Bien que la consommation de viande bovine ait diminué au cours des dernières années au niveau européen, la France demeure le premier producteur et consommateur de l’Union européenne. La filière française se distingue par la diversité de ses productions qui s’appuient sur des types d’animaux divers : vaches, génisses, taurillons et boeufs de diverses races et conduits dans différents systèmes de production. Cette diversité est à l’origine de qualités sensorielles et nutritionnelles variées. L’objectif de cet article est de faire le point sur les principales qualités demandées à la viande bovine et de présenter les questions de recherches majeures.

Marbling and rib composition are important attributes related to carcass yields and values, beef quality, consumer satisfaction and purchasing decisions. An open-access computer image analysis method based on a fresh beef rib image captured under nonstandardized and uncontrolled conditions was developed to determine the intramuscular, intermuscular and total fat content. For this purpose, cross-section images of the 5th-6th rib from 130 bovine carcasses were captured with a Galaxy S8 smartphone. The pictures were analyzed with a program developed using ImageJ open source software. The 17 processed image features that were obtained were mined relative to gold standard measures, namely, intermuscular fat, total fat and muscles dissected from a rib and weighed, and intramuscular fat content (IMF - marbling) determined by the Soxhlet method. The best predictions with the lowest prediction errors were obtained by the sparse partial least squares method for both IMF percent and rib composition and from a combination of animal and image analysis features captured from the caudal face of the 6th rib captured on a table. These predictions were more accurate than those based on animal and image analysis features captured from the caudal face of the 5th rib on hanging carcasses. The external-validated prediction precision was 90% for IMF and ranged from 71 to 86% for the total fat, intermuscular and muscle rib weight ratios. Therefore, an easy, low-cost, user-friendly and rapid method based on a smartphone picture from the 6th rib of bovine carcasses provides an accurate method for fat content determination.

The aim of study was to investigate the relationships between the characteristics of cull beef cows in the Rouge des Prés breed, finishing practices and physicochemical characteristics and sensory traits of Longissimus thoracis (LT) and Rectus abdominis (RA) muscles from 111 cows. On the basis of our surveys, which qualify at cow level the animal characteristics and finishing diet, clusters of cull cows and finishing practices are created and their effects tested on LT and RA meat quality. Old and heavy cows with good suckling ability (95 months, 466 kg and 7.1/10) are characterized by LT with larger fibers, and higher intramuscular fat content and fat-to-muscle ratio. Young and heavy cows with low suckling ability (54 months, 474 kg and 4.4/10) are characterized by LT and RA with lower MyHC IIx and higher MyHC IIa and MyHC I proportions. MyHC IIx and IIa proportions are lower and a* and b* color indices higher when cows are finished on pasture, probably related to grass diet and physical activity. The fat-to-muscle ratio is higher without any effect on the intramuscular fat content when cows are finished over a short period (107 days) with a high level of concentrate (9.7 kg/day). The opposite effect is observed over a long period (142 days) with a low level of concentrate (5.8 kg/day), confirming the interaction effect between finishing duration and amount of energy concentrate on the allotment of adipose tissue deposit.

