Male-specific amelioration of lipid metabolism by edible insect Locusta migratoria in rats fed a cholesterol diet: Ingredients, mechanisms, and sex-differences

Edible insects are expected to become alternative and sustainable food resources that will help ensure food security. Among them, the migratory locust (ML), which contains n-3 fatty acids (FA) that bind multiple lipid species, phytosterols, chitin, and resistant proteins, could ameliorate dyslipidemia by improving lipoprotein metabolism. However, since the positive effects of female hormones on lipid metabolism are well-known, the effects of ML supplementation on lipid metabolism may differ between sexes. This study investigated the ability of the ML supplementation to improve lipid metabolism in male and premenopausal female rats fed a 0.5% cholesterol diet for 4 weeks. Notably only in male rats, ML supplementation exhibited reduced plasma lipid levels in all major lipoprotein fractions, particularly the very small low-density lipoprotein fractions, which are more closely related to dyslipidemia. In the liver of male rats, ML supplementation suppressed enzymatic activities and mRNA expressions related to FA synthesis, FA desaturation, very low-density lipoprotein formation, and cholesterol synthesis, as well as dietary lipid absorption. Additionally in the cecum of male rats, ML supplementation increased certain alpha diversity indices and the abundance of the <i>Akkermansia</i> genus, which can improve lipid metabolism. Furthermore, ML supplementation increased anti-inflammatory n-3 FA levels, whereas suppressed inflammation-induced n-6 FA levels in the plasma and liver, and increased fecal lipid content in rats regardless of sex. Overall, ML supplementation was found to have an improvement effect on lipid metabolism, particularly in male rats, by suppressing lipid absorption and hepatic lipogenesis, as well as altering the cecal microbiota.