Does Consumption of Baker's Yeast (Saccharomyces cerevisiae) by Black Soldier Fly (Diptera: Stratiomyidae) Larvae Affect Their Fatty Acid Composition?

Fatty acids are important compounds for insects, but the requirements for essential fatty acids may differ between insect species. Most of the fatty acids are acquired through the insect's diet; therefore, supplementing the diet with baker's yeast (Saccharomyces cerevisiae Meyen ex E.C. Hansen), which produces unsaturated fatty acids, was predicted to affect the fatty acid composition of the insect. The tested insect was the black soldier fly (BSF) (Hermetia illucens L.), that is used as a source of protein and fat in feed. Therefore, there is importance for BSF larvae (BSFL) nutritional composition, especially the unsaturated fatty acids content, which is one of the nutritional limitations for mammalian diets. The dominant fatty acids of the tested BSFL were the saturated fatty acids: lauric, myristic, and palmitic acids, as found in other BSF studies. Oleic acid (c18:1) and linoleic acid (C18:2) were the abundant unsaturated fatty acids in the BSFL. The proportion of linoleic acid was higher in the substrate with the supplemental yeast; however, this did not affect its proportion in the larvae. The higher proportion of linoleic acid may have been exploited as a source for production of saturated lauric acid. Therefore, providing unsaturated fatty acids to the substrate through supplemental baker's yeast is not the most efficient way to increase the proportion of unsaturated fatty acids in the larvae.

Sepiolite Clay Attenuates the Development of Hypercholesterolemia and Obesity in Mice Fed a High-Fat High-Cholesterol Diet.

Obesity reduces the quality of life and life expectancy, whereas nonoperative interventions have shown poor results so far. Statins effectively combat hypercholesterolemia but are not well tolerated at high doses, raising the need for coprescription with cholesterol sorbents and/or absorption inhibitors. Montmorillonite (MMT) clay was found to attenuate hypercholesterolemia and obesity by reducing cholesterol and fat absorption. However, acicular clay-like sepiolite may offer better results due to its more substantial adsorption of nonpolar molecules. We herein aimed at (1) assessing in vitro the capacity of sepiolite to adsorb edible oil and cholesterol compared with that of MMT and (2) assessing in vivo the effect of continuous feeding on a high-fat high-cholesterol diet (HFD) (53.6% w/w fat and 0.2% cholesterol) supplemented with 5% (w/w) edible sepiolite, on diet-induced obesity rate, hypercholesterolemia, and hyperlipidemia. Fourier transform infrared spectroscopy showed in vitro that sepiolite adsorption of olive oil and cholesterol was five to eight times greater than that of MMT clay. Sepiolite supplementation to HFD fed to mature mice for 12.5 weeks resulted in lower total blood cholesterol and triacylglycerol levels and attenuated body weight gain, by reducing fat gain. Sepiolite supplementation did not affect energy intake but increased fecal extraction of sterols and lipids, without notable side effects. These results demonstrate that supplementing a HFD with sepiolite attenuates gastrointestinal absorption of dietary lipids and sterols, thus mitigating obesity, hyperlipidemia, and hypercholesterolemia. Further exploration of the efficacy, mechanism of action, and safety of sepiolite as a food supplement for combating the metabolic syndrome is needed.