Review: Will "cultured meat" transform our food system towards more sustainability?

Our agri-food system today should provide enough healthy food of good quality for the growing human population. However, it should also preserve natural resources and better protect livestock. In this context, some FoodTech companies are developing a disruptive approach: cell culture for in vitro food production of "meat" but this technology is still at the research and development stage. This article will highlight its development, the technologies used and the stakeholders involved (Part 1), its potential environmental impacts (Part 2) but also regulatory, social and ethical issues (Part 3). This article aims to shed light throughout the manuscript on two major controversies related to "cultured meat". The first controversy is related to its ethical aspects, which includes different points: its potential to reduce animal suffering and therefore to improve animal welfare, the future values of our society, and a trend towards food artificialisation. The second controversy includes environmental, health and nutritional issues, in relation to the characteristics and quality of "cultured meat" with an important question: should we call it meat? These two controversies act in interaction in association with related societal, legal and consequently political issues. Answers to the various questions depend on the different visions of the World by stakeholders, consumers and citizens. Some of them argue for a moderate or a strong reduction in livestock farming, or even the abolition of livestock farming perceived as an exploitation of farm animals. Others just want a reduction of the current much criticised intensive/industrial model. Compared with other potential sustainable solutions to be implemented such as reduction of food losses and waste, new food consumption habits with less proteins of animal sources, sustainable intensification, development of agroecological livestock production, or the development of the market for other meat substitutes (proteins from plants, mycoproteins, algae, insects, etc.), "cultured meat" has an uncertain future.

The Meat Standards Australia carcass grading site affects assessment of marbling and prediction of meat-eating quality in growing European beef cattle

The lack of consumer feedback on beef eating quality contributes to reduced beef consumption in Europe. The Meat Standards Australia (MSA) grading scheme can assess the palatability of beef carcasses usually graded at the 10th thoracic vertebrae. However, the European beef industry relies on late-maturing breeds usually cut at the 5th vertebrae due to commercial reasons. Data from 55 young bulls and heifers of late-maturing breeds were collected in an Italian slaughterhouse following the MSA guidelines at both carcass grading sites and sides. Intramuscular fat levels were assessed through two scores and used with other variables to feed the MSA model, which predicts the MSA index, the meat-eating quality scores (MQ4) for 5 muscles and for each carcass grading site × side combination. The scores were analyzed using a mixed linear model. A correlation analysis was conducted to predict the variables measured at the 10th site using their correspondent at the 5th carcass grading site. A stepwise regression was conducted to understand the weight of each measured variable on marbling and MQ4 scores measured both at 5th and 10th carcass grading sites. Results showed significantly higher value for the studied traits at the 5th carcass grading site, while carcass side had no significant impact. The equations had high predictive capability and MSA marbling score played a key role in explaining the variability across carcass grading sites. The differences in marbling and MQ4 scores between the carcass grading sites suggest considering this factor if the MSA grading system will be applied to Europe.

Does transport stress have any effect on carcass quality of Nellore cattle (Bos taurus indicus) in Brazil? - A case study

With the increasing concomitant demands for Brazilian beef and in particular high-quality beef, there is a need for observational studies of the effects of pre- and post-slaughter practices on beef carcass traits. We hypothesized in our case study that pre-slaughter transport of bovines over significant distances would induce stress in animals, and that this would reduce carcass quality because of higher pH resulting from long-distance transportation. To test this hypothesis, 30,230 Nellore carcasses from a private slaughterhouse were evaluated 24 h postmortem. Analysis showed correlations between animal maturity, ultimate pH, distance, and carcass weight. More precisely, there was a slight positive correlation between ultimate pH and weight (but not with transportation distance) and a slight positive correlation between maturity and weight. A linear regression model (R2 = 0.016) failed to show distance having a significant effect on ultimate pH (P = 0.63), while carcass weight significantly affected ultimate pH (P < 0.001) with a low coefficient of 0.0003. Maturity negatively affected ultimate pH also (P < 0.001) but with also a small effect (-0.0008). Results (from 95% confidence intervals of variance of the random effects and of the random errors) showed that the variability within farms was higher than between farms. The linear mixed model showed that maturity had a significant effect on carcass weight value (P < 0.001) with a large coefficient of 2.90. The R2 of the linear mixed model was 46.03%. In conclusion, while weight and maturity both affect ultimate pH, long distances did not significantly impact ultimate pH and therefore the beef quality from Nellore cattle. This could be because of low stress during transport, as well as the physical characteristics of the Nellore breed that favor greater resistance to tropical climatic conditions.

