There is increasing evidence to indicate that nutrition is an important factor involved in the onset and development of several chronic human diseases including cancer, cardiovascular disease (CVD), type II diabetes and obesity. Clinical studies implicate excessive consumption of medium-chain saturated fatty acids (SFA) and trans-fatty acids (TFA) as risk factors for CVD, and in the aetiology of other chronic conditions. Ruminant-derived foods are significant sources of medium-chain SFA and TFA in the human diet, but also provide high-quality protein, essential micronutrients and several bioactive lipids. Altering the fatty acid composition of ruminant-derived foods offers the opportunity to align the consumption of fatty acids in human populations with public health policies without the need for substantial changes in eating habits. Replacing conserved forages with fresh grass or dietary plant oil and oilseed supplements can be used to lower medium-chain and total SFA content and increase cis-9 18:1, total conjugated linoleic acid (CLA), n-3 and n-6 polyunsaturated fatty acids (PUFA) to a variable extent in ruminant milk. However, inclusion of fish oil or marine algae in the ruminant diet results in marginal enrichment of 20-or 22-carbon PUFA in milk. Studies in growing ruminants have confirmed that the same nutritional strategies improve the balance of n-6/n-3 PUFA, and increase CLA and longchain n-3 PUFA in ruminant meat, but the potential to lower medium-chain and total SFA is limited. Attempts to alter meat and milk fatty acid composition through changes in the diet fed to ruminants are often accompanied by several-fold increases in TFA concentrations. In extreme cases, the distribution of trans 18:1 and 18:2 isomers in ruminant foods may resemble that of partially hydrogenated plant oils. Changes in milk fat or muscle lipid composition in response to diet are now known to be accompanied by tissue-specific alterations in the expression of one or more lipogenic genes. Breed influences both milk and muscle fat content, although recent studies have confirmed the occurrence of genetic variability in transcript abundance and activity of enzymes involved in lipid synthesis and identified polymorphisms for several key lipogenic genes in lactating and growing cattle. Although nutrition is the major factor influencing the fatty acid composition of ruminant-derived foods, further progress can be expected through the use of genomic or marker-assisted selection to increase the frequency of favourable genotypes and the formulation of diets to exploit this genetic potential.

Skeletal muscle consists of several tissues, such as muscle fibers and connective and adipose tissues. This review aims to describe the features of these various muscle components and their relationships with the technological, nutritional, and sensory properties of meat/flesh from different livestock and fish species. Thus, the contractile and metabolic types, size and number of muscle fibers, the content, composition and distribution of the connective tissue, and the content and lipid composition of intramuscular fat play a role in the determination of meat/flesh appearance, color, tenderness, juiciness, flavor, and technological value. Interestingly, the biochemical and structural characteristics of muscle fibers, intramuscular connective tissue, and intramuscular fat appear to play independent role, which suggests that the properties of these various muscle components can be independently modulated by genetics or environmental factors to achieve production efficiency and improve meat/flesh quality.

Identifying new targeted therapies that kill tumor cells while sparing normal tissue is a major challenge of cancer research. Using a high-throughput chemical synthetic lethal screen, we sought to identify compounds that exploit the loss of the von Hippel–Lindau (VHL) tumor suppressor gene, which occurs in about 80% of renal cell carcinomas (RCCs). RCCs, like many other cancers, are dependent on aerobic glycolysis for ATP production, a phenomenon known as the Warburg effect. The dependence of RCCs on glycolysis is in part a result of induction of glucose transporter 1 (GLUT1). Here, we report the identification of a class of compounds, the 3-series, exemplified by STF-31, which selectively kills RCCs by specifically targeting glucose uptake through GLUT1 and exploiting the unique dependence of these cells on GLUT1 for survival. Treatment with these agents inhibits the growth of RCCs by binding GLUT1 directly and impeding glucose uptake in vivo without toxicity to normal tissue. Activity of STF-31 in these experimental renal tumors can be monitored by [18F]fluorodeoxyglucose uptake by micro–positron emission tomography imaging, and therefore, these agents may be readily tested clinically in human tumors. Our results show that the Warburg effect confers distinct characteristics on tumor cells that can be selectively targeted for therapy.

