.05 and P < 0.01, respectively) rapidly during rearing concomitantly with increased (P < 0.05) occurrence and severity of contact dermatitis and decreased (P < 0.05) walking ability and activity of birds. Thermal comfort also decreased (P < 0.05) greatly as early as 42 d of age. Changes in carcass quality occurred mainly between 35 and 56 d of age, with a progressive increase (P < 0.001) in breast and leg yield, whereas body fatness was barely affected by age. Major changes in breast meat traits were observed between 35 and 49 d of age, with an increase in muscle pH at 15 min (P < 0.01) and 24 h (P < 0.001) postmortem and reduced (P < 0.001) lightness and drip loss. The protein and lipid content of raw breast meat also increased (P < 0.05 and P < 0.01, respectively) with age. Taking into account the main aspects of sustainability, we could recommend slaughtering chickens of heavy line at 42 d of age.

Background Reproductive hens are subjected to a restricted diet to limit the decline in fertility associated with change in body mass. However, endocrine and tissue responses to diet restriction need to be documented. Objective We evaluated the effect of different levels of feed restriction, with or without fish oil supplementation, on metabolic parameters and adipokine levels in plasma and metabolic tissues of reproductive hens. Methods We designed an in vivo protocol involving 4 groups of hens; RNS: restricted (Rt) unsupplemented, ANS: ad libitum (Ad, receiving an amount of feed 1.7 times greater than animals on the restricted diet) unsupplemented, RS: Rt supplemented, and AS: Ad supplemented. The fish oil supplement was used at 1% of the total diet composition. Results Hens fed with the Rt diet had a significantly (P < 0.0001) lower growth than Ad hens, while the fish oil supplementation had no effect on these parameters. Furthermore, the bioelectrical impedance analysis (BIA) and the fat ultrasonographic examinations produced similar results to the other methods that required animals to be killed (carcass analysis and weight of adipose tissue). In addition, the Rt diet significantly (P < 0.05) decreased plasma levels of triglycerides, phospholipids, glucose and ADIPOQ, and fish oil supplementation decreased plasma levels of RARRES2. We also showed a positive correlation between insulin values and ADIPOQ or NAMPT or RARRES2 values, and a negative correlation of fat percentage to RARRES2 values. Moreover, the effects of the Rt diet and fish oil supplementation on the mRNA expression depended on the factors tested and the hen age. Conclusions Rt diet and fish oil supplementation are able to modulate metabolic parameters and the expression of adipokines and their receptors in metabolic tissue.

Chantier qualité GA; International audience; The aim of this study was to determine the specific characteristics of carcass and meat from an old French chicken breed, the 'Geline de Touraine' (GT), characterised by a very slow-growing rate and usually slaughtered at 120 days of age. For this purpose, we compared the GT with an experimental crossbreed (EC) exhibiting the same growth rate, and with a 'Label rouge' (LR) genotype usually slaughtered at 84 days of age. A total of 250 males and 250 females per genotype were reared by separating sexes and genotypes. The growth performances were recorded. At 84 days of age, 80 birds per sex and per genotype were slaughtered. The frequency of clawing and pecking injuries on the carcass was noted. We also measured the skin colour and the thickness of wing membrane. The relative percentages of carcass, breast, thigh + drumstick, abdominal fat, testis or ovary to body weight were determined. On breast and thigh muscles the ultimate pH (pHu) and colour were measured. The juice loss after 3 days' storage at + 4 degrees C and after cooking at 85 degrees C, and the shear force value of Warner-Bratzler were only measured on breast muscles. At 120 days of age, we repeated the same measurements but only on EC and GT genotypes in order to compare birds at the same age or at the respective slaughter age for each production. Whatever the slaughter age, the body weight of males was always higher than that of the females but the carcass yield was similar for both sexes. The females had higher breast yield and carcass fatness but lower thigh + drumstick yield than the males. The yellowness of skin and meat was higher for the females than for the males while the contrary was observed for the redness of the meat. The breast meat of the females also had higher cooking loss than that of the males. GT and EC birds exhibited a higher occurrence of carcass defects and a higher pHu in meat than LR birds. The GT chickens were characterised by a lower breast yield, a higher fattiness and an earlier sexual maturity than the other genotypes, which could confer typical sensorial attributes to their meat. Finally, the EC chickens exhibited a skin and a meat more coloured than the other genotypes, particularly for yellowness, a character which could be under genetic control.

The present study was aimed at evaluating the molecular mechanisms associated with the differences in muscle glycogen content and breast meat quality between 2 experimental lines of chicken divergently selected on abdominal fatness. The glycogen at death (estimated through the glycolytic potential) of the pectoralis major muscle and the quality of the resulting meat were estimated in the 2 lines. The fat chickens exhibited greater glycolytic potential, and in turn lower ultimate pH than the lean chickens. Consequently, the breast meat of fat birds was paler and less colored (i.e., less red and yellow), and exhibited greater drip loss compared with that of lean birds. In relation to these variations, transcription and activation levels of adenosine monophosphate-activated protein kinase (AMPK) were investigated. The main difference observed between lines was a 3-fold greater level of AMPK activation, evaluated through phosphorylation of AMPKalpha-(Thr(172)), in the muscle of lean birds. At the transcriptional level, data indicated concomitant down- and upregulation for the gamma1 and gamma2 AMPK subunit isoforms, respectively, in the muscle of lean chickens. Transcriptional levels of enzymes directly involved in glycogen turnover were also investigated. Data showed greater gene expression for glycogen synthase, glycogen phosphorylase, and the gamma subunit of phosphorylase kinase in lean birds. Together, these data indicate that selection on body fatness in chicken alters the muscle glycogen turnover and content and consequently the quality traits of the resulting meat. Alterations of AMPK activity could play a key role in these changes.