French consumer evaluation of eating quality of Angus x Salers beef: Effects of muscle cut, muscle slicing and ageing

Based on the Meat Standards Australia (MSA) methodology, the objectives of this study were to evaluate the eating quality of grass-fed Angus x Salers beef by French consumers, across different muscle cuts (m. triceps brachii caput longum, m. longissimus dorsi et thoracis and m. rectus abdominis), ageing times (5 and 14 days) and muscle slicing and grilling methods (being distinguished by 2 different sides on the grill), and to further quantify whether the MSA model could predict the eating quality of the meat produced by these lean crossbred animals. The results showed that French consumers can discern significant differences in eating quality traits across muscle cuts but not between ageing times and muscle slicing methods. In this study, the accuracy of eating quality score (MQ4)-assigned MSA grade was 64.5%. Due to the lack of MSA data on these lean crossbred animals, the prediction of eating quality from carcass characteristics was less accurate than usual. However, these results do indicate that the MSA sensory testing protocol, the MQ4 calculation and the MSA quality grades could be used to support a consumer-based quality grading system in France.

Consumer perception of the challenges facing livestock production and meat consumption

With the global meat market growing and intensive livestock farming systems increasing, the impacts of livestock are a growing concern among consumers, further influencing their meat consumption. Understanding consumer perceptions of livestock production is therefore a key issue. This study surveyed 16,803 respondents in France, Brazil, China, Cameroon and South Africa to investigate the different perceptions of the ethical and environmental impacts of livestock production among consumer segments in different countries based on their sociodemographic characteristics. On average, the current respondents in Brazil and China and/or who consume little meat, are female, not in the meat sector and/or more educated, are more likely to think that livestock meat production causes serious ethical and environmental problems; while those in China, France and Cameroon and/or who consume little meat and/or are women, younger, not in the meat sector, and/or more educated, are more likely to agree that reducing meat consumption could be a good solution to these problems. Additionally, an affordable price and sensory quality are the main drivers of food purchases for the current respondents. In conclusion, sociodemographic factors have significant effects on consumer perception of livestock meat production and meat consumption habits. Perceptions of the challenges facing livestock meat production differ between countries in different geographic regions based on social, economic, cultural contexts and dietary habits.

Consumer perception of "artificial meat" in the educated young and urban population of Africa

African's population is expected to grow especially in cities to reach about 2.5 billion in 2050. This will create an unprecedented boom in the demand for animal products over the coming years which will need to be managed properly. Industry stakeholders worldwide have been touting the potential benefits of "artificial meat" in recent years as a more sustainable way of producing animal protein. "Artificial meat" is therefore moving into the global spotlight and this study aimed to investigate how African meat consumers of the coming generations perceive it, i.e., the urban, more educated and younger consumers. Three surveys were conducted with more than 12,000 respondents in total. The respondents came from 12 different countries (Cameroon, Congo, -DRC Democratic Republic of Congo, Ghana, Ivory Coast, Kenya, Morocco, Nigeria, Senegal South Africa, Tanzania and Tunisia). Respondents in this survey prefered the term "artificial meat". This term was therefore used throughout the survey. "Artificial meat" proved to be fairly well known in the surveyed countries as about 64% the respondents had already heard of "artificial meat." Only 8.9% were definitely willing to try "artificial meat" (score of 5 on a scale of 1-5) mostly males between 31 and 50 years of age. Furthermore, 31.2% strongly agreed that "artificial meat" will have a negative impact on the rural life (score of 5 on a scale of 1-5) and 32.9% were not prepared to accept "artificial meat" as a viable alternative in the future but were still prepared to eat meat alternatives. Of all the results, we observed significant differences in responses between respondents' countries of origin, age and education level with interactions between these factors for willingness to try. For instance, the richest and most educated countries that were surveyed tended to be more willing to try "artificial meat." A similar pattern was observed for willingness to pay, except that gender had no significant effect and age had only a small effect. One major observation is that a large majority of respondents are not willing to pay more for "artificial meat" than for meat from livestock.

Should and will "cultured meat" become a reality in our plates?

Produced from proliferating cells in bioreactors with a controlled culture medium, "cultured meat" has been presented by its supporters, who are mainly private actors (start-ups), as a sustainable solution to meet the growing demand for animal proteins without weaknesses of animal husbandry in terms of environmental impact, animal welfare or even health. The aim of this chapter is to take stock of current knowledge on the potential benefits and pitfalls of this novel product. Since robust scientific arguments are lacking on these aspects, there is no consensus on the health and nutritional qualities of "cultured meat" for human consumption and on its potential low environmental impact. In addition, many issues related to the market, legislation, ethics and consumer perception remain to be addressed. The way in which this new product is regarded appears to be influenced by many factors related mainly to its price, as well as to the perception of safety, sensory traits but also environmental and nutritional issues. Therefore, research by universities and public research institutes indicates that "cultured meat" production does not present any major advantages in economic, nutritional, sensory, environmental, ethical or social terms compared to conventional meat. Thus, a more balanced diet by diversifying our sources of plant and animal proteins, consuming other meat substitutes, and reducing food losses and waste appear to be more effective short-term solutions to the urgent need of producing enough food for the growing human population (while reducing environmental degradation and animal suffering).