Cet article fait reference a une etude publiee en fin d’annee 2016 dans la revue Meat Science (122, 163-172). Afin de trouver un compromis entre les attentes des producteurs, des transformateurs et des consommateurs, les auteurs ont cherche a determiner dans quelle mesure il est possible de piloter les performances des animaux par le biais des pratiques d’elevage, tout en preservant les qualites sensorielles et la valeur sante des viandes. Pour cela, une methode statistique innovante a ete utilisee : la classification de variables. Les donnees de 71 taurillons du projet europeen ProSafeBeef ont ete organisees en 3 jeux de donnees ca racterisant respectivement les performances animales (36 variables), les qualites sensorielles (29 variables) et la valeur nutritionnelle des viandes (32 variables). Par la construction de 5 index synthetiques pour chaque element du triptyque (combinaisons lineaires d’un sous-ensemble de variables constituant un pool omogene), la methode a permis de supprimer l’information redondante et ainsi de reduire l’information des 97 variables en 15 index synthetiques. Un second regroupement de variables a ensuite ete realise sur ces 15 index synthetiques afin de mettre en evidence les proximites entre les 3 jeux de donnees. L’analyse a montre qu’il n’existe pas d’opposition entre efficience animale et valeur nutritionnelle des viandes. Il est donc possible d’obtenir des animaux efficients (c’est-a-dire avec de meilleurs gains de poids et d’efficacite alimentaire) associant des carcasses a haute valeur bouchere (correspondant a un meilleur developpement musculaire) et des viandes relativement riches en acides gras polyinsatures. En revanche, l‘efficience alimentaire et le developpement musculaire sont apparus negativement correles avec les qualites sensorielles des viandes (notamment la tendrete et l’appreciation globale). La classification de variables est une methode d’analyse de donnees frequemment employee dans certains domaines mais elle n’avait jamais ete utilisee en sciences animales. D’apres les resultats obtenus, cette approche pourrait s’averer etre un outil efficace pour integrer differents concepts dans un pilotage optimise de l’elevage pour les productions animales.

The potential of multi-spectral visible-near infrared imaging to discriminate beef meat muscles in relation with their type and animal origin was examined in the present study. Two hundred forty muscles of three types (longissimus thoracis, biceps femoris, and semimembranosus) were obtained from the carcasses of three types of animals, two late-maturing cattle types of animals (Limousin and Blond d'Aquitaine) that grow slowly and deposit more muscles and less fat, compared to one early-maturing cattle types of animals (Angus) which tends to have muscles richer in collagen and in intramuscular fat. Two hundred forty cube images were collected with nineteen Ligth Emitting Diodes (405 to 1050 nm) using the Videometer Lab2 device. The image cubes were processed in order to extract image mean spectra and image shape features from co-occurrence and difference of histogram matrices. The results of the partial least square discriminant analysis performed on image texture features and spectral data show a maximum ranging from 63.5 to 83% of good classification depending on the muscle and breed considered. This study demonstrated the promising potential of the visible-near infrared multi-spectral imager to characterize beef meat muscles based on muscle type and its animal origin.

Eating quality of the same meat samples from different animal types cooked at two end-point cooking temperatures (55°C and 74°C) was evaluated by trained panels in France and the United Kingdom. Tenderness and juiciness scores were greater at 55°C than at 74°C, irrespective of the animal type and location of the panel. The UK panel, independently of animal type, gave greater scores for beef flavour (+7 to +24%, P<0.001) but lower scores for abnormal flavour (-10 to -17%, P<0.001) at 74°C. Abnormal flavour score by the French panel was higher at 74°C than at 55°C (+26%, P<0.001). Irrespective of the data set, tenderness was correlated with juiciness and beef flavour. Overall, this study found that cooking beef at a lower temperature increased tenderness and juiciness, irrespective of the location of the panel. In contrast, cooking beef at higher temperatures increased beef flavour and decreased abnormal flavour for the UK panelists but increased abnormal flavour for the French panel.