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Changes in the amount and metabolism of adipose tissue (AT) occur in underfed ruminants, and are amplified during lactation, or in fat animals. The fat depot of the tail of some ovine breeds seems to play a particular role in adaptation to undernutrition; this role could be linked to its smaller adipocytes and high sensitivity to the lipolytic effect of catecholamines. Glucocorticoids and growth hormone probably interact to induce teleophoretic changes in the AT responses to adenosine and catecholamines during lactation. Fat mobilization in dry ewes is related both to body fatness and to energy balance. The in vivo β-adrenergic lipolytic potential is primarily related to energy balance, whereas basal postprandial plasma non-esterified fatty acids (NEFA) are related to body fatness, and preprandial plasma NEFA is the best predictor of the actual body lipid loss. Several mechanisms seem to be aimed at avoiding excessive fat mobilization and/or insuring a return to the body fatness homeostatic set point. As well as providing the underfed animal with fatty acids as oxidative fuels, AT acts as an endocrine gland. The yield of leptin by ruminant AT is positively related to body fatness, decreased by underfeeding, β-adrenergic stimulation and short day length, and increased by insulin and glucocorticoids. This finding suggests that the leptin chronic (or acute) decrease in lean (or underfed respectively) ruminants is, as in rodents, a signal for endocrine, metabolic and behavioural adaptations aimed at restoring homeostasis.

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Lipid in the diet is known to enhance milk fat secretion and alter milk fatty acid composition in lactating goats. In the current experiment, the contribution of peripheral tissue and mammary gland lipid metabolism to changes in milk fat composition from plant oils was examined. Fourteen Alpine goats in midlactation were used in a 3 x 3 Latin square design with 28-d experimental periods. Treatments comprised maize silage-based diets containing no additional oil (M), sunflower-seed oil (MSO; 6.1% of diet DM), or linseed oil (MLO; 6.2% of diet DM). Compared with the control, milk yield was greater in goats fed MSO (3.37 and 3.62 kg/d, respectively), whereas MLO enhanced milk fat content (+3.9 g/kg), resulting in a 14% increase in milk fat secretion. Both MSO and MLO increased milk lactose secretion by 12 and 8%, respectively, compared with M. Relative to the control, plant oils decreased C10 to C16 secretion (32 and 24%, respectively, for MSO and MLO) and enhanced C18 output in milk (ca. 110%). Diets MSO and MLO increased cis-9 18:1 secretion in milk by 25 and 31%, respectively, compared with M. The outputs of trans-11 18:1 and cis-9, trans-11 18:2 in milk were increased 8.34- and 6.02-fold for MSO and 5.58- and 3.71-fold for MLO compared with M, and MSO increased trans-10 18:1 and trans-10, cis-12 18:2 secretion. Plant oils decreased milk fat cis-9 14:1/14:0; cis-9 16:1/16:0; cis-9 18:1/18:0; and cis-9, trans-11 18:2/trans-11 18:1 concentration ratios but had no effect on mammary stearoyl-CoA desaturase mRNA or activity. Furthermore, changes in milk fatty acid secretion were not associated with alterations in mammary acetyl-CoA carboxylase mRNA and activity, abundance of mRNA encoding for lipoprotein lipase and fatty acid synthase, or malic enzyme and glycerol-3-phosphate dehydrogenase activity in mammary tissue. Mammary lipoprotein lipase activity was increased with MSO relative to MLO. Treatments had no effect on glucose-6-phosphate dehydrogenase, malic enzyme, glycerol-3-phosphate dehydrogenase activity, or mRNA abundance and/or activity of lipoprotein lipase, acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase in liver or adipose tissue. In conclusion, inclusion of sunflower-seed oil and linseed oil in maize silage-based diets alters milk fatty acid secretion in goats via mechanisms independent of changes in mammary, hepatic, or adipose tissue lipogenic gene expression. Furthermore, data provided indications that the regulation of mammary lipogenic responses to plant oils on starch-rich diets differs between the caprine and bovine.