Transcriptome profiling reveals stress-responsive gene networks in cattle muscles

In meat-producing animals, preslaughter operations (e.g., transportation, mixing unfamiliar animals, food and water deprivation) may be a source of stress with detrimental effects on meat quality. The objective of this work was to study the effect of emotional and physical stress by comparing the transcriptomes of two muscles (M. longissimus thoracis, LT and M. semitendinosus, ST) in Normand cows exposed to stress (n = 16) vs. cows handled with limited stress (n = 16). Using a microarray, we showed that exposure to stress resulted in differentially expressed genes (DEGs) in both muscles (62 DEGs in LT and 32 DEGs in ST, of which eight were common transcription factors (TFs)). Promoter analysis of the DEGs showed that 25 cis transcriptional modules were overrepresented, of which nine were detected in both muscles. Molecular interaction networks of the DEGs targeted by the most represented cis modules helped identify common regulators and common targets involved in the response to stress. They provided elements showing that the transcriptional response to stress is likely to (i) be controlled by regulators of energy metabolism, factors involved in the response to hypoxia, and inflammatory cytokines; and (ii) initiate metabolic processes, angiogenesis, corticosteroid response, immune system processes, and satellite cell activation/quiescence. The results of this study demonstrate that exposure to stress induced a core response to stress in both muscles, including changes in the expression of TFs. These factors could relay the physiological adaptive response of cattle muscles to cope with emotional and physical stress. The study provides information to further understand the consequences of these molecular processes on meat quality and find strategies to attenuate them.

Review: On-farm and processing factors affecting bovine carcass and meat quality

This paper reviews the current state of knowledge on beef carcass and meat quality, with particular emphasis on on-farm and processing factors associated with its high and inconsistent variability. The diversity of livestock systems comes from the diversity of breeds (dairy or beef), ages and gender (bulls, steers, heifers, cull cows) used to produce either mainly beef or beef and milk. In addition, there are factors linked to farming practices (including diet, especially grazing) which significantly influence the sensory, nutritional, technological and extrinsic (such as image) quality attributes of meat. These can become factors of positive differentiation when controlled by the application and certification of technical specifications. Finally, preslaughter (such as stress), slaughter (such as the chilling and hanging method of carcasses) and postslaughter (such as ageing, packaging and cooking) conditions have a strong influence on the microbiological, sensory, technological and image quality attributes of beef. In this review, potential synergisms or antagonisms between the different quality attributes are highlighted. For example, finishing cattle on grass, compared to indoor fattening on a high concentrate diet, has the advantage of producing leaner meat with a higher proportion of omega-3 fatty acids while exhibiting superior oxidative stability, but with the consequence of a darker meat colour and lower productivity, as well as higher seasonality and land surface requirements. Moreover, the control of on-farm factors is often guided by productivity (growth rate, feed conversion ratio) and carcass quality attributes (weight, conformation and fatness). Genetic selection has often been oriented in this direction, without taking other quality attributes into account. Finally, the interactions between all these factors (and especially between on-farm and slaughter or processing factors) are not considered in the quality grading schemes in European countries. This means that positive efforts at farm level may be mitigated or even eliminated by poor slaughtering or processing conditions. All these considerations explain why between-animal variability in quality can be high, even when animals come from the same farming system. The ability to predict the sensory and nutritional properties of meat according to production factors has become a major objective of the supply chain.

Handheld near-infrared spectrometer allows on-line prediction of beef quality traits

The aim of this study was to evaluate the ability of a miniaturized near-infrared spectrometer to predict chemical parameters, technological and quality traits, fatty acids and minerals in intact Longissimus thoracis and Trapezius obtained from the ribs of 40 Charolais cattle. Modified partial least squares regression analysis to correlate spectra information to reference values, and several scatter correction and mathematical treatments have been tested. Leave-one-out cross-validation results showed that the handheld instrument could be used to obtain a good prediction of moisture and an approximate quantitative prediction of fat or protein contents, a*, b*, shear force and purge loss with coefficients of determination above 0.66. Moreover, prediction models were satisfactory for proportions of MUFA, PUFA, oleic and palmitic acids, for Fe and Cu contents. Overall, results exhibited the usefulness of the on-line miniaturized tool to predict some beef quality traits and the possibility to use it with commercial cuts without sampling, carcass deterioration nor grinding and consequent meat products' loss.