International audience; The aim of this study was to increase the n-3 fatty acid (n-3 FA) content of eggs without affecting their sensorial and/or technological properties or the laying performance of hens. Laying hens from line 477 were divided into 5 groups corresponding to 5 different diets over the laying period: control diet (C) and diets containing extruded linseed with a high level of fibre (ELHF), extruded linseed with a low level of fibre (ELLF), microalgae, or a combination of 75% ELLF and 25% MA (ELLF+MA). Dietary enrichment with n-3 FA had no effect on the laying performance, hen body weight or egg white viscosity. The egg yolks produced by hens fed the diet containing microalgae were redder than egg yolks from the other groups, suggesting the presence of red pigments in the microalgae preparation. However, the colour difference was low and not perceptible to the human eye. Moreover, colour measurement of egg yolks by sensorial analysis panellists using the Roche colour fan did not reveal a diet effect on this parameter. Egg yolk lipid content was not affected by diet. The egg yolk of hens fed on diets containing linseed and/or microalgae had greater n-3 FA content (×2.5 to 2.9 compared to group C). Linseed mainly increased the linolenic acid content (×3.0 to 3.4 compared to group C) and the microalgae increased the LC n-3 FA content (×4.1 compared to group C). Dietary enrichment with n-3 FA had no effect on the sensorial quality of shell cooked eggs except for the "unusual flavour" criterion for which the score was higher for the MA group compared to the other groups and corresponded to a fishy flavour.

The increasing use of unconventional feedstuffs in chicken's diets results in the substitution of starch by lipids as the main dietary energy source. To evaluate the responses of genetically fat or lean chickens to these diets, males of two experimental lines divergently selected for abdominal fat content were fed isocaloric, isonitrogenous diets with either high lipid (80 g/kg), high fiber (64 g/kg) contents (HL), or low lipid (20 g/kg), low fiber (21 g/kg) contents (LL) from 22 to 63 days of age. The diet had no effect on growth performance and did not affect body composition evaluated at 63 days of age. Glycolytic and oxidative energy metabolisms in the liver and glycogen storage in liver and Sartorius muscle at 63 days of age were greater in chicken fed LL diet compared with chicken fed HL diet. In Pectoralis major (PM) muscle, energy metabolisms and glycogen content were not different between diets. There were no dietary-associated differences in lipid contents of the liver, muscles and abdominal fat. However, the percentages of saturated (SFA) and monounsaturated fatty acids (MUFA) in tissue lipids were generally higher, whereas percentages of polyunsaturated fatty acids (PUFA) were lower for diet LL than for diet HL. The fat line had a greater feed intake and average daily gain, but gain to feed ratio was lower in that line compared with the lean line. Fat chickens were heavier than lean chickens at 63 days of age. Their carcass fatness was higher and their muscle yield was lower than those of lean chickens. The oxidative enzyme activities in the liver were lower in the fat line than in the lean line, but line did not affect energy metabolism in muscles. The hepatic glycogen content was not different between lines, whereas glycogen content and glycolytic potential were higher in the PM muscle of fat chickens compared with lean chickens. Lipid contents in the liver, muscles and abdominal fat did not differ between lines, but fat chickens stored less MUFA and more PUFA in abdominal fat and muscles than lean chickens. Except for the fatty acid composition of liver and abdominal fat, no interaction between line and diet was observed. In conclusion, the amount of lipids stored in muscles and fatty tissues by lean or fat chickens did not depend on the dietary energy source.

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n-3 PUFA are crucial for health and development. Their effects as regulators of lipid and glucose metabolism are well documented. They also appear to affect protein metabolism, especially by acting on insulin sensitivity. The aim of the present study was to investigate the role ofn-3 PUFA, i.e. the precursor α-linolenic acid (ALA) 18 : 3n-3 or long-chain PUFA (LC-PUFA), in chickens, by focusing on their potential function as co-regulators of the insulin anabolic signalling cascade. Ross male broilers were divided into six dietary treatment groups. Diets were isoproteic (22 % crude protein) and isoenergetic (12·54 MJ metabolisable energy/kg) and contained similar lipid levels (6 %) provided by different proportions of various lipid sources: oleic sunflower oil rich in 18 : 1n-9 as control; fish oil rich in LC-PUFA; rapeseed and linseed oils providing ALA. The provision of diets enriched withn-3 PUFA, i.e. rich in LC-PUFA or in the precursor ALA, for 3 weeks improved the growth performance of chickens, whereas that of only the ALA diet enhanced the development of the pectoralis major muscle. At 23 d of age, we studied the insulin sensitivity of the pectoralis major muscle and liver of chickens after an intravenous injection of insulin or saline. The present results indicate that the activation patterns ofn-3 PUFA are different in the liver and muscles. An ALA-enriched diet may improve insulin sensitivity in muscles, with greater activation of the insulin-induced 70 kDa ribosomal protein S6 kinase/ribosomal protein S6 pathway involved in the translation of mRNA into proteins, thereby potentially increasing muscle protein synthesis and growth. Our findings provide a basis on which to optimise dietary fatty acid provision in growing animals.