Background The immobilization-induced tibialis anterior (TA) muscle atrophy worsens after cast removal and is associated with altered extracellular matrix (ECM) composition. The secreted protein acidic and rich in cysteine (Sparc) is an ECM component involved in Akt activation and in beta-catenin stabilization, which controls protein turnover and induces muscle regulatory factors (MRFs), respectively. We hypothesized that ECM alterations may influence these intracellular signalling pathways controlling TA musclemass.Methods Six-month-old Wistar rats were subjected to hindlimb cast immobilization for 8 days (I8) or not (I0) and allowed to recover for 1 to 10 days (R1-10).Results The TA atrophy during remobilization correlated with reduced fibre cross-sectional area and thickening of endomysium. mRNA levels for Sparc increased during remobilization until R10 and for integrin-alpha 7 and -beta 1 at I8 and R1. Integrin-linked kinase protein levels increased during immobilization and remobilization until R10. This was inversely correlated with changes in Akt phosphorylation. beta-Catenin protein levels increased in the remobilized TA at R1 and R10. mRNA levels of the proliferative MRFs (Myf5 and MyoD) increased at I8 and R1, respectively, without changes in Myf5 protein levels. In contrast, myogenin mRNA levels (a terminal differentiation MRF) decreased at R1, but only increased at R10 in remobilized muscles, as for protein levels.Conclusions Altogether, this suggests that the TA inefficiently attempted to preserve regeneration during immobilization by increasing transcription of proliferative MRFs, and that the TA could engage recovery during remobilization only when the terminal differentiation step of regeneration is enhanced.

– Relationships with CIE-L*a*b* colour traits of protein biomarkers known to be related to tenderness were studied in Longissimus thoracis muscles from 21 French Blonde Aquitaine young bulls. L*, a* and b* coordinates were correlated with 9, 5 and 8 of the 21 biomarkers, respectively. Regression models explained between 47 and 65% of the variability between individuals in L*a*b* values. Results suggest that development of colour and tenderness may share common biological pathways. They further show that inducible Hsp70s and µ-calpaïn influence the three colour parameters interactively.

Many studies on color biochemistry and protein biomarkers were undertaken in post-mortem beef muscles after ≥24 hours. The present study was conducted on Longissimus thoracis muscles of 21 Blond d'Aquitaine young bulls to evaluate the relationships between protein biomarkers present during the early post-mortem and known to be related to tenderness and pH decline and color development. pH values at 45 min, 3 h, and 30 h post-mortem were correlated with three, seven, and six biomarkers, respectively. L*a*b* color coordinates 24 h post-mortem were correlated with nine, five, and eight protein biomarkers, respectively. Regression models included Hsp proteins and explained between 47 and 59% of the variability between individuals in pH and between 47 and 65% of the variability in L*a*b* color coordinates. Proteins correlated with pH and/or color coordinates were involved in apoptosis or had antioxidative or chaperone activities. The main results include the negative correlations between pH45 min, pH3 h, and pHu and Prdx6, which may be explained by the antioxidative and phospholipase activities of this biomarker. Similarly, inducible Hsp70-1A/B and μ-calpain were correlated with L*a*b* coordinates, due to the protective action of Hsp70-1A/B on the proteolytic activities of μ-calpain on structural proteins. Correlations existed further between MDH1, ENO3, and LDH-B and pH decline and color stability probably due to the involvement of these enzymes in the glycolytic pathway and, thus, the energy status of the cell. The present results show that research using protein indicators may increase the understanding of early post-mortem biological mechanisms involved in pH and beef color development.

Meat-grain-size (MGS) assessment is an empirical method for the early prediction of meat quality, a larger grain being synonymous with higher meat tenderness. The objective was to characterize 4 muscles (longissimus thoracis LT; rectus abdominis RA; longus colli LC; diaphragma D) of 5 coarse and 5 fine carcasses in terms of MGS in order to establish a link between muscular physicochemical properties and carcass MGS score. All comparisons were made of samples with similar fat content. The broiled sample hardness (shear force) was significantly higher for the coarse group than for the fine group (7.20 vs 5.89 kg; RA). Higher collagen content (27.94 vs 24.87 mg/g of dry matter in LT muscle; 15.86 vs 13.13 mg/g of dry matter in D muscle), higher oxidative metabolism (cytochrome-c oxidase; LT and D) but also higher glycolytic metabolism (lactate dehydrogenase; LT) were also observed in the coarse groups. Not all the muscles react in a similar way depending on the MGS group. Nevertheless, significant results are constant from one muscle to another, the RA being the only muscle for which the difference in hardness between the two groups is significant.