Brazilian Consumers' Attitudes towards So-Called "Cell-Based Meat"

The main goal of this online survey was to investigate the attitudes of Brazilians towards “cell-based meat”, which has become the subject of great scientific and media enthusiasm. The answers of 4471 respondents concluded that 46.6% of them thought “cell-based meat” was promising and acceptable. More than 66% would be willing to try this novel product compared to 23% who expressed reluctance to do so. Nearly 40% of the total respondents did not want to eat “cell-based meat” regularly at all, whereas 29%, 43.2%, and 39.9% were willing to eat it regularly in restaurants, at home, and/or in ready-made meals, respectively. However, the majority of respondents (71%) were keen to pay much less for “cell-based meat” than conventionally produced meat (or even nothing at all), compared to 24.3% who were willing to pay the same price as conventional meat, whereas only 4.8% were willing to pay more. Approximately 51% of them considered that “cell-based meat” should not be called “meat” for marketing purposes. Job, monthly income, age, and gender were major factors impacting consumer acceptance. Meat professionals and consumers with higher incomes were less willing to eat “cell-based meat” regularly. Women (especially younger women) were the most concerned about the ethical and environmental issues related to meat production and were the most convinced that reducing meat consumption could be a good solution to the meat industry’s problems. Respondents who did not accept “cell-based meat” and did not eat meat substitutes had a negative attitude to this novel food (they considered it absurd and/or disgusting) and did not believe that “cell-based meat” should be called “meat” for marketing purposes. In contrast, the people who thought that “cell-based meat” could be called “meat” perceived it in a rather positive way. These results are important for consumers of meat and meat substitutes and for companies aiming to enter the potential future Brazilian market of “cell-based meat”.

Are Marbling and the Prediction of Beef Eating Quality Affected by Different Grading Sites?

For the European abattoirs, the preferred carcass grading site is at the fifth rib, and cutting at the tenth rib as in Australia could lead to a lower economic value of the carcass. Therefore, the objective of this study was to compare the grading scores of marbling and the meat and fat color on Musculus longissimus thoracis et lumborum (LTL) at the fifth and the tenth thoracic vertebrae. The consequences on the prediction of beef eating quality using the Meat Standards Australia (MSA) grading scheme were also evaluated for cull cows, which produce the majority of beef consumed in France. Carcasses from 208 French cattle, mainly Limousine cows, were graded according to the Australian Beef Carcase Chiller Assessment System (ABCAS) used for the implementation of the MSA system. The results indicate that there was no significant difference in the marbling score, between the fifth and the tenth ribs and hence in the MSA index and in the Global Quality [meat quality (MQ4)] scores calculated from marbling values from either the fifth rib or the tenth rib. However, the meat color at the tenth rib was significantly darker than that at the fifth rib (p < 0.01), and the fat color at the tenth rib was significantly yellower than that at the fifth rib (p < 0.001). The results of this study suggest that the grading of marbling can be conducted on M. LTL at the fifth thoracic vertebrae for routine use of the MSA system in France and, more generally, in Europe. However, further investigation and adjustment would be needed for other critical MSA scores (such as rib fat thickness) while respecting the European carcass quartering practices.

Chinese Consumers' Attitudes and Potential Acceptance toward Artificial Meat

The interest for artificial meat has recently expanded. However, from the literature, perception of artificial meat in China is not well known. A survey was thus carried out to investigate Chinese attitudes toward artificial meat. The answers of 4666 respondents concluded that 19.9% and 9.6% of them were definitely willing and unwilling to try artificial meat respectively, whereas 47.2% were not willing to eat it regularly, and 87.2% were willing to pay less for it compared to conventional meat. Finally, 52.9% of them will accept artificial meat as an alternative to conventional meat. Emotional resistance such as the perception of "absurdity or disgusting" would lead to no willingness to eat artificial meat regularly. The main concerns were related to safety and unnaturalness, but less to ethical and environmental issues as in Western countries. Nearly half of the respondents would like artificial meat to be safe, tasty, and nutritional. Whereas these expectations have low effects on willingness to try, they may induce consumers' rejection to eat artificial meat regularly, underlying the weak relationship between wishes to try and to eat regularly. Thus, potential acceptance of artificial meat in China depends on Chinese catering culture, perception of food and traditional philosophy.

Visible and Near-Infrared Multispectral Features in Conjunction with Artificial Neural Network and Partial Least Squares for Predicting Biochemical and Micro-Structural Features of Beef Muscles

The objective of this study was to determine the potential of multispectral imaging (MSI) data recorded in the visible and near infrared electromagnetic regions to predict the structural features of intramuscular connective tissue, the proportion of intramuscular fat (IMF), and some characteristic parameters of muscle fibers involved in beef sensory quality. In order to do this, samples from three muscles (Longissimus thoracis, Semimembranosus and Biceps femoris) of animals belonging to three breeds (Aberdeen Angus, Limousine, and Blonde d’Aquitaine) were used (120 samples). After the acquisition of images by MSI and segmentation of their morphological parameters, a back propagation artificial neural network (ANN) model coupled with partial least squares was applied to predict the muscular parameters cited above. The results presented a high accuracy and are promising (R² test > 0.90) for practical applications. For example, considering the prediction of IMF, the regression model giving the best ANN model exhibited R²P = 0.99 and RMSEP = 0.103 g × 100 g⁻¹ DM.