An indirect electrochemical method, which is very efficient for the degradation of organic pollutants in water, is described. The method, named electro-Fenton, is based on electrocatalytical generation of Fenton's reagent to produce hydroxyl radicals, which are very active toward organic compounds. An industrial pollutant, p-nitrophenol (PNP), was chosen for this study and was eventually mineralized. The major intermediary degradation products such as hydroquinone, benzoquinone, 4-nitrocatechol, 1,2,4-trihydroxybenzene and 3,4,5-trihydroxy- nitrobenzene were unequivocally identified by HPLC and GC-MS methods. The rate constants of the hydroxylation reactions were determined. The mineralization of the initial pollutant and the intermediates formed during electro-Fenton treatment was followed by total organic carbon (TOC) analyses. Dependence of mineralization on the amount of electrical energy consumed is shown by the relative decrease of TOC values. A mineralization reaction mechanism is proposed.

Introduction et but de l’etude L’objectif de cette etude etait d’augmenter la teneur en acides gras n-3 des œufs sans alterer leurs proprietes sensorielles et/ou technologiques ni les performances de ponte des poules et tester de nouvelle sources alimentaires d’AG n-3 (graines de lin a faibles teneurs en fibres et microalgues). Materiel et methodes Au total, 200 poules pondeuses de souche 477 reparties en 5 lots de 40 poules correspondant a 5 types d’aliment pour le debut de la periode de ponte ont ete elevees : temoin (T), contenant des graines de lin extrudees riches en fibres (GLE), des graines de lin extrudees a faible teneur en fibres (GLDP), des microalgues (MA) ou une association de 75 % GLDP et 25 % MA (GLDP + MA). Tous les aliments etaient supplementes en vitamine E (100 ppm). Les 5 aliments etaient isoenergetiques et isoproteiques. Les aliments experimentaux enrichis en AG n-3 etaient egalement isoquantitatifs en AG n-3 et lipides. La consommation alimentaire a ete enregistree de 21 a 33 semaines en pesant l’aliment distribue et les refus d’aliment par cage et par periode de 4 semaines. Les performances de ponte de 21 a 33 semaines ont ete suivies en notant pour chaque poule et chaque jour, le nombre d’œufs pondus, le poids des œufs (faire une moyenne par poule et par semaine sur 4 jours de collecte, du mardi au vendredi) et les caracteristiques de ces œufs (œuf double qu’il faudra peser individuellement, œuf sale, œuf fele…). De 26 a 31 semaines, les œufs ont ete collectes chaque semaine afin de constituer 3 pools de 5 œufs par lot pour determiner la teneur en lipides totaux et la composition en acides gras sur les jaunes d’œuf de chaque pool. Les unites Haugh qui permettent d’estimer la viscosite du blanc et la couleur du jaune d’œuf ont aussi ete mesurees. A 27 et 32 semaines au moins 80 œufs par lot ont ete collectes pour l’analyse sensorielle sur œufs cuits a la coque. Resultats et Analyse statistique L’enrichissement en AG n-3 du regime alimentaire n’a pas eu d’effet sur les performances de ponte et le poids des animaux. Les unites Haugh n’ont pas ete affectees par le traitement alimentaire. Les poules nourries avec l’aliment contenant des microalgues ont produit des œufs dont le jaune etait plus rouge et plus fonce suggerant la presence de pigments rouges dans la preparation de microalgues. Neanmoins, la difference de coloration avec les autres lots n’est en principe pas perceptible par l’œil humain. La mesure avec l’echelle Roche de la coloration du jaune d’œuf par les jures d’analyse sensorielle n’a effectivement pas mis en evidence d’effet de la source alimentaire en lipides sur ce parametre. La teneur en lipides des œufs n’est pas affectee par le traitement alimentaire. Les œufs des poules alimentees avec les regimes contenant des graines de lin et/ou des microalgues sont bien enrichis en AG n-3 (teneur X 2,5 a 2,9 par rapport au temoin). Comme attendu, avec les graines de lin, c’est essentiellement la teneur en acide linolenique (C18 :3 n-3) qui est accrue (X 3,0 a 3,4 par rapport au temoin). Avec les microalgues, c’est essentiellement la teneur en AG n-3 a longues chaines (EPA, DPA, DHA) qui est augmentee (X 4,1 par rapport au temoin). Le lot GLDP + MA presente des teneurs intermediaires pour ces categories d’AG. La source alimentaire en lipides n’a pas eu d’effet sur l’analyse sensorielle des œufs cuits a la coque a l’exception du critere « flaveur anormale » dont la note est plus elevee pour le lot MA avec un qualificatif de flaveur de poisson. Conclusion L’augmentation notable de la proportion d’acides gras n-3 dans les regimes experimentaux n’a pas eu d’effet sur les performances de ponte et le poids vif des poules. La qualite nutritionnelle des œufs a ete amelioree (teneur plus elevee en AG n-3) tandis que la qualite technologique n’etait pas affectee. Les deux sources d’acide linolenique (GLDP et GLE) ont accru la teneur en AG n-3 des œufs dans les memes proportions. Afin d’eviter l’effet deletere des microalgues sur les caracteristiques sensorielles des œufs, il est preferable de limiter leur taux d’incorporation dans l’aliment et de les associer avec des graines de lin pour conserver une teneur elevee en AG n-3 LC.