Previous proteomic analyses established a list of proteins biomarkers of beef tenderness. The present study quantified the relative abundance of 21 of these proteins by dot-blot technique in the Longissimus thoracis and Semitendinosus muscles of 71 young bulls from three breeds. Aberdeen Angus (AA), Limousin (LI), and Blond d'Aquitaine (BA). For both muscles overall tenderness was estimated by sensory analysis; shear force was measured with a Warner-Bratzler instrument, and an i ndex combining sensory and mechanical measurements was calculated. Multiple regressions based on relative abundances of these proteins were used to propose equations of prediction of the three evaluations of tenderness. HSP70 1B appeared to be a heavy chian IIx, and small heat shock proteins (Hsp27, Hsp20; and alpha B-crystallin) were related to tenderness but inversely according to the muscle and breed. The results demonstrate that prediction of tenderness must take into account muscle characteristics and animal type.

The assessment of the meat "grain" size is an empirical method used by some butchers in France to predict the tenderness of meat: the finer the grain the higher the quality. Four studies are presented here. After a characterization of this notion using an ethnological approach, two grids were built to objectivate the way of evaluating grain of meat on live animals and carcasses. The second aim was to characterize the main muscles used by the experts to rate the grain of meat. The last aim was to establish the relation between the score of meat grain estimated on the carcass and the tenderness of the longissimus thoracis muscles estimated by sensory evaluations. A group of 16 criteria were identified on the carcass as effective to anticipate overall "grain of meat" score. "Fine grain" carcasses were associated with lower lipid content than "coarse grain" in longissimus thoracis muscles, leading to significantly lower scores of flavor intensity without any impact on juiciness scores. No significant relation appeared between grain of meat and tenderness. The shear force needed to cut a broiled sample was found significantly higher for "coarse grain" carcasses than for "fine grain" ones. The total collagen in the "coarse grain" group was significantly higher than those from the "fine grain" group without any impact on collagen solubility. Taken together, these results allow hypothesizing that "fine grain" could have a positive impact on meat quality traits. The differences underlined are nevertheless very muscle-dependant and remain to be confirmed in larger trials.

No matter which production system is considered (5% milk farms, 95% meatfarms), the Salers breed of cattle carries a strong image. Our work aims at showing that the development of the main territory in which the breed is found may rely on specific and identified products afforded by the breed. Multidisciplinary research (animal science, economics, food quality) and different methods (surveys, follow-up, and experimentation) were implemented. The experiments focused on the control of various types of production (milk, carcasses) and on a detailed description of the products (meat, cheese), given the attributes and the special behaviour of the animals. A before-weaning feeding approach favouring milk and forage later proves more efficient for finishing the young Salers male (15 months). The meat from these young bulls is clear, classified as mid-range quality, and can be sold in supermarkets. Parallel observations were made on farms and specific protein markers of juiciness were identified. Milk from Salers cows differs from that of Holstein especially in the nature of the fatty acids. Calf suckling before milking reinforces the differences. Cheeses made with raw milk from the breed differ in their textures and flavours. The cow must however be milked with her calf and the level of labour required impedes economic valorisation of the breed. Consumer surveys have confirmed the strong image of the breed that has a good potential for commercial development. Willingness to pay for identified products, however, is stronger for cheese (up to 30%) than for meat (up to 10%). Recognized qualities of products identified as issued from Salers cattle and originality in production systems can bring significant gains to various local actors, which can be considered as territorial rents.