Analysis of Scientific and Press Articles Related to Cultured Meat for a Better Understanding of Its Perception

Cultured meat is presented by its advocates as a good alternative for consumers who want to be more ethically minded but who do not wish to change their diet. This novel food has become an emerging topic in both the scientific field and the press media. From a bibliometric analysis of scientific publications and on a sociometric analysis of the mainstream press, the aim of this study was to identify potential differences between the scientific view and the public perception. This research analyzed the publications indexed by SCI-EXPANDED in the Web of Science Core Collection database owned by Clarivate Analytics, for scientific literature analysis, and indexed by the Factiva database, for the press media. A total of 327 scientific publications were analyzed according to year of publication and country and institution of origin, also including coauthorships, co-citations, and scientific fields' and journals' networks. A knowledge mapping using VOSviewer was used to study the literature in the field. Based on Factiva, 12,900 press articles dealing with artificial meat, mainly in English, have been found through public databases. The main conclusion is that cultured meat is mainly developing in the USA and the UK, with other countries, such as China, observing the trend for potential future applications. Scientific articles seemed initially to focus mainly on technical aspects of artificial meat and more recently on health value, consumer's acceptance, and sustainability. However, the potential environment-friendly effects of this novel food are more and more studied or described in scientific or press articles.

European conformation and fat scores of bovine carcasses are not good indicators of marbling

Marbling is one of the primary carcass attributes utilized in most beef grading systems for eating quality evaluation. In Europe, the current beef grading system is the EUROP grid, which is focused on carcass commercial value and production yield rather than eating quality estimation. The aim of this study was to investigate the relationship between marbling and the most common scores for carcass classification in Europe. If there are strong associations between marbling and European classification scores, marbling score may be estimated from the carcass characteristics. However, this study indicated that European classification scores explain only a slight proportion of the variance in marbling score (32%, 46%, 34% and 21% for the entire cattle group, young bulls, females and steers, respectively). Therefore, whereas the EUROP grid is well adapted to estimate yield, it does not reflect marbling at all. The European beef industry should take into account additional indicators related to beef palatability to assist the determination of the commercial value of carcasses.

Various Statistical Approaches to Assess and Predict Carcass and Meat Quality Traits

The beef industry is organized around different stakeholders, each with their own expectations, sometimes antagonistic. This article first outlines these differing perspectives. Then, various optimization models that might integrate all these expectations are described. The final goal is to define practices that could increase value for animal production, carcasses and meat whilst simultaneously meeting the main expectations of the beef industry. Different models previously developed worldwide are proposed here. Two new computational methodologies that allow the simultaneous selection of the best regression models and the most interesting covariates to predict carcass and/or meat quality are developed. Then, a method of variable clustering is explained that is accurate in evaluating the interrelationships between different parameters of interest. Finally, some principles for the management of quality trade-offs are presented and the Meat Standards Australia model is discussed. The "Pareto front" is an interesting approach to deal jointly with the different sets of expectations and to propose a method that could optimize all expectations together.

The Myth of Cultured Meat: A Review

To satisfy the increasing demand for food by the growing human population, cultured meat (also called in vitro, artificial or lab-grown meat) is presented by its advocates as a good alternative for consumers who want to be more responsible but do not wish to change their diet. This review aims to update the current knowledge on this subject by focusing on recent publications and issues not well described previously. The main conclusion is that no major advances were observed despite many new publications. Indeed, in terms of technical issues, research is still required to optimize cell culture methodology. It is also almost impossible to reproduce the diversity of meats derived from various species, breeds and cuts. Although these are not yet known, we speculated on the potential health benefits and drawbacks of cultured meat. Unlike conventional meat, cultured muscle cells may be safer, without any adjacent digestive organs. On the other hand, with this high level of cell multiplication, some dysregulation is likely as happens in cancer cells. Likewise, the control of its nutritional composition is still unclear, especially for micronutrients and iron. Regarding environmental issues, the potential advantages of cultured meat for greenhouse gas emissions are a matter of controversy, although less land will be used compared to livestock, ruminants in particular. However, more criteria need to be taken into account for a comparison with current meat production. Cultured meat will have to compete with other meat substitutes, especially plant-based alternatives. Consumer acceptance will be strongly influenced by many factors and consumers seem to dislike unnatural food. Ethically, cultured meat aims to use considerably fewer animals than conventional livestock farming. However, some animals will still have to be reared to harvest cells for the production of in vitro meat. Finally, we discussed in this review the nebulous status of cultured meat from a religious point of view. Indeed, religious authorities are still debating the question of whether in vitro meat is Kosher or Halal (e.g., compliant with Jewish or Islamic dietary laws).

Predicting the Quality of Meat: Myth or Reality?

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.