Introduction et but de l’etude L’objectif de cette etude etait d’augmenter la teneur en acides gras n-3 de la viande sans alterer ses proprietes sensorielles et/ou technologiques ni les performances de croissance de poulets eleves en conditions standards et tester de nouvelle sources alimentaires d’AG n-3 (graines de lin a faibles teneurs en fibres et microalgues). Materiel et methodes Au total, 450 poulets mâles de souche Ross 308 repartis en 5 lots correspondant a 5 types d’aliment pour les periodes de croissance et de finition ont ete eleves : temoin (T), contenant des graines de lin extrudees riches en fibres (GLE), des graines de lin extrudees a faible teneur en fibres (GLDP), des microalgues (MA) ou une association de 75 % GLDP et 25 % MA (GLDP+MA). Les 5 aliments croissance puis les 5 aliments finition etaient isoenergetiques et isoproteiques. Les aliments experimentaux enrichis en AG n-3 etaient egalement isoquantitatifs en AG n-3 et lipides. Les animaux ont tous ete peses a J11, J21 et J42. La consommation alimentaire a ete enregistree sur les memes periodes (pesee de l’aliment distribue et des refus par parquet). A J42, 42 poulets par lot ont ete abattus. Les carcasses ont ete stockees a +4 °C pendant 24 h avant d’etre decoupees pour determiner la composition corporelle. La couleur et le pH ultime (pHu) ont ete mesures sur les filets. La sensibilite a l’oxydation de la viande a ete estimee en mesurant l’indice TBARS sur les filets stockes a +4 °C pendant 7 jours puis cuits (n = 15). La teneur en lipides et la composition en acides gras ont egalement ete determinees (n = 15). L’analyse sensorielle sur les cuisses et les filets a ete realisee sur des carcasses roties (n = 20). Resultats et Analyse statistique L’apport de microalgues dans le regime alimentaire a eu pour effet de diminuer la consommation alimentaire sans affecter la croissance des animaux qui presentaient un meilleur indice de consommation que ceux des autres lots pour les periodes de croissance (J11-J21) et finition (J21-J42) et pour la periode globale d’elevage. L’apport de lin dans le regime alimentaire n’a pas modifie les performances de croissance des animaux par comparaison avec le lot temoin. L’enrichissement en AG n-3 du regime alimentaire a peu affecte la composition corporelle des animaux, le pHu et la couleur des filets. L’apport de microalgues dans le regime alimentaire a egalement accru la sensibilite de la viande a l’oxydation. La teneur en lipides des filets n’est pas affectee par le traitement alimentaire. Les filets des poulets alimentes avec les regimes contenant des graines de lin et/ou des microalgues sont bien enrichis en AG n-3 (X 2,4 a 3,9 par rapport au temoin). Comme attendu, avec les graines de lin, c’est surtout la teneur en acide linolenique qui est accrue (X 2,4 a 2,8 par rapport au temoin). Avec les microalgues, c’est essentiellement la teneur en AG n-3 a longues chaines qui est augmentee (X 9,3 par rapport au temoin). Le lot GLDP+MA presente des teneurs intermediaires pour ces categories d’AG. L’enrichissement en AG n-3 du regime alimentaire n’a pas eu d’impact sur la qualite sensorielle des filets. Par contre, les cuisses du lot MA ont la plus faible note pour la « flaveur poulet » et la note la plus elevee pour la « flaveur anormale » correspondant en fait a une flaveur de poisson. Conclusion L’augmentation notable de la proportion d’acides gras n-3 dans les regimes experimentaux a eu peu d’effet sur les performances de croissance et le rendement en viande des poulets standards. La qualite nutritionnelle des filets a ete amelioree tandis que la qualite technologique de la viande etait peu affectee. Les deux sources d’acide linolenique (GLDP et GLE) ont accru la teneur en AG n-3 des filets dans les memes proportions. Afin d’eviter l’effet deletere des microalgues sur la sensibilite a l’oxydation et les caracteristiques sensorielles de la viande, il est preferable de limiter leur taux d’incorporation dans l’aliment et de les associer avec des graines de lin pour conserver une teneur elevee en AG n-3 LC dans la viande.

