Standardization and validation of assay of selected omega-3 and omega-6 fatty acids from phospholipid fraction of red cell membrane using gas chromatography with flame ionization detector

Background Docosahexaenoic acid (DHA) is an important structural component of human brain and retina. Evidence exists linking nutritional status of pregnant mothers and cognitive functions of their born infants. The DHANI (Maternal DHA Supplementation and Offspring Neurodevelopment in India) trial was implemented to evaluate the effect of maternal supplementation with DHA during pregnancy and for 6 months following delivery on motor and mental development of infants at 1 and 12 months. We describe here the standardization and validation of an assay for measurement of selected omega-3 and omega-6 fatty acids from the phospholipid fraction of red blood cells to assess their status in mothers at baseline, delivery and 6 months post-delivery and for infants in cord blood and at 1 and 12 months of age. The validated method has been used for the analysis of samples for DHANI. Methods Lipids were extracted from a pool of red blood cells, separated using thin layer chromatography. The phospholipid fraction was esterified, and fatty acids were separated by gas chromatography using a flame ionization detector. Result The method accuracy for DHA was between 97 - 98% and between 91 - 95% for arachidonic acid (AA) at three different concentrations. The intra-assay and inter-assay coefficient of variation for the fatty acids ranged from 1.19 to 5.7% and 0.78 to 13.0% respectively. Intraclass correlation (ICC), as a measure of reproducibility, ranged between 0.689 and 0.996. A good linearity was observed for all the fatty acids between concentrations of 0.2–4 μg/ml. Conclusion The standardized and validated method is suitable for implementation in large epidemiological studies for evaluation of fatty acids and in nutritional trials for assessment of fatty acid content of various lipid classes.

Near-Infrared Reflectance Spectroscopy for Predicting the Phospholipid Fraction and the Total Fatty Acid Composition of Freeze-Dried Beef

Research on fatty acids (FA) is important because their intake is related to human health. NIRS can be a useful tool to estimate the FA of beef but due to the high moisture and the high absorbance of water makes it difficult to calibrate the analyses. This work evaluated near-infrared reflectance spectroscopy as a tool to assess the total fatty acid composition and the phospholipid fraction of fatty acids of beef using freeze-dried meat. An average of 22 unrelated pure breed young bulls from 15 European breeds were reared on a common concentrate-based diet. A total of 332 longissimus thoracis steaks were analysed for fatty acid composition and a freeze-dried sample was subjected to near-infrared spectral analysis. 220 samples (67%) were used as a calibration set with the remaining 110 (33%) being used for validation of the models obtained. There was a large variation in the total FA concentration across the animals giving a good data set for the analysis and whilst the coefficient of variation was nearly 68% for the monounsaturated FA it was only 27% for the polyunsaturated fatty acids (PUFA). PLS method was used to develop the prediction models. The models for the phospholipid fraction had a low R2p and high standard error, while models for neutral lipid had the best performance, in general. It was not possible to obtain a good prediction of many individual PUFA concentrations being present at low concentrations and less variable than other FA. The best models were developed for Total FA, saturated FA, 9c18:1 and 16:1 with R2p greater than 0.76. This study indicates that NIRS is a feasible and useful tool for screening purposes and it has the potential to predict most of the FA of freeze-dried beef.

Effects of taurine intake on serum lipids in young women

Background: Taurine is an abundant amino acid in human cells, promoting ocular and biliary health, which is also used to treat congestive heart failure, hypertension, and hepatitis. Recently, taurine-enriched energy drinks have become popular with young adults, but the effects of taurine on serum lipids in young adults are unknown.Objective: We studied the influence of oral administration of taurine on serum lipid levels in healthy young women.Methods: Ten healthy young women with a mean body mass index of 20.0kg/m2, apolipoprotein E (apoE) phenotype 3/3 and normal menstrual cycles participated. Each subject was instructed to orally ingest 1g of taurine powder after each meal (3g/day) in addition to their usual diets during one menstrual cycle. Before and at the end of taurine intake, physical measurements and blood collection were performed in the morning after a 12-h fast, and 3-day weighted dietary records were obtained. Concentrations of serum lipids, apolipoproteins, and fatty acids in the serum phospholipid fraction were measured.Results: The subjects showed good compliance with taurine intake and none reported adverse effects during the experimental period. After taurine intake, concentrations of total cholesterol, low density lipoprotein cholesterol (LDL-C), free cholesterol, and apolipoprotein B (apoB) increased (p<0.05), while phospholipids tended to increase (p=0.051). Fatty acids in the serum phospholipid fraction also significantly increased (p<0.05). However, triglyceride, remnant-like particle cholesterol, remnant-like particle triglyceride, apoE, the apolipoprotein A-1 (apoA- 1)/apoB ratio and the LDL-C/apoB ratio were unchanged. Furthermore, body weight was significantly increased (p<0.01), but did not correlate with changes either in serum lipids or nutrient intakes.Conclusion: These results suggest that high taurine intake affects lipoprotein metabolism and increases serum lipids in slightly lean young women.Key Words: Taurine, slightly lean young women, serum lipids, remnant lipoprotein, fatty acids of the serum phospholipid fraction.

The influence of gibberellin on the level of nucleic acids and other phosphate fractions in maize seedlings

Treatment of maize seedes with GA3 increased the content of water, the phosphate acid soluble fraction, the phospholipid fraction and the low molecular weight r-RNA, s-RNA, DNA-RNA fractions in 5-days-old seedlings. On the other hand, the contents of RNA and DNA in such seedlings decreased.