The associations between proteomic biomarkers and beef tenderness depend on the end-point cooking temperature, the country origin of the panelists and breed

Steaks of 74 animals from 3 young bull breeds (Aberdeen Angus, Limousin and Blond d'Aquitaine) were cooked at two end-point cooking temperatures (55 and 74 °C) and evaluated for tenderness by trained panelists from France (FR) and the United Kingdom (UK). Using principal component regressions, the tenderness scores of each breed, country origin of the panelists and cooking temperature were linked with the abundances of 21 protein biomarkers belonging to five biological pathways. Twelve regression equations were built and explained 68 to 95% of tenderness variability. A high dissimilarity in the retained biomarkers was observed among the equations and differences exist among breeds, cooking temperatures and country origin of the panelists. Among the 21 biomarkers, 6 proteins including structural (MyHC-I, MyHC-IIa, MyHC-IIx), oxidative stress (DJ-1, PRDX6) and proteolysis (CAPN1) were retained robustly in positive or negative directions in the tenderization process of Longissimus thoracis, regardless the breed, the end-point cooking temperature or the country origin of the panelist.

Current situation and future prospects for beef production in Europe - A review

The European Union (EU) is the world's third largest producer of beef. This contributes to the economy, rural development, social life, culture and gastronomy of Europe. The diversity of breeds, animal types (cows, bulls, steers, heifers) and farming systems (intensive, extensive on permanent or temporary pastures, mixed, breeders, feeders, etc) is a strength, and a weakness as the industry is often fragmented and poorly connected. There are also societal concerns regarding animal welfare and environmental issues, despite some positive environmental impacts of farming systems. The EU is amongst the most efficient for beef production as demonstrated by a relative low production of greenhouse gases. Due to regional differences in terms of climate, pasture availability, livestock practices and farms characteristics, productivity and incomes of beef producers vary widely across regions, being among the lowest of the agricultural systems. The beef industry is facing unprecedented challenges related to animal welfare, environmental impact, origin, authenticity, nutritional benefits and eating quality of beef. These may affect the whole industry, especially its farmers. It is therefore essential to bring the beef industry together to spread best practice and better exploit research to maintain and develop an economically viable and sustainable beef industry. Meeting consumers' expectations may be achieved by a better prediction of beef palatability using a modelling approach, such as in Australia. There is a need for accurate information and dissemination on the benefits and issues of beef for human health and for environmental impact. A better objective description of goods and services derived from livestock farming is also required. Putting into practice "agroecology" and organic farming principles are other potential avenues for the future. Different future scenarios can be written depending on the major driving forces, notably meat consumption, climate change, environmental policies and future organization of the supply chain.

Does growth path influence beef lipid deposition and fatty acid composition?

Despite the recent advances in transcriptomics, gene expression studies addressing cattle´s skeletal muscle adaptations in response to compensatory growth are warranted, particularly regarding lipid metabolism due to its impact in meat sensory and nutritional traits. In the present study, in comparison to ad libitum feeding, a period of feed restriction was used in order to understand the changes in bull´s lipid metabolism and gene expression of the adipogenic and lipogenic pathways after re-alimentation. Thus, 40 young Alentejana bulls were either fed ad libitum (CG group) from 9 to 18 months of age or subjected to food restriction from 9 to 15 months of age, and fed ad libitum until 24 months of age (DG group). The intramuscular fat (IMF) and total fatty acids (FA) contents were similar between groups. The major FA (>2%) contents were similar (16:0, 16:1c9, 18:1c9 and 18:2n-6) between treatments with the exception of 18:0 content that was 15% lower in DG than in CG and 20:4n-6 that tended to be greater on DG bulls. Regarding minor FA (<2%), the DG group presented greater proportions (P<0.01) of 17:1c9, 18:1t9, 18:1t10 (, 18:1c11), 18:1c13, 18:3n-6, 22:0, 22:4n-6 and 22:6n-3 and lower (P<0.05) proportions of 20:0, 18:1t16+c14, and branched chain FA (iso-15:0, anteiso-15:0, iso-16:0 and anteiso-17:0) than the CG group. Delta-9 desaturase activity indices were consistently greater (P<0.05) in DG, when compared to the CG group. Regarding microarray analysis, differentially expressed genes between CG and DG bulls were grouped in 5 main biological functions: lipid and nucleic acid metabolisms, small molecule biochemistry, molecular transport and translational modification. Discontinuous growth down-regulated the expression of ACACB (FC (fold-change) = 1.32), FABP3 (FC = 1.45), HADHA (FC = 1.41) and SLC37A4 (FC = 1.40) genes, when compared to the CG system (FDR<0.05). In contrast, in the CG bulls, the expression of ELOVL5 (FC = 1.58) and FASN (FC = 1.71) was down-regulated when compared to DG bulls. These results were confirmed to be significant (P<0.05) in the case of ELOVL5, FASN and SLC37A4, and almost significant for FABP3 by qRT-PCR analysis. The SCD1 and SCD5 gene expressions were not found to be affected by growth path. These results contribute to the still scarce knowledge about the mechanisms involved in fatty acid metabolism during compensatory growth which have decisive role on meat quality produced in Mediterranean areas.