International audience; The enrichment of raw poultry meat with n3 fatty acids (n3 FA) has been investigated in detail, particularly in high growth rate genotype standard broiler chickens, whereas low growth rate genotype Label Rouge chickens have received less attention. With the increased development of processed poultry products, it is necessary to ensure that the nutritional and sensory quality of meat enriched with n3 FA is not affected by processing. 2. Two experiments were undertaken for this purpose. In the first experiment, 696 male Ross 708 chickens were reared under standard conditions, and in the second, 750 male JA 657 chickens were reared under Label Rouge conditions. All birds received the same starting and growing diets containing palm and soya oils in each experiment. Birds were distributed into three groups from 21 or 57 d of age for standard and Label Rouge chickens, respectively, and given a control, linseed oil or extruded linseed diet. Diets were also supplemented with vitamin E (100200mg/kg). Birds were slaughtered at 56 or 84 d of age for standard and Label Rouge chickens, respectively. A total amount of 60kg of breast meat from each group was processed into white cured-cooked meat. 3. The dietary treatment had no effect on the growth performance of chickens or meat yield. The use of extruded linseed or linseed oil only decreased the carcass fatness of the standard chickens but had no effect on the carcass fatness of Label Rouge chickens. The nutritional quality of raw and cured-cooked meat was improved (increased concentration of n3 FA), whereas the technological quality of the meat (pH, juice loss after cold storage, susceptibility to oxidation, colour, processing yield and shear force value) and sensory quality of the processed products were not or slightly affected. 4. Linked to lower breast yield, to lower lipid content in breast meat and to higher slaughter age, Label Rouge chickens seemed to be less efficient for n3 FA deposition in breast muscles than standard chickens.

Broiler chickens have limited capacities to sustain high temperatures. However, thermal manipulation (TM) during embryogenesis has been shown to lower their body temperature at hatch and to improve thermotolerance until market age (Piestun et al., 2008). This thermotolerance acquisition could partly be due to changes in sensible heat loss, but also in metabolic rate, especially in energy and protein metabolisms of birds. The aim of this study was to evaluate the long-lasting effects of TM during embryogenesis, when coupled or not with a heat challenge at slaughter age (d 34), on plasma metabolites and hormones, cell signaling and the expression of genes involved in muscle metabolism.

N-3 polyunsaturated fatty acids (PUFA) are crucial for normal development and organ functioning in vertebrates. Their pleiotropic effects are well documented as regulators of lipid and glucose metabolism, but less known with regard to protein metabolism. Recent studies indicate that the consumption of long-chain PUFA (LC-PUFA) promotes muscle protein anabolism both in farm animals (Gingras et al., 2007) or humans (Smith et al. 2011a,b). These studies suggest that n-3 PUFA may act by increasing insulin sensitivity rather than by regulating gene transcription. It should be noted that these studies were performed using n-3 LC-PUFA abundant in fish oils (20 and 22 carbons) and effects of the vegetal precursor α-linolenic acid (ALA, C18:3 n-3) have never been explored. Moreover, the consequences on other tissues than muscle are unknown. Our aim was to investigate the role of n-3 PUFA (ALA or LC-PUFA) on liver protein metabolism in chickens, by focusing on their potential function as co-regulators of the insulin signaling cascade.

Background Slow-growing lines are widely used in France for the production of high quality free-range chickens. While such production is mainly dedicated to the whole carcass market, new prospects are opening up for the development of cuts and processed products. Whether the body composition and meat quality of slow-growing birds can be improved by selection has thus become an important issue. The genetic parameters of growth, body composition and breast meat quality traits were evaluated in relation to behaviour at slaughter in a large pedigree population including 1022 male and female slow-growing birds. Results The heritability coefficients (h2) of body weight and body composition traits varied from 0.3 to 0.5. Abdominal fat percentage was genetically positively correlated with body weight but negatively correlated with breast muscle yield. The characteristics of the breast meat (i.e., post-mortem fall in pH, colour, drip loss, shear-force and lipid content) were all heritable, with h2 estimates ranging from 0.18 to 0.48. The rate and extent of the fall in pH were under different genetic control. Strong negative genetic correlations were found between the ultimate pH and the lightness, yellowness and drip loss of the meat. Wing flapping on the shackle line was significantly heritable and exhibited marked genetic correlations with the pH at 15 min post-slaughter and the redness of the meat. The genetic relationships between meat quality traits, body weight and body composition appeared slightly different between males and females. Conclusion This study suggested that there are a number of important criteria for selection on carcass and breast meat quality in slow-growing birds. Selection for reduced abdominal fatness and increased breast muscle yield should be effective as both traits were found to be highly heritable and favourably correlated. Substantial improvement in meat quality could be achieved by selection on ultimate pH which was highly heritable and strongly correlated with the colour and water-holding capacity of the meat. Moreover, this study revealed for the first time that the behaviour at slaughter is partly genetically determined in the chicken.

