Browsing by Subject "Lipid extraction"
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Item Effects of a time-restricted high- or low-fat diet on lipid absorption(2021-12-07) Balderrama, Jesse, Jr.; Bray, Molly S.Background: Chronic high-fat diets and time-restricted feeding have been shown to impact multiple cardiometabolic parameters. The purpose of this work was to investigate the effects of timed macronutrient intake on lipid absorption. Methods: Adult male FVB/N mice were randomly assigned to one of 6 feeding groups (n=45, 7-8 animals/group) and kept on a strict 12h light: 12h dark feeding schedule (lights on at 10pm (Zeitgeber Time - ZT0) and lights off at 10am (ZT12)). Food was made available continuously to mice in the control ad libitum low-fat (CALF) and control ad libitum high-fat (CAHF) feeding groups. Mice in the control low-fat (CLF) and control high-fat (CHF) groups received low fat or high fat food, respectively, exclusively during ZT 12-16 and ZT 20-24. Mice in the early high-fat (EHF) group received access to high-fat food during ZT 12-16 and low-fat food during ZT 20-24. Mice in the early low-fat (ELF) group received access to the low-fat food during ZT 12-16, and high-fat food during ZT 20-24. EHF and ELF groups did not have access to food during ZT 16-20. Rodent diet foods were 45% kcal from fat or 10% kcal from fat in high-fat groups and low-fat groups, respectively. After 12 weeks of study protocol, fecal samples were collected over a 24h period. Lipid extractions were performed to quantify fecal lipid content. Plasma samples were collected during mice sacrifice and triglyceride concentration was quantified. Results: There was a significant effect of feeding group (p=0.0016) as well as a significant effect of time on fecal lipid content (p=<0.05). Cosinor analysis revealed that feeding groups CALF, CLF, EHF, ELF showed significant rhythmicity for fecal lipid content, with no rhythmicity in fecal lipid content for either group exclusively eating a high fat diet (CAHF and CHF). There was a significant difference in plasma triglycerides between feeding groups (F (5,24) = 13.14, p = <0.05). A Scheffe post hoc test revealed that fasting plasma triglycerides showed a trend toward higher concentrations in groups fed low-fat food. Conclusion: Chronic high-fat diets resulted in greater fecal lipid content and lower fasting plasma triglycerides compared to low-fat dietsItem Extraction of Algal LIpids and their Analysis by HPLC and Mass Spectrometry(Springer Verlag, 2012-08) Jones, J.; Manning, S.; Montoya, M.; Keller, K.; Poenie, M.Algae are a promising source of biofuel but claims about their lipid content can be ambiguous because extraction methods vary and lipid quantitation often does not distinguish between particular lipid classes. Here we compared methods for the extraction of algal lipids and showed that 2-ethoxyethanol (2-EE) provides superior lipid recovery (>150–200 %) compared to other common extraction solvents such as chloroform:methanol or hexane. Extractions of wet and dry algal biomass showed that 2-EE was more effective at extracting lipids from wet rather than dried algal pellets. To analyze lipid content we used normal-phase HPLC with parallel quantitation by an evaporative light scattering detector and a mass spectrometer. Analysis of crude lipid extracts showed that all major lipid classes could be identified and quantified and revealed a surprisingly large amount of saturated hydrocarbons (HC). This HC fraction was isolated from extracts of bioreactor-grown algae and further analyzed by HPLC/MS, NMR, and GC/MS. The results showed that the sample consisted of a mixture of saturated, straight- and branched-chain HC of different chain lengths. These algal HC could represent an alternative biofuel to triacylglycerols (TAG) that could feed directly into the current petroleum infrastructure.