Artificial meat and the future of the meat industry

The global population is estimated to plateau at 9 billion by the year 2050; however, projected food-production estimates would supply for only 8 billion people, using the ‘business as usual’ approach. In particular, the meat industry would need to increase production by ~50–73%. In response, there are several different options that have the potential to satisfy demand and increase production. Some of these options require advanced technologies and many may be considered as ‘artificial’ by different consumer groups. Within the meat industry itself, available technologies include selective breeding, agroecology systems, animal cloning and genetic modification. Alternatively, meat proteins can be replaced or substituted with proteins from plants, fungi, algae or insects. Finally, meat products could be produced using in vitro culturing and three-dimensional printing techniques. The protein produced by these techniques can be considered in the following three categories: modified livestock systems, synthetic meat systems, and meat substitutes. In the future, it is likely that meat substitutes will increase market share through competition with low-grade cuts of meat, sausages, ground meat and processed meat. However, synthetic meat systems and meat substitutes have significant barriers to commercialisation and widespread adoption that will affect their presence at least in the high-end premium sector in the market. To meet growing demands for protein, and in the face of growing competition from other sectors, the conventional meat industry must adopt new technologies and farming systems. These must be tailored to the challenges facing the industry and must effectively respond to consumer demands and the changing market place.

Inter-laboratory assessment by trained panelists from France and the United Kingdom of beef cooked at two different end-point temperatures

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.

Understanding Early Post-Mortem Biochemical Processes Underlying Meat Color and pH Decline in the Longissimus thoracis Muscle of Young Blond d'Aquitaine Bulls Using Protein Biomarkers

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.

Inverse relationships between biomarkers and beef tenderness according to contractile and metabolic properties of the muscle

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 index 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 good biomarker of low tenderness in the three breeds and in the two muscles. Proteins such as lactate dehydrogenase-B, myosin heavy chain IIx, and small heat shock proteins (Hsp27, Hsp20, and αB-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.

Fine mapping of quantitative trait loci underlying sensory meat quality traits in three French beef cattle breeds

Improving the traits that underlie meat quality is a major challenge in the beef industry. The objective of this paper was to detect QTL linked to sensory meat quality traits in 3 French beef cattle breeds. We genotyped 1,059, 1,219, and 947 young bulls and their sires belonging to the Charolais, Limousin, and Blonde d'Aquitaine breeds, respectively, using the Illumina BovineSNP50 BeadChip (Illumina Inc., San Diego, CA). After estimating relevant genetic parameters using VCE software, we performed a linkage disequilibrium and linkage analysis on 4 meat traits: intramuscular fat content, muscle lightness, shear force, and tenderness score. Heritability coefficients largely ranged between 0.10 and 0.24; however, they reached a maximum of 0.44 and 0.50 for intramuscular fat content and tenderness score, respectively, in the Charolais breed. The 2 meat texture traits, shear force and tenderness score, were strongly genetically correlated (-0.91 in the Charolais and Limousin breed and -0.86 in the Blonde d'Aquitaine breed), indicating that they are 2 different measures of approximately the same trait. The genetic correlation between tenderness and intramuscular fat content differed across breeds. Using a significance threshold of 5 × 10(-4) for QTL detection, we found more than 200 significant positions across the 29 autosomal chromosomes for the 4 traits in the Charolais and Blonde d'Aquitaine breeds; in contrast, there were only 78 significant positions in the Limousin breed. Few QTL were common across breeds. We detected QTL for intramuscular fat content located near the myostatin gene in the Charolais and Blonde d'Aquitaine breeds. No mutation in this gene has been reported for the Blonde d'Aquitaine breed; therefore, it suggests that an unknown mutation could be segregating in this breed. We confirmed that, in certain breeds, markers in the calpastatin and calpain 1 gene regions affect tenderness. We also found new QTL as several QTL on chromosome 3 that are significantly associated with meat tenderness in the Blonde d'Aquitaine breed. Overall, these results greatly contribute to the goal of building a panel of markers that can be used to select animals of high meat quality.

Chemical composition and structural characteristics of Arabian camel (Camelus dromedarius) m. longissimus thoracis

Saudi Arabian camels of four breeds (6 animals per breed) were used to evaluate characteristics and quality of their meat. Chemical composition, fibre cross sectional area, collagen content, muscle metabolism, cooking loss, pH at 24 h post mortem, colour values (except redness) and shear force of Longissimus thoracis (LT) muscle did not differ between the breeds. Elevated pH values and short sarcomeres reduced overall tenderisation, with a difference between myofibril fragmentation index (P<0.001) and sarcomere length (P<0.05) between breeds. A positive correlation was observed between the activities of the mitochondrial enzymes (r>0.49), between the glycolytic activities (PFK and LDH) (r=0.61) and between Myosin Heavy Chain IIa and LDH activity. The intramuscular fat content was positively associated with redness and muscle oxidative metabolism, whereas shear force had a slight positive association with collagen content and muscle glycolytic metabolism and a negative association with muscle oxidative metabolism and muscle fibre area.

