A systematic review of the definitions and interpretations in scientific literature of 'less but better' meat in high-income settings

Generation of three-dimensional meat-like tissue from stable pig epiblast stem cells

Cultured meat production has emerged as a breakthrough technology for the global food industry with the potential to reduce challenges associated with environmental sustainability, global public health, animal welfare, and competition for food between humans and animals. The muscle stem cell lines currently used for cultured meat cannot be passaged in vitro for extended periods of time. Here, we develop a directional differentiation system of porcine pre-gastrulation epiblast stem cells (pgEpiSCs) with stable cellular features and achieve serum-free myogenic differentiation of the pgEpiSCs. We show that the pgEpiSCs-derived skeletal muscle progenitor cells and skeletal muscle fibers have typical muscle cell characteristics and display skeletal muscle transcriptional features during myogenic differentiation. Importantly, we establish a three-dimensional differentiation system for shaping cultured tissue by screening plant-based edible scaffolds of non-animal origin, followed by the generation of pgEpiSCs-derived cultured meat. These advances provide a technical approach for the development of cultured meat.

Single-nucleus and bulk RNA sequencing reveal cellular and transcriptional mechanisms underlying lipid dynamics in high marbled pork

Pork is the most consumed meat in the world, and its quality is associated with human health. Intramuscular fat (IMF) deposition (also called marbling) is a key factor positively correlated with various quality traits and lipo-nutritional values of meat. However, the cell dynamics and transcriptional programs underlying lipid deposition in highly marbled meat are still unclear. Here, we used Laiwu pigs with high (HLW) or low (LLW) IMF contents to explore the cellular and transcriptional mechanisms underlying lipid deposition in highly-marbled pork by single-nucleus RNA sequencing (snRNA-seq) and bulk RNA sequencing. The HLW group had higher IMF contents but less drip loss than the LLW group. Lipidomics results revelled the changes of overall lipid classes composition (e.g., glycerolipids including triglycerides, diglycerides, and monoglycerides; sphingolipids including ceramides and monohexose ceramide significantly increased) between HLW and LLW groups. SnRNA-seq revealed nine distinct cell clusters, and the HLW group had a higher percentage of adipocytes (1.40% vs. 0.17%) than the LLW group. We identified 3 subpopulations of adipocytes, including PDE4D⁺/PDE7B⁺ (in HLW and LLW), DGAT2⁺/SCD⁺ (mostly in HLW) and FABP5⁺/SIAH1⁺ cells (mostly in HLW). Moreover, we showed that fibro/adipogenic progenitors could differentiate into IMF cells and contribute to 43.35% of adipocytes in mice. In addition, RNA-seq revealed different genes involved in lipid metabolism and fatty acid elongation. Our study provides new insights into the cellular and molecular signatures of marbling formation; such knowledge may facilitate the development of new strategies to increase IMF deposition and the lipo-nutritional quality of high marbled pork.

Conjugated linoleic acids inhibit lipid deposition in subcutaneous adipose tissue and alter lipid profiles in serum of pigs

Conjugated linoleic acids (CLAs) have served as a nutritional strategy to reduce fat deposition in adipose tissues of pigs. However, the effects of CLAs on lipid profiles in serum and how these lipid molecules regulate fat deposition are still unclear. In this study, we explored the effects of CLAs on regulating lipid deposition in adipose tissues in terms of lipid molecules and microbiota based on a Heigai pig model. A total of 56 Heigai finishing pigs (body weight: 85.58 ± 10.39 kg) were randomly divided into two treatments and fed diets containing 1% soyabean oil or 1% CLAs for 40 d. CLAs reduced fat deposition and affected fatty acids composition in adipose tissues of Heigai pigs via upregulating the expression of the lipolytic gene (hormone-sensitive lipase, HSL) in vivo and in vitro. CLAs also altered the biochemical immune indexes including reduced content of total cholesterol (TChol), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) and changed lipids profiles including decreased sphingolipids especially ceramides (Cers) and sphingomyelins (SMs) in serum of Heigai pigs. Mechanically, CLAs may decrease peroxisome proliferator-activated receptorγ (PPARγ) expression and further inhibit adipogenic differentiation in adipose tissues of pigs by suppressing the function of Cers in serum. Furthermore, Pearson's correlation analysis showed HSL expression was positively related to short-chain fatty acids (SCFAs) in the gut (P ≤ 0.05) but the abundance of Cers was negatively related to the production and functions of SCFAs (P ≤ 0.05). CLAs altered the distribution of the lipid in serum and inhibited adipogenic differentiation by suppressing the function of Cers and further decreasing PPARγ expression in adipose tissues of Heigai pigs. Besides, the HSL expression and the abundance of Cers are associated with the production and functions of SCFAs in the gut.

Pro-environmental food practices in EU countries strongly suggest mutually reinforcing improvements in gender equality and environmental sustainability

This paper seeks to understand how pro-environmental food practices among women and men in the EU can be supported by considering the interlinkages between gender equality and environmental sustainability. A special aspect is that the role of gender equality is interpreted in terms of Schwartz's theory on national cultural values, which relates gender equality to cultures that emphasize intellectual autonomy and egalitarianism. The paper investigated how pro-environmental food practices (including meat reduction) among women and men correlated with their countries' national income level and its level of gender equality. It was a multilevel analysis of survey data from 27 countries (Eurobarometer 95.1, Spring 2021). Considering that studies about gender equality and the environment often find problematically high correlations between gender equality and national income, this study focused on political gender equality (i.e. women's representation in parliament), which had desirable characteristics. National income and political gender equality had complementary impacts on the adoption of pro-environmental food practices (including meat reduction). Men reported more target practices when living in richer countries; the same applied even more strongly to women when living in richer and more politically gender-balanced countries. It was concluded that women may have developed more autonomy by, inter alia, adopting pro-environmental food practices. At the level of individual behavior, this illustrates "mutually reinforcing dynamics" in the pursuit of gender equality and environmental sustainability goals.

Ideological resistance to veg*n advocacy: An identity-based motivational account

Animal-based diets in Western countries are increasingly regarded as unsustainable because of their impact on human health, environmental and animal welfare. Promoting shifts toward more plant-based diets seems an effective way to avoid these harms in practice. Nevertheless, claims against the consumption of animal products contradict the ideology of the omnivorous majority known as carnism. Carnism supports animal-product consumption as a cherished social habit that is harmless and unavoidable and invalidates minorities with plant-based diets: vegetarians and vegans (veg*ns). In this theoretical review, we integrate socio-psychological and empirical literature to provide an identity-based motivational account of ideological resistance to veg*n advocacy. Advocates who argue against the consumption of animal products often make claims that it is harmful, and avoidable by making dietary changes toward veg*n diets. In response, omnivores are likely to experience a simultaneous threat to their moral identity and their identity as consumer of animal products, which may arouse motivations to rationalize animal-product consumption and to obscure harms. If omnivores engage in such motivated reasoning and motivated ignorance, this may also inform negative stereotyping and stigmatization of veg*n advocates. These "pro-carnist" and "counter-veg*n" defenses can be linked with various personal and social motivations to eat animal products (e.g., meat attachment, gender, speciesism) and reinforce commitment to and ambivalence about eating animal products. This does not mean, however, that veg*n advocates cannot exert any influence. An apparent resistance may mask indirect and private acceptance of advocates' claims, priming commitment to change behavior toward veg*n diets often at a later point in time. Based on our theoretical account, we provide directions for future research.