Le programme de recherches GENECAN repose sur 1) la production de familles informatives par un croisement entre 2 souches expérimentales d'origines et d'aptitudes différentes (INRA-UEPFG), 2) la mesure des phénotypes sur les canes back-cross (BC) et leurs descendants mulards (INRA-URA, INPENSAT, UPPA-CNRS, INRA-UEPFG) et mulardes (INRA-IASP), 3) le génotypage des animaux (plateforme de la Génopole toulousaine, INRA-LGC) à l’aide d’un panel de 116 marqueurs informatifs et 4) l'analyse statistique pour détecter les QTL (INRA-SAGA). A partir des performances des males mulards, 65 QTL ont pu être détectés : 13 pour des caractères de croissance, 18 pour des caractères métaboliques et pondéraux durant le gavage, 8 pour des caractères d’aptitude au gavage, 12 pour des caractères de qualité du magret et 14 pour des caractères de qualité du foie gras.

Chantier qualité GA; The susceptibility to development of hepatic steatosis is known to differ between Muscovy and Pekin ducks. Although some experiments were conducted to decipher these differences, few data have been produced to analyse the role of specific genes in this process. For this purpose, expression levels of genes involved in lipid (ATP citrate lyase, malic enzyme 1, fatty acid synthase, stearoyl-CoA desaturase 1, diacylglycerol O-acyl transferase 2, microsomal triglyceride transfer protein, apolipoprotein A1, apolipoprotein B, sterol regulatory element binding factor 1, hepatocyte nuclear factor 4, choline/ethanolamine phosphotransferase 1, carnitine palmitoyl transferase 1A, peroxisome proliferator-activated receptor alpha and sterol O-acyltransferase) and carbohydrate (activating transcription factor 4 or cAMP-response element binding protein, mitochondrial malate dehydrogenase 2 and carbohydrate responsive element binding protein) metabolism and in other functions were analysed in the liver of Pekin and Muscovy ducks fed ad libitum or overfed. A specific positive effect of feeding was observed on the expression of genes involved mainly in fatty acids and TG synthesis and glycolysis, and negative effect on genes involved in beta-oxidation. Interestingly, a strong species effect was also observed on stearoyl-CoA desaturase 1 and to a lesser extent on diacylglycerol O-acyl transferase 2 expression, leading to large differences in expression levels between Pekin and Muscovy overfed ducks, which could explain the difference in lipid metabolism and steatosis ability observed between the two duck species. These results should shed light on gene expression that might underlie susceptibility to hepatic steatosis in humans.

International audience; 1. The aim of this study was to examine the effect of sex and genotype on carcase composition and nutritional and sensory characteristics of chicken meat. The oGeline de Touraineo (GT) characterised by high carcase fatness was compared with an experimental crossbreed (EC) and oLabel rougeo (LR) genotype. 2. Females compared with males, and GT chickens compared with LR and EC chickens were characterised by increased carcase fatness and an increased lipid level in thigh meat. 3. In both breast and thigh meat, the percentage of monounsaturated fatty acids was increased and the percentage of polyunsaturated fatty acids was decreased. However, these effects did not affect sensory characteristics of meat particularly those of roasted breast fillets containing very low lipid level by comparison with thigh meat. 4. Finally, in our study, high carcase fatness was related to high intermuscular fatness affecting the nutritional characteristics of meat but not its sensory attributes.

Chantier qualité GA; International audience; To explore the mechanisms leading to excessive adiposity in chicken, we investigated the regulation of fatty acid oxidation depending on genotype-related body fatness and diet composition. mRNA expression and/or activity of proteins involved in mitochondrial energy metabolism were measured in liver and gastrocnemius muscle of genetically lean or fat chickens reared on a low-fat/high-protein diet or an isoenergetic high-fat/low-protein diet (HF/LP). Muscle expressions of the muscle isoform of carnitine-paimitoyltransferase 1 (M-CPT1) and PPAR beta/delta were higher in fat than in lean chickens. This was also observed in liver, although only with the HF/LP diet for M-CPTI. This could stimulate mitochondrial fatty add oxidation in fat chickens. Up-regulations of liver and muscle CPT-1 hepatic isoform, and muscle cytochrome-c-oxidase mRNA expressions, and of beta-hydroxyacyl-CoA-dehydrogenase activities suggest higher fatty acid utilization with the HF/LP diet. PPAR beta/delta and PGC-1 alpha could control fatty acid oxidation in muscle and liver, respectively. Regulation of avian uncoupling protein (avUCP) mRNA was tissue-dependent. Predominantly expressed in muscle, it was stimulated in fat and in HF/LP-fed chickens, where it could be associated to the special need in muscle anti-oxidant pathways of fatter animals. In liver it was lower in fat than in lean chickens, and its potential function remains to be clarified.