Analytical limits of total and insoluble collagen content measurements and of type I and III collagen analysis by electrophoresis in bovine muscles

Three to 16 animals were necessary to detect a difference of 50-20% in total collagen contents in Longissimus thoracis muscle, between two experimental groups of cattle, using the facilities available in our laboratory. The inter-assay variability was higher for insoluble collagen content than for total collagen content. Consequently differences between two groups are determined less accurately for insoluble collagen content than for total collagen content. This may be partly compensated by repeated measurements (minimum 4) to detect a difference of 40% or even higher. The low reproducibility of type I and type III collagen contents determined by electrophoretic analysis is due to uncontrollable technical parameters. Normalisation of the results is thus necessary for accurate quantification. The recommended procedure is to use total protein content detected and quantified on the gels as a covariable in the statistical model. This procedure induces a 15% reduction in intra-subject variability, and hence in sample size required to detect significant differences.

Abundance of some skeletal muscle mitochondrial proteins is associated with increased blood serum insulin in bovine fetuses

The aim of this study was to investigate the evolution of the abundance of cytochrome oxidase c subunit IV (NCOIV) and beta subunit of ATP synthase (β-ATP) during the last third of gestation in bovine skeletal muscles. Semitendinosus, longissimus thoracis and rectus abdominis muscles were chosen for the immunoblotting of the respective protein levels. Muscle and blood samples from bovine fetuses of randomly selected breeds were collected at 180, 210, and 260 days post-conception (dpc). The muscle tissue expressions of NCOIV, β-ATP were compared to blood glucose and insulin. At 260 dpc, protein levels of NCOIV raised in skeletal muscles. Additionally, β-ATP in semitendinosus and longissimus thoracis were elevated and paralleled by higher concentrations of blood serum insulin. It corroborates our previous observations indicating that accelerated metabolic differentiation of bovine skeletal muscles is associated with elevated blood insulin and occurs during the last trimester of gestation. Our observations point to the connection between insulin-sensitivity and the molecular mechanisms of mitochondrial contribution to ontogenesis of skeletal muscles.

Specific fibre composition and metabolism of the rectus abdominis muscle of bovine Charolais cattle

BACKGROUND

An important variability of contractile and metabolic properties between muscles has been highlighted. In the literature, the majority of studies on beef sensorial quality concerns M. longissimus thoracis. M. rectus abdominis (RA) is easy to sample without huge carcass depreciation and may appear as an alternative to M. longissimus thoracis for fast and routine physicochemical analysis. It was considered interesting to assess the muscle fibres of M. rectus abdominis in comparison with M. longissimus thoracis (LT) and M. triceps brachii (TB) on the basis of metabolic and contractile properties, area and myosin heavy chain isoforms (MyHC) proportions. Immuno-histochemical, histochemical, histological and enzymological techniques were used. This research concerned two populations of Charolais cattle: RA was compared to TB in a population of 19 steers while RA was compared to LT in a population of 153 heifers.

RESULTS

RA muscle had higher mean fibre areas (3350 microm(2) vs 2142 to 2639 microm(2)) than the two other muscles. In RA muscle, the slow-oxidative fibres were the largest (3957 microm(2)) and the fast-glycolytic the smallest (2868 microm(2)). The reverse was observed in TB muscle (1725 and 2436 microm(2) respectively). In RA muscle, the distinction between fast-oxidative-glycolytic and fast-glycolytic fibres appeared difficult or impossible to establish, unlike in the other muscles. Consequently the classification based on ATPase and SDH activities seemed inappropriate, since the FOG fibres presented rather low SDH activity in this muscle in comparison to the other muscles of the carcass. RA muscle had a higher proportion of I fibres than TB and LT muscles, balanced by a lower proportion either of IIX fibres (in comparison to TB muscle) or of IIA fibres (in comparison to LT muscle). However, both oxidative and glycolytic enzyme activities were lower in RA than in TB muscle, although the LDH/ICDH ratio was higher in RA muscle (522 vs 340). Oxidative enzyme activities were higher in RA than in LT muscle, whereas glycolytic enzyme activity was lower. In RA muscle, contractile and metabolic properties appeared to be less well-correlated than in the two other muscles.

CONCLUSIONS

RA muscle has some particularities in comparison to the LT and TB muscles, especially concerning the unusual large cross-section surface of SO fibres and the very low oxidative activity of intermediate IIA fibres.