Induction in Gallus domesticus of experimental hypercholesterolemia by saturated fat. Effects on cholesterogenic enzyme activity

Is Almond Consumption More Effective Than Reduced Dietary Saturated Fat at Decreasing Plasma Total Cholesterol and LDL-c Levels? A Theoretical Approach

Hypercholesterolemia can be a consequence of excessive dietary saturated fatty acid (SFA), while almond-supplemented diets can improve lipid profiles. However, the differential and independent impacts of dietary SFA and almondsupplemented diets on plasma total cholesterol (pTC) and low-density lipoprotein (pLDL-c) concentrations have not been directly compared and are not well described. We reviewed the available data to construct multiple regression analyses to theoretically assess the impact of relative almond intake (RAI) and dietary SFA on reducing pTC and pLDL-c concentrations. Strong, negative correlations between RAI and percent change in mean pTC (R = 0.776; P = 0.005) and RAI and percent change in mean pLDL-c (R = 0.818; P = 0.002) were detected. The relationships between percent change in mean dietary SFA, and percent change in mean pTC and mean pLDL-c were weaker and only significant for pLDL-c. The multiple regression analyses demonstrated modest improvements in the strength of the correlations for both pTC (R = 0.804; P = 0.016) and pLDL-c (R = 0.855; P = 0.005). The models suggest that the increase in RAI contributes to the reduction in pTC and pLDL-c to a greater extent than a reduction in dietary SFA, but a simultaneous decrease in dietary SFA should further improve lipid profiles.

Dietary fish oil reduces cholesterol and arachidonic acid levels in chick plasma and very low density lipoprotein

The mechanisms involved in the hypolipidemic effects of fish oil have not been clearly established. This study shows that supplementation of 10% menhaden oil to the chick diet for 7 days produced a significant hypocholesterolemia and hypotriglyceridemia. Fatty acid composition of chick plasma drastically changed by the same dietary manipulation. Percentages of 20:5 and 22:6 n-3 fatty acids strongly increased, while percentages of 20:4 n-6, 18:2 n-6, and 18:1 n-9 significantly decreased. Changes observed in the relative percentages were parallel to those obtained in the amount of each fatty acid. Ratio of n-3/n-6 clearly decreased in plasma by fish oil feeding. Total cholesterol and triacylglycerol contents decreased in high density lipoprotein (HDL) but did not change in low density lipoprotein (LDL). All chemical constituents of very low density lipoprotein (VLDL) significantly decreased after the first week of menhaden oil supplementation to the diet. Similar modifications in fatty acid composition of the three lipoprotein fractions were also found. Our results suggest that the hypocholesterolemic effects of fish oil may be mediated by the depletion in VLDL synthesis and secretion into the chick plasma. On the other hand, the strong decrease found in the arachidonic acid (AA) content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.

Synergism between the effects of dietary cholesterol and coconut oil on plasma, liver and lipoprotein composition of neonatal chick

The nature of the synergism between dietary factors and the development of atherosclerosis has not been fully defined. Our studies showed that simultaneous supplementation of 10% saturated fat rich in 12:0 and 14:0 fatty acids (coconut oil) plus 1% cholesterol to the diet produced a sharp increase of plasma cholesterol, indicating a synergic influence of both dietary constituents. This increase was especially patent in the VLDL fraction, modifying the distribution of other lipid components between the core and the surface of these particles. These changes are consistent with the atherogenic function of VLDL and its responsiveness to dietary manipulation.

Supplementation of coconut oil from different sources to the diet induces cellular damage and rapid changes in fatty acid composition of chick liver and hepatic mitochondria

Supplementation of 20% coconut oil from two commercial sources pharmaceutical ("Pharmacy") and cooking ("Pastry") use, to the chick diet for 14 days produced a clear damage to the hepatic mitochondria, accompanied by an accumulation of glycogen and lipid droplets in the hepatocyte cytoplasm. These effects may be accounted for the high proportion of fat supplemented to the diets (20%). Pharmacy coconut oil induced a high percentage of cellular death when administered for 14 days. Fatty acid profiles in liver and hepatic mitochondria rapidly changed (24 hr) after both coconut oils supplementation to the diet. The accumulation of shorter chain fatty acids (12:0 and 14:0) was always higher after Pharmacy than after Pastry diet feeding. This fact may contribute, at least in part, to the cellular damage mentioned above especially after Pharmacy diet feeding. Mitochondrial ratios of saturated/unsaturated and saturated/polyunsaturated fatty acids rapidly changed in parallel to these ratios in both diets. Most of the mitochondrial parameters measured tend to recuperate the control values when diets were supplied for 5-14 days. Nevertheless, the maintenance of the mentioned ratios after 14-days Pharmacy diet feeding at significantly higher levels than those observed in control, seems to suggest the lack of the homeostatic mechanism in these membranes and could be also related with the high percentage of cellular death observed after this dietary manipulation.