Liver Total Fatty Acid Research Articles

Milk fat globule membrane plus milk fat increase docosahexaenoic acid availability in infant formulas

PurposeMilk fat globule membrane (MFGM) has components with emulsifier properties that could affect the provision of substrates to the brain. We evaluated the effects of MFGM plus milk fat addition to infant formulas on docosahexaenoic acid (DHA) availability and gut development.MethodsIn Experiment 1, suckling piglets were divided into 3 groups: Group L1 (n = 8): fed with a vegetal fat formula with palm oil; L2 (n = 8): canola oil formula and L3 (n = 8): milk fat + canola oil + 1% Lacprodan (3% MFGM of total protein content). In Experiment 2, Group L4 (n = 7): fed with canola oil + 1% Lacprodan (3% MFGM) and Group L5 (n = 5): milk fat + canola oil + 2% Lacprodan (6% MFGM). All formulas contained 0.2% DHA and 0.2% arachidonic acid.ResultsIn Experiment 1, DHA was similar among the groups in both total fatty acids and plasma phospholipids (PL). However, 3% MFGM (L3) increased significantly the proportion of DHA and LC-PUFA n-3 in liver total fatty acids, jejunum, and also in jejunum PL respect to the other formulas. There were no changes in gut histology, cell proliferation, apoptosis, or brain DHA content. In Experiment 2, higher MFGM dose was used. Then, higher DHA was not only found in peripheral tissues of 6% MFGM (L5) piglets but also in plasma PL, while a similar trend was observed in cortex PL (p = 0.123).ConclusionIn conclusion, MFGM plus milk fat may increase DHA availability of infant formulas which could contribute to their beneficial health effects.

Plasma triacylglycerol-reducing activity of ergosterol linolenate is associated with inhibition of intestinal lipid absorption

Abstract This study investigated the role of ergosterol linolenate in the alleviation of hyperlipidemia induced by a high-fat diet and further explored the expression of key genes involved in lipid absorption and metabolism in mice. Twenty-four male C57BL/6J mice were divided into three groups and fed one of three experimental diets: a high-fat diet (HF), or a HF diet with either ergosterol (ER) or ergosterol linolenate (EL), respectively, for 6 weeks. The results demonstrate that EL significantly reduced plasma triacylglycerol (TG) levels by 20%, weight gain by 50% and relative perirenal and epididymal fat by 23.6%. This was accompanied by a significant decrease in liver cholesterol, liver total fatty acids and fecal bile acids, accompanied by a marked increase in fecal total fatty acids. Ergosterol linolenate effectively counteracted steatosis induced by a high-fat diet. Ergosterol linolenate also altered the mRNA expression of key intestinal and hepatic genes involved in lipid absorption and metabolism. Of them, ergosterol linolenate significantly reduced the mRNA expression of intestinal microsomal triglyceride transfer protein (MTP), a key component in the formation of chylomicrons. Therefore, the plasma TG-reducing action of ergosterol linolenate can be largely attributed to reduced lipid absorption and increased fecal lipid excretion.

Lower Efficacy in the Utilization of Dietary ALA as Compared to Preformed EPA + DHA on Long Chain n‐3 PUFA Levels in Rats

We made a comparative analysis of the uptake, tissue deposition and conversion of dietary alpha-linolenic acid (ALA) to its long chain metabolites eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with preformed EPA + DHA. Diets containing linseed oil [with ALA at approximately 2.5 (4 g/kg diet), 5 (8 g/kg diet), 10 (16 g/kg diet), 25% (40 g/kg diet)] or fish oil [with EPA + DHA at approximately 1 (1.65 g/kg diet), 2.5 (4.12 g/kg diet), 5% (8.25 g/kg diet)] or groundnut oil without n-3 polyunsaturated fatty acids (n-3 PUFA) were fed to rats for 60 days. ALA and EPA + DHA in serum, liver, heart and brain increased with increments in the dietary ALA level. When preformed EPA + DHA were fed, the tissue EPA + DHA increased significantly compared to those given ALA. Normalized values from dietary n-3 PUFA to tissue EPA + DHA indicated that 100 mg of dietary ALA lead to accumulation of EPA + DHA at 2.04, 0.70, 1.91 and 1.64% of total fatty acids respectively in liver, heart, brain and serum. Similarly 100 mg of preformed dietary EPA + DHA resulted in 25.4, 23.8, 15.9 and 14.9% of total fatty acids in liver, heart, brain and serum respectively. To maintain a given level of EPA + DHA, the dietary ALA required is 12.5, 33.5, 8.3 and 9.1 times higher than the dietary EPA + DHA for liver, heart, brain and serum respectively. Hence the efficacy of precursor ALA is lower compared to preformed EPA + DHA in elevating serum and tissue long chain n-3 PUFA levels.

