Selenium (Se) is an essential human micronutrient. Deficiency of Se decreases the activity of selenoproteins and can compromise immune and thyroid function and cognitive development, and increase risks from non-communicable diseases. The prevalence of Se deficiency is unknown in many countries, especially in sub-Saharan Africa (SSA). Here we report that the risk of Se deficiency in Malawi is large among a nationally representative population of 2,761 people. For example, 62.5% and 29.6% of women of reproductive age (WRA, n = 802) had plasma Se concentrations below the thresholds for the optimal activity of the selenoproteins glutathione peroxidase 3 (GPx3; <86.9 ng mL −1 ) and iodothyronine deiodinase (IDI; <64.8 ng mL −1 ), respectively. This is the first nationally representative evidence of widespread Se deficiency in SSA. Geostatistical modelling shows that Se deficiency risks are influenced by soil type, and also by proximity to Lake Malawi where more fish is likely to be consumed. Selenium deficiency should be quantified more widely in existing national micronutrient surveillance programmes in SSA given the marginal additional cost this would incur.

Sustainable production of healthy food for a growing global population, in the face of the uncertainties of climate change, represents a major challenge for the coming decade. Livestock provide food with high nutritional value but are frequently fed on human-edible crops and are associated with significant production of greenhouse gases. Recent years have seen increasing interest in the farming of insects as a sustainable source of human food, or as a replacement of ingredients such as soya or fishmeal in the feeds of terrestrial livestock or fish. This review provides an overview of insect physiology and growth regulation, considers the requirements for insect farming and mass production, and summarizes the nutritional value of the 10 most commonly studied insect species, before reviewing the literature on the use of insects as feed and food. We highlight the challenges required to develop a sustainable, safe, and affordable insect farming industry. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 9 is February 16, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Butter, which is naturally enriched in cis-9, trans-11 conjugated linoleic acid (rumenic acid; RA) and vaccenic acid (VA), has been shown to be an effective anticarcinogen in studies with animal models; however, there has been no examination of the effects of a naturally derived source of VA and RA on atherosclerosis-related biomarkers. The current study was designed to determine the effect of a diet containing VA/RA-enriched butter on plasma lipoproteins and tissue fatty acid profiles in cholesterol-fed hamsters. Male Golden Syrian hamsters were fed diets containing 0.2% cholesterol and 20% added fat as: 1) Control, 20% standard butter (CT); 2) 5% standard butter + 15% VA/RA-enriched butter (EB); 3) 15% standard butter + 5% partially-hydrogenated vegetable oil (VO). After 4 wk, plasma lipoproteins were isolated, cholesterol quantified, and tissue fatty acid profiles determined. Tissue concentrations of VA and RA were increased by consumption of the EB diet compared with both the CT and VO diets, whereas the VO diet increased their concentration compared with the CT diet only. Total and LDL cholesterol concentrations were significantly reduced in hamsters fed EB and VO compared with CT, whereas VLDL cholesterol concentrations were reduced in hamsters fed EB compared with those fed CT and VO. HDL cholesterol concentrations did not differ among treatments. The ratio of potentially atherogenic lipoproteins [VLDL + intermediate density lipoproteins (IDL) + LDL] to antiatherogenic HDL was significantly lower in hamsters fed VA/RA-enriched butter (0.60) than in those fed either control diet (1.70) or the diet containing partially hydrogenated vegetable oil (1.04). Thus, increasing the VA/RA concentration of butter results in a plasma lipoprotein cholesterol profile that is associated with a reduced risk of atherosclerosis.

Feeding sheep concentrate-based diets increases the oleic acid content of their tissues, whereas the cis-9, trans-11 conjugated linoleic acid (CLA) content is increased by feeding forage diets. Both these metabolic transformations could be attributable to increased activity of stearoyl-CoA desaturase (SCD). Therefore, the effect of forage or concentrate feeding regimens on the fatty acid composition of sheep tissues were investigated to determine whether any changes are related to an alteration of SCD mRNA levels. Twenty-four ewe lambs were randomly allotted to one of three dietary treatment groups: 1) dehydrated grass pellets, 2) concentrate diet fed to achieve a growth rate similar to that of the dehydrated grass pellets, and 3) the same concentrate diet approaching ad libitum intake. As expected, animals fed ad libitum concentrates grew at a greater (P = 0.001) rate (280 g/d) than those fed either of the other two diets (180 g/d), which were similar. In samples of liver and the three adipose tissue depots studied, the concentration of oleic acid from sheep fed either level of the concentrate diet was greater (P < 0.001) than from animals fed forage. This was associated with an increase (P < 0.05) in the ratio of SCD to acetyl-CoA carboxylase mRNA in adipose tissue and liver. Compared with concentrate-fed, the forage-fed lambs had increased (P < 0.05) levels of the cis-9, trans-11 isomer of CLA and C18:1, trans-11 in all their tissues, although the levels of SCD mRNA were lower. It therefore seems that the increased oleic acid content of sheep tissues in response to concentrate-rich diets is associated with an increase in SCD gene expression. By contrast, the increased concentration of CLA in animals fed forage-based diets is associated with an increase in substrate (C18:1 trans-11) availability.