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Triacylglycerol Concentrations (triacylglycerol + concentration)
Selected AbstractsStructural and compositional changes in very low density lipoprotein triacylglycerols during basal lipolysisFEBS JOURNAL, Issue 24 2002Jyrki J. Ågren Triacylglycerols secreted by liver and carried by very low density lipoprotein (VLDL) are hydrolysed in circulation by lipoprotein and hepatic lipases. These enzymes have been shown to have positional and fatty acid specificity in vitro. If there were specificity in basal lipolysis in vivo, triacylglycerol compositions of circulating and newly secreted VLDL would be different. To study this we compared the composition of normal fasting VLDL triacylglycerol of Wistar rats to that obtained after blocking lipolysis by Triton WR1339, which increased plasma VLDL triacylglycerol concentration about 4.7-fold in 2 h. Analyses of molecular species of sn -1,2- and sn -2,3-diacylglycerol moieties and stereospecific triacylglycerol analysis revealed major differences between the groups in the VLDL triacylglycerol composition. In nontreated rats, the proportion of 16:0 was higher and that of 18:2n-6 lower in the sn -1 position. The proportion of 14:0 was lower in all positions and that of 18:0 was lower in the sn -1 and sn -3 positions in nontreated rats whereas the proportions of 20:4n-6, 20:5n-3, 22:5n-3 and 22:6n-3 were higher in the sn -1 and lower in the sn -2 position. These results suggest that the fatty acid of the sn -1 position is the most decisive factor in determining the sensitivity for hydrolysis of the triacylglycerol. In addition, triacylglycerol species with highly unsaturated fatty acids in the sn -2 position also favoured hydrolysis. The in vivo substrate specificity followed only partly that obtained in in vitro studies indicating that the nature of molecular association of fatty acids in natural triacylglycerol affects its susceptibility to lipolysis. To conclude, our results indicate that preferential basal lipolysis leads to major structural differences between circulating and newly secreted VLDL triacylglycerol. These differences extend beyond those anticipated from analysis of total fatty acids and constitute a previously unrecognized feature of VLDL triacylglycerol metabolism. [source] Production and clearance of plasma triacylglycerols in ponies fed diets containing either medium-chain triacylglycerols or soya bean oilJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5-6 2003J. M. Hallebeek Summary The hypothesis was tested that feeding ponies a diet containing medium-chain triacylglcyerols (MCT) instead of soya bean oil causes an increase in the production of plasma triacylglycerols, which, under steady-state conditions, is associated with an increased clearance of triacylglycerols. Six ponies were fed rations containing either MCT or an isoenergetic amount of soya bean oil according to a cross-over design. The concentration of MCT in the total dietary dry matter was about 13%. When the ponies were fed the diets for 3 weeks, plasma triacylglycerol concentrations were 0.42 ± 0.09 and 0.17 ± 0.03 mmol/l (mean ± SE, n = 6; p < 0.05) for the MCT and soya bean-oil treatment, respectively. Plasma triacylglycerol production was assessed using the Triton method and clearance with the use of Intralipid® infusion. Plasma triacylglycerol production was 2.91 ± 0.88 and 0.50 ± 0.14 ,mol/l·min (means ± SE, n = 4; p < 0.05) for the diets containing MCT and soya bean oil, respectively. It is suggested that the calculated rates of triacylglycerol production are underestimated, the deviation being greatest when the ponies were fed the ration of soya bean oil. Triacylglycerol clearance rates were calculated on the basis of group mean values for both the fractional clearance rate and the baseline levels of plasma triacylglycerols; the values were 4.28 and 3.52 ,mol/l·min for MCT and soya bean oil feeding, respectively. The mean, absolute clearance rates as based on those found in individual ponies did not show an increase when the diet with MCT was fed. Nevertheless, it is concluded that the data obtained support our hypothesis. [source] Changing from a mixed to self-selected vegetarian diet , influence on blood lipidsJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 5 2002F. Robinson Abstract Objective To observe any changes in serum concentrations of lipids, when UK meat-eaters switch to a self selected vegetarian