Geographical and seasonal differences in lipid composition and relative weight of by-products from gadiform species

The amount of available lipids and the lipid composition from gadiform species caught during three seasons in the Barents Sea, the Icelandic Sea and off the south coast of Ireland were determined. The size of the liver, constituting 1.3–6.9% of round weight, was affected by fishing ground. The fishing ground affected the lipid content in liver (30–78%) and viscera (2.2–7.1%). No significant effect of season was found on the lipid content of cod liver, while seasonal differences were found for other species and fractions. Polyunsaturated fatty acids (PUFAs) made up 21–45% and 34–63% of the total fatty acids in liver and viscera. Overall, effect of fishing ground and season were found on groups of fatty acid, and lower levels of PUFA were found in the liver of Icelandic cod. Depending on species and fishing ground, 550–1700 kg lipids can be obtained from the by-products from an average daily production of fillets (10 000 kg). The amount of available lipids was higher from gadiform species from the Barents Sea compared to the two other fishing grounds. All lipids extracted contained significant amounts of health-beneficial PUFAs.

Changes in the fatty acid profiles of hybrid red tilapia, Oreochromis mossambicus X O. niloticus, subjected to short-term starvation, and a comparison with changes in seawater raised fish

Juvenile hybrid red tilapia of mean weight 52.9 ± 2.80 g were starved for 45 days, and the liver and muscle fatty acid profiles of fed and starved fish determined on Days 0, 24 and 45. A corresponding group of fish were seawater adapted and were sampled on Day 45. In fed fish the total fatty acids in the livers (expressed in μg mg −1 lipid) decreased with growth (45 days), from 816 ± 16 to 600 ± 7 and 821 ± 25 to 589 ± 23 in females and males, respectively. This decrease was significant by the 24th day. In muscle, however, the amount of fatty acids in total lipid increased with growth, in females from 365 ± 21 to 489 ± 6 and in males from 387 ± 17 to 480 ± 17 μg mg −1 lipid. Compared with fed fish, during starvation the proportion of fatty acids in total lipid increased in both types of tissues but was still lower than at the initial level, significantly so in the liver. Twenty individual fatty acids were quantified as percent of total fatty acids in liver and muscle tissues of fish from different treatments during this study. In starved fish, liver monoenes decreased significantly ( P < 0.05), from 33.0 to 16.3% and 35.6 to 9.5%, and the percentage of polyunsaturated fatty acids (PUFA) increased significantly from 18.3 to 39.9% and 16.9 to 46.2% in females and males, respectively. Comparable trends were also observed in muscle, but in muscle the percentage of PUFA tended to be higher than in the liver. The fatty acids that occurred in the highest proportion were oleic acid (18:1 n − 9), followed by palmitic acid (16:0) and docosahexaenoic acid (DHA; 22:6 n − 3), collectively accounting for more than 50% of the total. The relative amount of PUFA, in particular DHA, increased considerably and very significantly with starvation. Principal component analysis of the fatty acid data effectively summarized the major differences among the experimental treatments, which included substantial differences in the fatty acid profiles between sexes, fed and starved animals and between fish raised in fresh- and seawater.

Effect of Δ 22-5β-taurocholenic acid and dietary fat on hepatic cholesterol and fatty acid in hyperglycemic-obese mice

Previous work demonstrated that hyperglycemic obese mice ( obob) fed a 1% corn oil diet accumulated cholesterol and fat in the liver when compared with nonobese littermates. The present experiment was carried out to test the hypothesis that feeding the bile acid analog Δ 22-5β-taurocholenic acid would correct this metabolic defect. Liver total fatty acid was greatly elevated in obob mice fed 1% corn oil compared with nonobese controls (21.04 ± 1.23% versus 4.41 ± 0.27%). Incorporation of [U- 14C]glucose into liver fatty acid was inhibited by taurocholenic acid in both obese and nonobese mice fed 1% corn oil. Taurocholenic acid reduced liver fatty acid in obob mice fed 1% corn oil to the level seen in nonobese mice (3.07 ± 0.22% versus 4.41 ± 0.27%). Cholesterol greatly accumulated in the livers of obob mice fed 1% corn oil compared with nonobese mice (0.97 ± 0.08% versus 0.28 ± 0.02%) and was reduced to normal by feeding taurocholenic acid (0.27 ± 0.05% versus 0.28 ± 0.01%) despite greatly elevating rates of incorporation of [U- 14C]glucose into liver cholesterol. Taurocholenic acid significantly reduced liver fat in obese mice fed 40% lard (11.62 ± 1.41% versus 5.87 ± 1.03%) but had no significant effect on the percentage of liver cholesterol (0.68 ± 0.05% versus 0.56 ± 0.04%). It is suggested that the elevation of liver cholesterol in obob mice fed 1% corn oil comes about through a defect in cholesterol removal from the liver, a defect corrected by taurocholenic acid via increasing the excretion of cholesterol and bile acids in the bile by an as yet unknown mechanism. The cholesterol accumulating in obob mice fed 40% lard occurs by a different mechanism than when these mice are fed 1% corn oil since it is unaffected by taurocholenic acid.