International audience; In mammals, carnitine palmitoyltransferase 1 (CPT1) is a rate limiting enzyme of fatty acid oxidation. Two isoforms are present. We characterized a full-length cDNA sequence encoding chicken liver L-CPT1 isoform and a partial cDNA sequence encoding chicken muscle MCPT1 isoform. CPT1 messengers showed the expected tissue specificity. M-CPT1 messenger and CPT1 activity were higher in oxidative than in glycolytic muscle. Expression of both isoforms was assessed in various tissues of genetically fat or lean chickens. Fasting considerably increased L-CPT1 mRNA expression and β-hydroxyacyl CoA dehydrogenase (HAD) activity in the liver of fat or lean chickens. Unexpectedly, fasting did not increase M-CPT1 mRNA levels nor HAD activity in muscles of either chicken genotype. It however increased succinyl-CoA:3-ketoacid CoA transferase (SCOT) mRNA expression (an enzyme related to ketone body utilization) in oxidative muscle. SCOT messenger was slightly more abundant in oxidative muscle of lean chickens but not in glycolytic muscle. In conclusion, the regulation of fatty acid oxidation is probably not impaired in fat chicken. The absence of fasting stimulation of M-CPT1 mRNA expression, which is at variance with the situation observed in mammals, suggests that during fasting, chicken muscles preferentially use ketone bodies as fuel, at least in the short term

The effects of age (from 1 day post-hatch to 98 days of age) and feeding levels (feed restriction followed by overfeeding v. ad libitum feeding) on lipid deposition in breast muscle (quantity and quality, localisation) of mule ducks were determined in relation to muscle energy metabolism (glycolytic and oxidative), plasma levels of lipids, glucose and insulin, and muscle capacity for lipid uptake (characterised by lipoprotein lipase (LPL) activity). Two periods were defined for age effects on intramuscular lipids in breast muscle: 2 1 to 42 days of age when lipids (mainly phospholipids and cholesterol provided by egg yolk) stored in the adipocytes during embryonic life were transferred to the muscle fibres and used for growth and energy requirements, 2 42 to 98 days of age when the muscle again stored lipids (mainly triglycerides provided by liver lipogenesis), first in fibres and then in adipocytes. Plasma glucose and insulin levels were not affected by age. Plasma levels of lipids and LPL activity in breast muscle were high at 1 and 14 days of age and then decreased, remaining stable until 98 days of age. Energy metabolism activity in the breast muscle (mainly glycolytic activity) increased with age. Feed restriction, corresponding to 79% of ad libitum intake, applied between 42 and 75 days of age only resulted in decreases in plasma insulin concentration and total lipid content of breast muscle, mainly affecting triglyceride and mono-unsaturated fatty acid (MUFA) levels. Overfeeding increased plasma levels of insulin and lipids while glycaemia remained stable. LPL activity and total lipid levels increased in breast muscle, mainly induced by deposition of triglycerides and MUFA occurring particularly during the 2nd week of this period. Glycolytic energy metabolism decreased. In response to age or feeding levels, muscle lipid levels and composition reflect plasma lipid levels and composition and high muscle lipid levels stimulate oxidative energy metabolism.

We conducted a study to evaluate the effects of intramuscular fat levels on the sensory characteristics of duck breast meat. Combining duck genotypes (Muscovy, Pekin, and their crossbreed hinny and mule ducks) and feeding levels (overfeeding between 12 and 14 wk of age vs. ad libitum feeding) enabled us to obtain a wide range of lipid levels in breast muscle. The average values were between 2.55 and 6.40 g per 100 g of muscle. Breast muscle from overfed ducks showed higher lipid and lower water levels than breast muscle from ducks fed ad libitum. Muscle from the overfed ducks was also paler in color and exhibited greater yellowness and cooking loss values. Juiciness was judged lower and flavor more pronounced in overfed ducks. Muscovy ducks exhibited higher breast weight and lower lipid levels than the other genotypes. At the other extreme, Pekin ducks exhibited the highest lipid levels and the lowest breast weights; values for these criteria were intermediate in hinny and mule ducks. Breast muscle of Muscovy ducks was paler, less red, and more yellow than that of other genotypes. Breast muscle of Pekin ducks exhibited the lowest values for lightness, yellowness, and energy necessary to shear meat, as well as the highest cooking loss values, and was judged more tender, juicy and less stringy than that of other genotypes. In contrast, scores for breast muscle of Muscovy ducks were the lowest for tenderness, juiciness, and flavor, and the highest for stringiness. Breast muscle of hinny and mule ducks scored the highest values for redness. Hinny ducks also scored the highest values for flavor. Genotype exerted a higher effect on the sensory quality of breast muscle than did feeding levels. Finally, increasing lipid levels in breast muscle increased lightness, yellowness, cooking loss, tenderness, and flavor, with correlation coefficients of 0.49, 0.47, 0.54, 0.43, and 0.28, respectively. However, breast meat color and tenderness were mainly influenced by genotype.