L'évaluation du « grain de viande » est une appréciation subjective, utilisée par certains chevillards et bouchers pour sélectionner et orienter les carcasses, un grain extrêmement fin étant synonyme de qualité. Pour évaluer la pertinence de cette notion quatre études ont permis i) d’objectiver la notion de grain de viande par une approche ethnologique, ii) de formaliser ce savoir-faire dans une grille de notation en vif et en carcasse, iii) d’évaluer les propriétés physicochimiques des quatre muscles utilisés par les experts pour juger une carcasse, et iv) d’évaluer l’existence d’un lien entre l’évaluation du grain de viande et la qualité sensorielle des viandes. Les seize indicateurs consignés dans la grille établie sur la carcasse sont répétables et facilement utilisables en abattoir. Sur le muscle longissimus thoracis, les grains fins ont été caractérisés par des teneurs en lipides intramusculaires significativement plus faibles que les grains grossiers, conduisant à des notes d’intensité de flaveur également significativement plus faibles, mais sans répercussions sur les notes de jutosité. Il n’est pas apparu de différence significative de tendreté entre les muscles à grains fins et grossiers. Au niveau physicochimique, le grain fin a été associé à des muscles nécessitant une moindre force de cisaillement sur la viande cuite et présentant une moindre teneur en collagène, sans différence sur sa solubilité, laissant supposer un effet favorable sur les propriétés sensorielles. Les écarts sont cependant très dépendants du muscle étudié et méritent d’être confirmés à plus grande échelle.

Different criteria of sustainability were compared to evaluate three bull-fattening systems using contrasted diets based on hay, maize silage or concentrate. Environmental impacts were determined using life cycle assessment, economic margin was evaluated from feeding costs and animal price, and animal welfare related to diet was appreciated through digestive discomfort and health value of produced meat through fatty acid composition. The results show that diet ranking depends on the criteria considered, and that the mode of expression of the criteria is of major importance.

Three muscles (Longissimus thoracis, Semimembranosus, Biceps femoris) of 40 young bulls from 3 breeds were used to quantify structural characteristics of bovine connective tissue by image analysis, with both macroscopic and microscopic approaches. Collagen and proteoglycan content was also investigated. Perimysium occupied a greater area (8 vs 6%), and was wider (42 vs 2 μm) and shorter per unit area (1.9 vs 30 mm mm(-2)) than endomysium. Perimysium and endomysium from Longissimus were thinner, less ramified than in Biceps. Longissimus showed less total collagen and cross-linking and more proteoglycans (P<0.0001) than Biceps muscle. Blond d'Aquitaine perimysium occupied less area, was more ramified and muscles contained less collagen, cross-linking and more proteoglycans than Angus (P<0.001). Limousin was intermediate. High proteoglycan content in muscle containing less total collagen suggested a complementarity between these molecules. They might influence mechanical properties of intramuscular connective tissue. This was especially true given that proteoglycans and total collagen were negatively and positively linked with structural parameters, respectively.

The BIF-Beef (Beef Integrated and Functional Biology) database contains animal, carcass, muscle and meat data (331,745 entries) collected from 43 experiments over the last 20 years and a great number of variables (621) characterising muscles (fat and collagen contents, cross-section and types of fibres, metabolic activity), making it a relevant tool to relate muscle characteristics to beef quality. Wide variation was observed in all described traits according to muscle type, sex and breed. The BIF-Beef database was mainly composed of data from young bulls of late-maturing beef breeds, which is why live weight and carcass weights of the animals were greater, and beef was leaner and lighter than results from other existing databases. Average cross-sectional area of fibres was greater in Semitendinosus than in Longissimus thoracis muscle and, for Longissimus, greater in steers than in young bulls. Intramuscular fat content was in descending order: Charolais > Limousin > Blond d'Aquitaine and females > steers > young bulls. Semitendinosus muscle was less oxidative and contained more collagen than Longissimus muscle. Collagen content in Longissimus was higher in Charolais than in Blond d'Aquitaine and Limousin young bulls. Within the Charolais breed, collagen content in Longissimus was higher in young bulls and steers than in females. Longissimus samples from young bulls were less tender than from females. Based on the above results, this database is a prerequisite for meta-analysis of relationships between muscle characteristics and beef quality in the European context.