Metabolism of fatty acids in fish. II. Biosynthesis of fatty acids in relation to diet in the carp, Cyprinus carpio Linnaeus 1758

Carp, weighing 15–25 g, were maintained in the laboratory on a control diet, or on diets prepared from wheat or corn, and the incorporation of sodium (1− 14C)-acetate into their liver total fatty acids as well as into liver triglycerides and phospholipids was followed. The control diet was characterized by a high concentration of total lipids and linolenic acid, and the other two feeds by a low concentration of total lipids including linolenic acid and high concentration of carbohydrates. The highest rate of fatty acid biosynthesis was observed in fish given the corn diet, and the lowest rate was found in the carp on the control diet. Levels of radioactivity became very high in triglycerides of corn-fed fish. The major products of fatty acid biosynthesis were palmitic and oleic acids, in the corn-fed fish, while in the control fish almost 50% of the total radioactivity was in the long chain polyunsaturated fatty acids. The degree of labeling of oleic and palmitic acids appeared to depend on the level of linolenic acid in the diet. The results suggest that about 1% of linolenic acid in the diet is required to keep lipogenesis at a low level as well as to prevent hyperproduction of oleic acid. Linoleic acid seems to play a subordinate role in regulating lipogenesis in carp liver.

Seasonal acclimatization to temperature in cardueline finches

1. Seasonal variation in body constituents and utilization of lipid, protein, and carbohydrate during cold stress in American goldfinches were studied to determine relations of these functions to the pronounced seasonal shift in thermogenic capacity documented in a previous study (Dawson and Carey, 1976). 2. Mean body mass for adults increases from a low of 11.4 g in July to a high of 15.1 g in December and January. Seasonal variation in lipid content accounts for the major part of the observed changes in body mass, but such variation in water and protein content is also appreciable. 3. Linoleic acid (18∶2) is the predominant fatty acid in neutral lipids of liver, pectoralis muscle, and furcular depots at all seasons. Unsaturated fatty acids comprise a much greater proportion of total fatty acids in liver and pectoralis muscle during winter (71% and 73%, respectively) than in spring or fall. 4. Fasting winter goldfinches exposed to −10°C for 17 h overnight utilize significant amounts of body lipid. However, total body protein, liver and pectoralis muscle carbohydrate, and pectoralis muscle fatty acids do not differ significantly between control and cold-stressed individuals. 5. Glycogen stores in the pectoralis muscles are significantly higher in winter than in summer birds. Winter goldfinches exposed to −70°C utilize significant amounts of total body lipids and pectoralis glycogen. Birds tested in this manner in summer do not do so and quickly become hypothermic. 6. Histochemical characteristics and succinate oxidase activities of pectoralis muscles do not vary appreciably over the year. 7. Increased stores of body lipid and muscle carbohydrate and the ability to mobilize these substrates rapidly during cold stress seem to be key factors in the superior thermogenic capacities of winter goldfinches.

多糖類とコレステロール代謝 ６ 各種多糖類がラットの血清および肝臓コレステロール値に及ぼす影響

In this study, the effects of three kinds of mucilaginous polysaccharides on cholesterol metabolism and growth in rats were investigated.Fifty female rats were divided into 5 groups (10 rats/group) and fed on the following diets for 5 weeks: the cholesterol free basal diet (ST group), the hypercholesterolemic basal diet (CH group) supplemented with 1% cholesterol and 0.25% Na-cholate, and three polysaccharide diets containing 5% citrus pectin (PE group), Na-alginate (AL group) and Konnyaku powder (MA group) instead of a part of the sucrose in the hypercholesterolomic basal diet.Though serum cholesterol level of the CH group was remarkably elevated from 87mg% (ST group) to 133mg%, the supplement of pectin or Konnyaku powder significantly reduced this increment to the level of the ST group. The cholesterol lowering effect of Na-alginate was also recognized (P<0.05), but not so strong.Cholesterol, total lipids and total fatty acids in liver were also decreased by the addition of any polysaccharide. In this case, there was little difference among the polysaccharide groups.Slight retardation of growth and organs was found in the AL group, but there was no significant effect on both MA and PE groups.