Les aliments pour l’homme, outre leurs aspects nutritionnels de couverture des besoins, ont acquis depuis peu une valeur santé. Face à ce phénomène, de nouveaux besoins de connaissances concernant les constituants des aliments sont apparus. Cet article a pour objet de montrer les points forts et les lacunes dans les connaissances relatives à la valeur nutritionnelle de la viande de lapin. 50 publications ont été sélectionnées. Pour des lapins aux âges et poids commerciaux d’abattage, les teneurs en protéines (21 + 1,5 % de viande fraîche), eau (72,5 + 2,5 % de viande fraîche) et minéraux totaux (1,2 + 0,1 % de viande fraîche) sont similaires dans les différents travaux et ne nécessitent pas d’autres investigations. Les principales causes de variations de la teneur en lipides (5 + 3,3 % de viande fraîche) sont connues et bien décrites (région anatomique et alimentation principalement). La viande de lapin est pauvre en sodium (49 mg/100 g) mais riche en phosphore (277 mg/100 g). Les teneurs en certains éléments tels le fer (1,4 mg/100 g), le cuivre ou le sélénium ne sont pas suffisamment bien établies. Par ailleurs les teneurs d’autres oligo-éléments n’ont à notre connaissance jamais été évaluées. Enfin, les données disponibles semblent indiquer que la viande de lapin montre un profil global en vitamines proche de celui observé chez le poulet. Il est cependant nécessaire de confirmer ces observations. La viande de lapin présente une teneur en cholestérol relativement basse comparativement aux autres viandes de 59 mg/100g et un ratio en acides gras oméga 6 / oméga 3 avantageux de 5,9. L’équilibre en acide gras de la viande de lapin, animal monogastrique et herbivore, montre par ailleurs une remarquable plasticité en fonction de l’équilibre en acide gras de la ration.

Dietary change alters the ruminal ecosystem and can be regarded as a disturbance. Studying the response to a disturbance can help us understand the behavior of the ecosystem. Our work is concerned with the response of the ruminal ecosystem (composition and activities) during the application of repeated dietary disturbances to 6 dry Holstein cows. For 2 mo, the cows received a hay-based diet [experimental period (EP) 0], followed by 3 EP of successive changes (EP 1, 2, and 3) comprised of 2 parts: the first (10 d) with a corn silage-based diet and the second (25 d) with a hay-based diet. The measurements and samplings were done on the last days of EP 0 and of each part of EP 1 through 3, with the results of EP 0 used as covariables in the statistical models. The physicochemical measurements (pH and redox potential) and the fermentation variables (VFA, ammonia) were determined hourly between the morning and evening meals (n = 8 measurements/d). Samples of ruminal contents were taken 3 h after the morning meal to determine enzymatic activity [amylase, carboxymethyl cellulase (CMCase), and xylanase], to count the main protozoan genera and to quantify the bacteria by quantitative PCR, and to determine its structure by the capillary electrophoresis single-strand conformation polymorphism process. The pH fell for the corn silage-based diet with the EP (P < 0.05) but not for the hay-based diet. The VFA concentration decreased for both diets with the EP (P < 0.001), with the primary changes in acetate and propionate. The ammonia concentration increased for the corn silage-based diet with the EP (P < 0.05), whereas for the hay-based diet the highest value was observed for EP 2 (P < 0.05). The total quantity of bacteria decreased between EP 1 and 3 (P < 0.05) for both diets. The structure of the bacterial community was not affected by the disturbances for the corn silage-based diet, whereas for the hay-based diet large differences were evident between EP 1 and 3 (P < 0.05) and 2 and 3 (P < 0.01). The number of protozoa increased over the EP, with a more marked effect for the corn silage-based diet (diet × EP interaction, P < 0.05). The specific amylase, CMCase, and xylanase activities decreased over the EP for both diets (P < 0.05). The dietary changes applied in our experiment involved strong modifications of the ruminal ecosystem and alterations of ruminal fermentation and enzymatic activities. These alterations were reinforced with the repetition of the dietary changes.

-The effects of selection for growth rate on weights and qualitative carcass and muscle traits were assessed by comparing two lines selected for live body weight at 63 days of age and a cryopreserved control population raised contemporaneously with generation 5 selected rabbits. The animals were divergently selected for five generations for either a high (H line) or a low (L line) body weight, based on their BLUP breeding value. Heritability (h 2 ) was 0.22 for 63-d body weight (N = 4754). Growth performance and quantitative carcass traits in the C group were intermediate between the H and L lines (N = 390). Perirenal fat proportion (h 2 = 0.64) and dressing out percentage (h 2 = 0.55) ranked in the order L < H = C (from high to low). The weight and cross-sectional area of the Semitendinosus muscle, and the mean diameter of the constitutive myofibres were reduced in the L line only (N = 140). In the Longissimus muscle (N = 180), the ultimate pH (h 2 = 0.16) and the maximum shear force reached in the Warner-Braztler test (h 2 = 0.57) were slightly modified by selection.rabbit / growth / selection / genetic parameters / meat quality

Intestinal organoids are increasingly being used to study the gut epithelium for digestive disease modeling, or to investigate interactions with drugs, nutrients, metabolites, pathogens, and the microbiota. Methods to culture intestinal organoids are now available for multiple species, including pigs, which is a species of major interest both as a farm animal and as a translational model for humans, for example, to study zoonotic diseases. Here, we give an in-depth description of a procedure used to culture pig intestinal 3D organoids from frozen epithelial crypts. The protocol describes how to cryopreserve epithelial crypts from the pig intestine and the subsequent procedures to culture 3D intestinal organoids. The main advantages of this method are (i) the temporal dissociation of the isolation of crypts from the culture of 3D organoids, (ii) the preparation of large stocks of cryopreserved crypts derived from multiple intestinal segments and from several animals at once, and thus (iii) the reduction in the need to sample fresh tissues from living animals. We also detail a protocol to establish cell monolayers derived from 3D organoids to allow access to the apical side of epithelial cells, which is the site of interactions with nutrients, microbes, or drugs. Overall, the protocols described here is a useful resource for studying the pig intestinal epithelium in veterinary and biomedical research.