We evaluated the effects of genotype (Muscovy, Pekin and their crossbreed hinny and mule ducks) and feeding levels (overfeeding between 12 and 14 weeks of age vs ad libitum feeding) on energy metabolism and lipid deposition in breast muscle of ducks. Samples of breast muscle (Pectoralis major) were collected at 14 weeks of age from 8 birds per group. Overfeeding induced an accumulation of lipids in breast muscle (1.5- to 1.7-fold, depending on genotype) mainly induced by triglyceride deposition. It also induced a considerable increase in the amounts (expressed as g/100 g of tissue) of saturated and mono-unsaturated fatty acids (SFA, MUFA), while the amounts of poly-unsaturated fatty acids (PUFA) remained unchanged in hinny and Muscovy ducks or slightly increased in Pekin and mule ducks. In breast muscle, overfeeding decreased the activity of the main enzymes involved in lipogenesis from glucose (glucose-6-phosphate dehydrogenase, G6PDH, malic enzyme, ME, acetyl CoA carboxylase, ACX). Lipoprotein lipase (LPL) activity in Pectoralis major muscle was also significantly decreased (− 21%). The ability of muscle tissues to catabolize long-chain fatty acids, as assessed by β-hydroxyacyl CoA dehydrogenase (HAD) activity, was increased in Pectoralis major muscle, as was cytochrome- c oxidase (COX) activity. Hybrid and Pekin ducks exhibited higher levels of ACX and LPL activity in Pectoralis major muscle than Muscovy ducks, suggesting a greater ability to synthesise lipids in situ , and to take up circulating lipids. Total lipid content in breast muscle of hybrid and Pekin ducks was higher than in that of Muscovy ducks. In hybrid and Pekin ducks, lipid composition of breast muscle was characterized by higher amounts of triglycerides, SFA and MUFA than in Muscovy ducks. Finally, oxidative metabolism was greater in Pectoralis major muscles of hybrid and Pekin ducks than in Muscovy ducks, suggesting an adaptative strategy of muscle energy metabolism according to lipid level.

This study was conducted to evaluate the effects of genotype (Muscovy, Pekin and their crossbred hinny and mule ducks) and overfeeding (14 days from 12 weeks of age) on the quantity and quality of lipid deposition in adipose and muscle tissue in ducks. Samples of muscles (Pectoralis major and Iliotibialis superficialis) and abdominal fat were collected at 14 weeks of age to determine lipid levels, lipid classes and fatty acid composition. By comparison with the other genotypes, Pekin ducks exhibited higher amounts of abdominal fat and higher lipid levels in muscles (+105 and +120% in P. major and Iliotibialis superficialis, respectively) by comparison with Muscovy ducks. By comparison with other genotypes, Muscovy ducks exhibited the lowest triglyceride and phospholipid levels in muscles and Pekin ducks the highest levels. Muscovy ducks also showed the lowest cholesterol levels in I. Superficialis muscles. Muscovy ducks exhibited the highest levels of saturated fatty acids (SFA) and poly-unsaturated fatty acids (PUFA) in muscle and adipose tissues and the lowest levels of mono-unsaturated fatty acids (MUFA), and Pekin ducks exhibited the reverse. For all these parameters, the crossbred ducks always presented intermediate values. Overfeeding induced an accumulation of lipids in adipose and muscle tissues (1.2- to 1.7- fold, depending on muscle type and genotype). This increase was higher in P. major than in I. superficialis muscles. The increase in the amount of abdominal fat was 1.7- to 3.1-fold, depending on genotype. This increase in lipid levels in peripheral tissues was mainly induced by triglyceride deposition. Finally, it induced a considerable increase in proportions of MUFA (particularly oleic acid) (expressed as % of total fatty acids) at the expense of PUFA (particularly arachidonic acid) and SFA. However, the amounts (expressed as g per 100 g of tissue) of SFA and MUFA increased in tissues while the amounts of PUFA remained unchanged in muscles and decreased in abdominal fat. The quantity and quality of fat deposition in peripheral tissues depends on the liver's ability to synthesise and also to export lipids. lipids / fatty acids / meat / muscles / ducks

We evaluated the effects of genotype (Muscovy, Pekin and their crossbreed hinny and mule ducks) and feeding levels (overfeeding between 12 and 14 weeks of age vs ad libitum feeding) on liver ability for lipogenesis and lipid secretion in ducks. Samples of liver and blood were collected at 14 weeks of age from 8 birds per group. Plasma levels of insulin was considerably increased in overfed ducks (1.9-fold), stimulating the hepatic activity of the main enzymes involved in lipogenesis from glucose (glucokinase, GK, glucose-6-phosphate dehydrogenase, G6PDH, malic enzyme, ME, acetyl CoA carboxylase, ACX), while cytochrome-c oxidase (COX) activity, indicating overall oxidation ability of energy-yielding substrates, remained unchanged. Plasma levels of triglycerides, phospholipids and total cholesterol were therefore increased (1.9, 3.7, 1.6 and 1.6-fold, respectively). Glycaemia also significantly increased (+8%). Pekin ducks exhibited higher levels of GK and G6PDH activity in the liver than Muscovy ducks, suggesting a greater ability to use glucose consistent with their lower glycaemia. Muscovy ducks had greater ACX activity, suggesting greater ability to synthesise lipids. However, plasma lipid levels were much higher in Pekin ducks than in Muscovy ducks, suggesting a greater ability to export lipids from the liver. Values for the different criteria measured in this study were intermediate or similar in hinny and mule ducks to those of parental species. The high values for GK, G6PDH, ME and ACX activity in hybrid ducks enabled them to produce heavy fatty livers with the same chemical and lipid composition as Muscovy ducks and characterised by high amounts of triglycerides (around 96% of total lipids), and saturated and mono-unsaturated fatty acids.