diet for 6 months. Design Observational study using capillary blood samples and 3-day estimated dietary diary. Setting Free-living subjects in the North-West of England. Subjects Twelve male and 31 female adult volunteers aged between 18 and 42 years. Outcome measures Serum lipids; nutrient intake and anthropometric measurements at baseline and 6 months after switching to a self-selected vegetarian diet. Results Total energy intake and amount of energy derived from saturated fatty acids decreased significantly after changing to a vegetarian diet (P < 0.05) whereas energy derived from carbohydrate, and intakes of nonstarch polysaccharide intake increased. On switching to a vegetarian diet, total cholesterol and triacylglycerol concentrations were not significantly changed, but HDL-C was 21% higher than at baseline (1.21 mmol L,1 vs. 1.47 mmol L,1; P = 0.001). Conclusions These results suggest that beneficial changes to diet occurred on changing to a self-selected vegetarian diet. Changing to a self-selected vegetarian diet appears to be one way of achieving a better blood lipid profile. [source] Fat Feeding Increases Equine Heparin-Released Lipoprotein Lipase ActivityJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2001Suzanne N.J. Geelen The aim of this study was to establish the dose-response relationship between fat intake and heparin-released plasma lipoprotein lipase (LPL) activity in horses. Eight mature trotters were fed 4 rations with different fat levels (3.0, 5.0, 7.7, or 10.8% fat in the dry matter) according to a 4 × 4 Latin square design. The experimental rations consisted of hay and different concentrates; the concentrates and hay were given in a 3 :1 ratio on an energy basis. Soybean oil was added to the concentrates at the expense of isoenergetic amounts of glucose. Blood samples were taken at the end of each dietary period, which lasted 3 weeks. Fat feeding was found to increase heparin-released plasma LPL activity in a dose-dependent fashion. When the data from this study and previous studies were combined it was calculated that an increase in fat intake by 1 g/kg dry matter is associated with an increase in LPL activity by 0.98 ,mol fatty acid released.mL -1.h -1. Fat feeding raised the plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, and phospholipids. Diet did not have a statistically significant effect on plasma triacylglycerol concentrations. The results are discussed in the light of the possible enhancing effect of fat feeding on the oxidative capacity of skeletal muscle. [source] Carbohydrate utilization by juvenile silver perch, Bidyanus bidyanus (Mitchell).AQUACULTURE RESEARCH, Issue 2 2003Abstract The ability of silver perch (Bidyanus bidyanus) to digest and utilize dietary starch or starch breakdown products was investigated. For experiment 1 the ability of silver perch (2.7 ± 0.01 g) to digest wheat starch at two dietary inclusion levels (30% or 60%), each at four levels of gelatinization (0%, 25%, 50% or 80%), was investigated over a 31-day period. For experiment 2, the ability of silver perch (15.9± 0.25 g) to digest wheat starch, dextrin (at three levels of dextrinization), maltose, glucose and pea starch, all at the 30% inclusion level, was investigated over a 41-day period. Water temperature for both experiments was 25 ± 1 °C. Apparent digestibility coefficients (ADCs) for starch, dry matter (DM) and energy were affected by both degree of gelatinization (80% > 50% > 25% = 0%) and inclusion level (30% > 60%). Specific growth rate (SGR) was unaffected by the inclusion of 30% starch; however, it was reduced at the 60% starch content level. Degree of gelatinization had no effect on SGR. For experiment 2, there were significant differences between carbohydrate and DM ADCs for the test ingredients. The carbohydrate, DM and energy ADCs were ranked as follows: dextrin (Fieldose 9) = dextrin (Fieldose 17) = dextrin (Fieldose 30) = gelatinized wheat starch = maltose = glucose > raw wheat starch > raw pea starch. The protein ADC of the diets, postprandial plasma glucose concentration and SGR were all unaffected by ingredient type. For both experiments, HSI tended to increase with carbohydrate inclusion. Liver glycogen concentrations were also elevated, but muscle glycogen and liver and muscle triacylglycerol concentrations were unaffected. Digestibility of starch by silver perch is clearly affected by inclusion content and processing. [source] | ||||||||||